ALBERT

Notes: The changes in porosity and elastic moduli of YSZ-containing nickel-based anode materials for solid oxide fuel cells were studied as a function of the fraction of reduced NiO. Anode samples were reduced in a gas mixture of 4% hydrogen and 96% argon for different periods of time at 800°C and their Young's and shear moduli were determined afterward at room temperature using resonant ultrasound spectroscopy and impulse excitation. It was found that the magnitude of Young's and shear moduli decreased significantly with increasing fraction of reduced NiO and that the magnitude of the elastic moduli of a fully reduced Ni–YSZ anode was ∼45% lower than that of unreduced NiO–YSZ. Because the elastic moduli of NiO are close to those of Ni, the observed decrease in the magnitude of the elastic moduli was found to be caused mainly by the significant increase in the porosity of the sample as a result of NiO reduction. Expressions are presented for the amount of porosity and the magnitude of the elastic moduli as a function of the fraction of reduced NiO.

Notes: Two- and three-dimensional SiCr/SiC composites have been prepared starting from Tyranno SA(tm) fiber preforms. Preform densification has been performed by a modified preceramic polymer impregnation and pyrolysis (PIP) process consisting of filling the preform large interbundle voids with SiC powder before the PIP process. This step was accomplished by low-pressure infiltration of a SiC powder dilute slurry through the preform thickness. Specimens were further processed with polymer impregnation and pyrolysis to determine the effects on structural, thermal, and mechanical properties of the obtained composites. High-temperature pyrolysis treatment, which promoted polymer derived SiC matrix crystallization, markedly increased thermal diffusivity.

Notes: Carbon is commonly added to sulfate-fined silicate-glass batches to enhance the fining process. Reactions between carbon and Na2SO4 modify the SOx emissions from Na2SO4 decomposition. Fourier-transform infrared (FTIR) spectrometry is used to analyze the emission of air pollutants from the isothermal decomposition of Na2SO4 + C undertaken using thermogravimetric analysis (TGA). The FTIR spectrometer is calibrated using standard gas mixtures containing CO, CO2, SO2, NO, and NO2. The collected spectra are quantified using the classical least-squares (CLS) approximation. The TGA-FTIR system provides SOx, and COx, concentrations versus time data from the isothermal decomposition of Na2SO4, in the presence of a carbon black. Mass spectrometry (MS) complements FTIR by being able to detect SO(g).

Notes: Different ratios of the precursor phases of SrFeO3–x (SFO) and SrMoO4 (SMO) were used to prepare Sr2FeMoO6 (SFMO) by a solid-state reaction. X-ray diffraction was used to identify the phases. A residual SMO was observed to exist in the sample with an SFO/SMO ratio of 0.9:1. The sample with a residual SMO phase had higher resistivity, lower magnetization, but higher low-field magnetoresistance (LFMR). High-resolution transmission electron microscopy was used to identify the compositions and phases. Nanometer-sized amorphous-like clusters of SMO phase were located inside the grains rather than at grain boundaries; however, some boundaries were rich in the strontium ion. The possible mechanisms for the conduction and the increase of LFMR of SFMO are discussed.

Notes: Submicro- and nano-sized liquid-phase-sintered SiC ceramics were mechanically tested by nanoindentation in the peak load range 5–400 mN. The submicro-sized sample showed a marked indentation size effect which the nano-sized samples did not exhibit. The relevance of indentation depth with respect to the microstructural scale has been outlined. In the investigated grain-size range, the hardness dependence on the grain size could be described by a load-dependent inverse Hall–Petch relation. Young's modulus was less microstructure- and load-dependent. Because of the very fine microstructure, the nano-sized SiC materials gave lower elastic values than the submicro-sized SiC ceramic.

Notes: Samples of composition Ba1−xLaxTi1−x/4O3, x= 0, 0.003, 0.03, and 0.10, were prepared by an alkoxide sol–gel route with final firing of ceramics at 1100°C, 2 h in air. All samples showed bulk insulating behavior with no evidence of semiconductivity caused by either direct donor doping or oxygen loss.

Notes: We have studied the rheological property evolution and hydration behavior of white and ordinary portland cement (type I) pastes and concentrated cement–polyelectrolyte suspensions. Cement composition had a marked effect on the elastic property evolution (G′(t)) and hydration behavior of these suspensions in the presence of poly(acrylic acid)/poly(ethylene oxide) copolymer (PAA/PEO), even though their affinity to adsorb such species was nearly identical. Both white and ordinary portland cement pastes exhibited G′0 values of ∼104 Pa and fully reversible G′(t) behavior until the onset of the acceleratory period (t= 2 h), where the pastes stiffened irreversibly. In contrast, cement–PAA/PEO suspensions exhibited G′0 values of ∼1 Pa and G′(t) behavior comprised of both reversible and irreversible features. Interestingly, ordinary portland cement–PAA/PEO suspensions experienced a gel-to-fluid transition on high shear mixing at short hydration times (〈1 h), and the particle network did not rebuild until ∼24 h of hydration. In sharp contrast, white portland cement–PAA/PEO suspensions remained weakly gelled throughout the initial stage of hydration even after high shear mixing. At longer hydration times (〉1 h), both cement–PAA/PEO suspensions exhibited G′i(t) ∼ exp(t/τc) with τc values of 5.6 and 1.3 h for ordinary and white portland cement, respectively. Our observations suggest that hydration phenomena impact interparticle forces during early stage hydration and, ultimately, lead to initial setting through the formation of solid bridges at the contact points between particles within the gelled network.

Notes: A new ceramic freeze-casting technique capable of manufacturing near room temperature with a sublimable vehicle was accomplished. Fluid-concentrated slurries of Al2O3 powder in molten camphene (C10H16) were prepared at 55°C. These slurries were quickly solidified (frozen) at room temperature to yield rigid solid green bodies, followed by frozen camphene removal by sublimation (freeze-drying) with negligible shrinkage. Sintering without any special binder burnout process yielded sintered bodies with over 98% theoretical density. The proposed advantages include (1) elimination of extremely cold temperatures, (2) elimination of troublesome binder burnout process, and (3) fast manufacturing cycle due to quick solidification.

Notes: Dense composites in the Ti-B-N system have been produced by reactive hot pressing of titanium and BN powders. The effect of the addition of a small amount of nickel (1–3 wt%) on the reaction kinetics and densification of TiN–TiB2 (40 vol%) composite has been studied. Composites of ∼99% of theoretical density have been produced at 1600°C under 40 MPa for 30 min with 1% nickel. The hardness and fracture toughness of these composites are 24.5 ± 0.97 GPa and 6.53 ± 0.27 MPa·m1/2, respectively. The microstructural studies on samples produced at lower temperatures indicate the formation of a transient liquid phase, which enhances the kinetics of the reaction and densification of the composite.

Notes: This paper presents new findings on ultrasonic spray pyrolysis of zirconium hydroxyl acetate precursor drops whose sizes were precisely measured using laser light diffraction technique. Precursor concentration plays a predominant role in determination of product particle size. At 0.01 wt% precursor concentration, conventional spray pyrolysis at 750°C using precursor drops 5–8 μm in diameter, generated by an ultrasonic nebulizer at 2.66 MHz, yielded uniform spherical yttria-stabilized zirconia (YSZ) particles 73 nm in diameter measured by scanning electron microscopy. The YSZ particle diameters were much smaller than those predicted by the one-particle-per-drop mechanism. Under similar reaction conditions, the high-throughput ultrasound-modulated two-fluid (UMTF) spray pyrolysis of larger precursor drops (28-μm peak diameter) also yielded spherical dense particles; they were significantly smaller in size than those produced by the low-throughput conventional ultrasonic spray pyrolysis of smaller drops (6.8-μm peak diameter).

Notes: Thermoelectric elements consisting of the layered polycrystalline materials of Al-doped ZnO and NaCo2O4 were prepared using the pulse electric-current sintering (PECS) method at 900°C for 3 min. Direct contact between the polycrystalline Al-doped ZnO and the NaCo2O4 was obtained in a single-step process for the stacked powders. The electrical conductivities of the polycrystalline materials prepared by PECS were higher than those of materials prepared by conventional sintering, despite their porous structure. The thermoelectric voltage of the 1-mol%-Al-doped ZnO and NaCo2O4 polycrystalline element (measuring ∼6 mm × 3 mm × 15 mm) was 83 mV at dT= 500 K, when the junction of the elements was at 800°C.

Notes: Pb(Zr,Ti)O3–Pb(Mn1/3 Nb2/3)O3 (PZT–PMnN) system has been studied for high-power piezoelectric applications. This study investigates this system to find out the composition with high-power density piezoelectric characteristics and low tem-perature coefficient of resonance frequency (TCF). It was found that the composition 0.9PZT–0.1PMnN (Zr/Ti = 0.51/0.49) modified with 6 mol% Sr exhibits a TCF of −8 ppm/°C (−20 to +80°C). Further, the dielectric and piezoelectric properties of this composition are as follows: kp= 0.53; Qm= 800; d33= 274; ε33/ε0= 1290 and tan δ=1.1%, which shows the suitability of this composition for ultrasonic devices used under fluctuating thermal environment.

Notes: Beam bending is an excellent method for measuring low permeabilities (≤10−18 m2) in homogeneous materials, because it is fast, requires no high pressure, and provides a concurrent measurement of the modulus of the material. The method was previously analyzed and substantiated for cylindrical or square beams. Recently, the analysis was extended to include isotropic and transversely isotropic rectangular beams. In this paper, the analysis is applied to measurements performed on cement paste, and it is shown that the solution for isotropic rectangular beams accounts for changes in the hydrodynamic behavior caused by changing the aspect ratio of the sample. The permeability and elastic modulus results are verified through comparison to previous measurements on cylindrical beams.

Notes: The deformation behavior of boron- and carbon-doped β-silicon carbide (B,C-SiC) with an average grain size of 260 ± 18 nm containing 1 wt% boron was investigated by compression testing at elevated temperatures. Extensive grain growth during deformation was observed. The stress–strain curves were compensated for grain growth by assuming power-law type of dependence on grain size and strain rate. The stress exponent n was ∼1.3 and the grain size exponent p was ∼2.7 at temperatures ranging from 1593° to 1758°C. The apparent activation energy of deformation Qd was ∼760 kJ/mol, which was lower than the activation energy for lattice diffusion of silicon and carbon in SiC and higher than that for grain-boundary diffusion of carbon in SiC. These results suggest that the deformation mechanism of the fine-grained B,C-SiC is grain-boundary sliding accommodated by the grain-boundary diffusion.

Notes: Chromium-containing stainless steel (SS) is a prospective material for use as an interconnect in solid oxide fuel cells (SOFCs). However, during operations at high temperatures, the growth of oxide scales causes the performance of the interconnect and SOFC as a whole to deteriorate. The coating of SS 446 with a conducting perovskite is a potential method of slowing the growth of oxide scale and, therefore, improving overall SOFC performance. In the present research, the structural characterization of a pure LaCrO3 thin film on the SS 446 substrates has been performed as a model material that can be used as a barrier coating for the metallic interconnect. The deposition of an amorphous La-Cr-O thin film on SS 446 was performed using radio-frequency (rf) magnetron sputtering. The deposited amorphous film was annealed in air to form the desired perovskite phase. The film underwent an amorphous to LaCrO4 phase transition during annealing at 500°C with further transformation to LaCrO3 orthorhombic phase during annealing at 700°C. A self-organized dendritic structure was reported as a result of the perovskite-phase formation. Although formation of various oxides, such as Fe2O3 and Fe3O4, was observed during the annealing of uncoated SS 446 in air, the coating of SS 446 surface with LaCrO3 film prevented formation of various oxide phases at the interconnect surface. The structural characterization of the films and SS 446 surfaces was accomplished using scanning electron microscopy with energy-dispersive X-ray analysis, X-ray diffractometry, micro-Raman spectroscopy, and nanoindentation.

Notes: The density, surface tension, and viscosity of the melts from the PbO-B2O3-SiO2 system have been measured at temperatures in the range 1073–1473 K. The effect of composition on these properties was also investigated. The density of the melt was found to increase linearly with increasing PbO content. Molar volume was derived from the density data, and its deviation from the additivity of partial molar volumes was calculated. These deviations in molar volume from those obtained from additivity rules have been used along with the ratio of various coordination numbers of boron (as reported by Bray) to discuss the structure of the melts. The surface tension was found to decrease with decreasing SiO2/B2O3 ratio, and to increase in the range of the PbO content between 30 and 60 mol%, showing a maximum at ∼60 mol% PbO, and then decreased with further additions. This result suggested that the surface tension would be affected primarily by the B2O3 content in the range of the PbO content between 30–60 mol%, and mainly by the PbO content in the range of the PbO content 〉60 mol%, respectively. The viscosity of the melt was found to decrease linearly with increasing PbO content. The results obtained indicate that the increase in viscosity with B2O3 was half that of SiO2 (on a molar basis), and an empirical equation has been proposed for the viscosity as a function of mole fraction.

Notes: Core/shell structures have been prepared via a mechanofusion system by employing several kinds of spherical polymers as a core material and Al2O3 powder or a mixture of Al2O3 and SiO2 powders as a shell material. The effect of the kind of core polymers on the quality of the resulting hollow alumina microspheres has been discussed on the basis of the thermal decomposition behavior of spherical polymers used as a core material. A large fraction of hollow alumina microspheres reflecting the shape and the particle size distribution of the core polymer could be fabricated after sintering at 1600°3C for 3 h, when highly cross-linked poly(methyl methacrylate) (PMMA) microspheres with a gel fraction of 99.03% were used as a core polymer, and abrupt firing at temperatures higher than 500°3C was adopted to remove the PMMA microspheres. The addition of 5 mass% SiO2 to the Al2O3 shell layer was found to be useful for maintaining the spherical shell structure during the firing process and for fabricating a large fraction of hollow alumina microspheres after the sintering.

Notes: Well-defined and stoichiometric spherical particles of BaTiO3 of narrow size distribution were produced at 82° and 92°3C by precipitation from chloride solutions in a strong alkaline environment. The size of the particles can be tailored in the range from ≅103 to 70–80 nm by increasing the barium concentration from ≅0.07 to 0.7 mol/L. The particles are composed of tight aggregates resulting from the assembly of several nanocrystals. The size of the nanocrystals decreases from 200–300 to 30–40 nm by increasing reactant concentration. At low barium concentration (≤0.07 mol/L at 82°3C, ≤0.06 mol/L at 92°3C), formation of BaTiO3 is strongly slowed down and nonstoichiometric, Ti-rich powders are produced. Under these conditions, the particles have the tendency to develop a dendritic-like morphology.

Notes: Crystals of δ-Y2Si2O7 (space group P121/c1) were examined using high-temperature powder X-ray diffractometry to determine their unit-cell dimensions from 296 to 1473 K. The lattice deformation induced by thermal expansion was investigated using matrix algebra analysis to determine the directions and magnitudes of the principal distortions (Λi, i= 1,2, and 3). The directions of Λ1 and Λ3 were defined by the acute angle Λ1c, which linearly decreased from 5(2)° to —5.5(3)° with increased temperature from 504 to 1473 K. The Λ2-axis invariably coincided with the crystallographic b-axis. The magnitudes of Λ1 and Λ2 steadily increased to, respectively, 1.0061(1) and 1.0068(1) during heating to 1473 K, while Λ3 remained almost constant for the entire temperature range. The mean principal distortion, Λm (= (Λ1+Λ2+Λ3)/3), steadily increased to 1.0044(1) with increased temperature to 1473 K. The coefficient of mean linear thermal expansion (α) was derived from the mean principal strain (Λm - 1) as α= (Λm - 1)/ΔT. The temperature dependence was determined to be α= 2.03 times 103+ 1.36(T - 296) (10-9 K-1). Provided that the rule-of-mixtures holds for the Y2Si2O7/Y2SiO5 composites as protective coating on SiC substrates, the volume fractions of 0.72-0.77 (70–75 mass%) would be necessary for the Y2Si2O7 component to match the α-values of both materials.

Notes: Microcellular silicon oxycarbide open cell ceramic foams were fabricated from a silicone resin. Microcellular foams, with a cell size ranging from ∼1–80 μm, were fabricated using poly(methyl methacrylate) microbeads as sacrificial templates. The compression strength of the foams decreased with increasing cell size.

Notes: Electroconductive zirconia-toughened mullite (TiN/ZTM) intragranular nanocomposite was fabricated by hot-pressing a powder mixture of nano-sized TiN, ZrO2(2Y), and mullite gel. The material showed a good sinterability and could be highly densified at a low temperature of 1300°3C. Sintering temperature strongly influenced the microstructure and electrical resistivity of the material. The electrical resistivity increased monotonously from 20 Ω-cm to 1.5 times 106°3Cm, as the sintering temperature was increased from 1300° to 1500°3C. TEM results indicated that such a phenomenon could be ascribed to the changes in the microstructure of the material, which led to a decrease in the connectivity of the TiN network in the sample as the sintering temperature was increased.

Notes: Effects of fluids on material removal rate, chipping damage, and surface roughness in the simulated clinical-dental machining of a dental-type glass ceramic were investigated. Significant differences in removal rate were obtained among the fluids investigated, but only a 4 wt% boric acid solution gave a higher removal rate than conventionally used water. Chipping damage was substantially lower for the boric acid and an oil-emulsion coolant compared with other fluids tested. Surface roughness was independent of the fluids used. The results indicate that improvement can be achieved in both material removal rate and machining damage by the appropriate selection of coolant chemistry.

Notes: This paper reviews the structures and properties of 10 binary, ternary, and quaternary crystals within the equilibrium phase diagram of the SiO2–Y2O3–Si3N4 system. They are binary compounds SiO2, Y2O3, Si3N4; ternary compounds Si2N2O, Y2Si2O7, and YSi2O5; and quaternary crystals Y2Si3N4O3 (M-melilite), Y4Si2O7N2, (N-YAM), YSiO2N (wallastonite), and Y10(SiO4)6N2 (N-apatite, N-APT). Although the binary compounds are well-known and extensively studied, the ternary and the quaternary crystals are not. Most of the ternary and the quaternary crystals simply have been referenced as secondary phases in the processing of nitrogen ceramics. Their crystal structures are complex and not precisely determined. In the quaternary crystals, there exists O/N disorder in that the exact atomic positions of the anions cannot be uniquely determined. It is envisioned that a variety of cation–anion bonding configurations exist in these complex crystals. The electronic structure and bonding in these crystals are, therefore, of great interest and are indispensable for a fundamental understanding of structural ceramics. We have used ab initio methods to study the structure and bonding properties of these 10 crystals. For crystals with unknown or incomplete structural information, we use an accurate total energy relaxation scheme to obtain the most likely atomic positions. Based on the theoretically modeled structures, the electronic structure and bonding in these crystals are investigated and related to various local cation–anion bonding configurations. These results are presented in the form of atom-resolved partial density of states, Mulliken effective charges, and bond order values. It is shown that Y–O and Y–N bonding are not negligible and should be a part of the discussion of the overall bonding schemes in these crystals. Spectroscopic properties in the form of complex, frequency-dependent dielectric functions, X-ray absorption near-edge structure (XANES), and the electron energy-loss near-edge structure (ELNES) spectra in these crystals also are calculated and compared. These results are discussed in the context of specific bonding configurations between cations (silicon and yttrium) and anions (oxygen and nitrogen) and their implications on intergranular thin films in polycrystalline Si3N4 containing rare-earth elements.

Notes: Simultaneous synthesis and sintering of hexagonal α-Ti1−x-Alx(N) (0 ≤x≤ 0.08) solid solutions, which contain a small amount of nitrogen, have been performed by a self-propagating high-temperature combustion method under a nitrogen pressure of 4 MPa. Dense materials (∼99% of theoretical) prepared directly from a mixture of elemental (Ti and Al) powders reveal homogeneous microstructure composed of fine grains (12–16 μm). α-Ti1−xAlx(N) (x= 0.02; Ti0.98Al0.02N0.26) exhibits a three-point bending strength σb of 390 MPa, a Vickers hardness Hv of 9.24 GPa, and a fracture toughness KIC of 4.89 MPa·m1/2; their mechanical properties are much improved by doping Al into α-Ti(N), in comparison with those (σb= 245 MPa, Hv= 9.02 GPa, and KIC= 3.77 MPa·m1/2) of α-Ti(N) fabricated under the same conditions.

Notes: Electrophoretic deposition has been used to synthesize nickel–alumina, functionally graded materials from NiO and alumina suspensions in ethanol. Suspension stability and the kinetics of deposition were studied to determine optimum conditions. Deposition starts with an alumina suspension into which a stream of NiO suspension is injected at various flow rates to obtain the desired profiles. The latter were controlled by varying the deposition current density and component flow rate. The green bodies obtained were sintered in Ar/H2 atmosphere to reduce the NiO to nickel. Various gradation profiles were obtained illustrating the facility of EPD to synthesize continuously graded materials. NiO was used as the precursor for nickel to alleviate settling and rough columnar deposit problems.

Notes: X-ray diffraction (XRD) patterns from nominally β-SiC specimens often differ from those expected for the cubic crystal structure. These differences include the presence of additional peaks, enhanced background intensities, peak broadening, changes in relative peak heights, and shifts in peak positions. It has long been recognized that they are due to the presence of stacking faults, and models relating the experimental observations to stacking fault population have continued to evolve. The presence and relative magnitude of these features vary among different β-SiC specimens. In this work, computer simulations were used to show that the variations are closely related to differences in the type and spatial distribution of stacking faults in each specimen. In these simulations, stacking sequences were generated using a selectively activated 1-D Ising model with a Boltzmann-type probability function for specifying errors, which allows a wide variety of fault configurations to be generated. Direct correlations between different features in the XRD data to the underlying fault population are demonstrated, which are discussed in this paper. It is also shown that this computer model is general, in the sense that many of the models presented in prior work can be interpreted as limiting cases of it.

Notes: Live cells of E. coli O157:H7 were labeled by 4′,6-diamidino-2-phenylindole (DAPI) in buffers of different pH. The extent of labeling was relatively insensitive to pH in the range of 6.5 to 9.5. The fluorescence intensity of ± 104 DAPI-labeled bacteria per mL in optical cuvettes could be detected by a luminescence spectrometer. With a fluorescence microplate reader attachment, less than 103 of labeled bacteria could be measured. DAPI-labeling inhibited the growth and respiratory activities of the bacteria. The addition of 0.5 to 6 mM concentrations of ATP induced a substantial increase in the fluorescence of labeled bacteria. Maximal enhancement by ATP was observed from bacteria still maintaining low levels of physiological activities. The enhancement favored more alkaline media with pH greater than 9. A replacement of ATP with ADP or AMP diminished the extent of enhancement. Other triphosphate nucleotides did not enhance fluorescence of DAPI-labeled bacteria. Comparable ATP enhancements were also observed with Pseudomonas alcaligenes and Shewanella putrefaciens. Solubilization/destruction of cell membranes of labeled bacteria by detergents essentially eliminated the ATP enhancement. Absorption and fluorescence spectroscopic measurements indicated that ATP could interact with free and bound DAPI. These results suggest that observed ATP enhancement in fluorescence intensity of DAPI labels in intact cells may be applied to increase the sensitivity of microorganism detection.

Notes: Fungal biota, with special reference to the genus Penicillium, was studied in 52 samples of commercial cheeses (10 fresh, 17 semiripened and 25 ripened) made from different types of milk (cow, ewe, goat and mixed) produced in southern Spain. In 41 of the total of cheeses analyzed (79%) molds were isolated. Penicillium was identified in 63% of the samples, Mucor spp. in 27%, Geotrichum candidum in 17% and Cladosporium herbarum in 10%; eleven other fungal genera were detected ranging from 2 to 4%. Thirty-five species of Penicillium were analyzed with the following distribution: 7 in fresh cheese, 16 in semiripened cheese and 30 in ripened cheese. The incidence of Penicillium spp. was also greater in the cheeses with a higher degree of ripeness, i.e. 20% in fresh cheese, 71% in the semiripened and 76% in the ripened cheese.

Notes: Challenge studies were carried out on raw, cooked, and sterilized surimi nuggets, inoculated with 104spores/g of C. botulinum type E spores. All products were packaged in air and air with an Ageless SS oxygen absorbent and stored at 4, 12 and 25C. Toxin was not detected in any raw product throughout storage (28 days). The absence of toxigenesis was attributed to the low pH (4.1–4.3) due mainly to the growth of lactic acid bacteria (107CFU/g). Toxin was also not detected in any cooked product after 28 days. Product pH did not decrease as previously (due to the absence of LAB), but counts of C. botulinum still decreased throughout storage. In sterile nuggets, C. botulinum counts increased to 106 cfu/g at both 12 and 25C, respectively, by 28 days. Lactic acid bacteria and Bacillus spp.were not detected throughout the 28 days storage period. Toxin was detected by days 28 and 14 at 12 and 25C, respectively, and toxigenesis preceded spoilage. The absence of toxin in cooked nuggets was attributed to the anti-botulinal role by Bacillus species, the predominant spoilage bacteria in cooked nuggets.

Notes: Packages containing chubs of summer sausage were inoculated with about 108 cfu/mL of a three-strain mixture of Listeria monocytogenes and vacuum sealed. The fate of the pathogen was then monitored after pasteurization at 150F (66C), 170F (77C), 190F (88C) and 21 OF (99C) for 0 to 240 s. Pathogen numbers were reduced by about 3 log10 cfu per gram within 30, 60, or 90s at 21 OF (99C), 190F (88C), or 170F (77C), respectively, whereas numbers were reduced by 〈2.0 log10 cfu per gram after 240 s of heating at 150F (66C). The calculated D values were 2.08 min at 150F (66C), 0.84 min at 170F (77C), 0.37 min at 190F (88C), and 0.28 min at 21 OF (99C). These results establish the feasibility of using pasteurization to control L. monocytogenes in packaged summer sausage.

Notes: Book review in this ArticleWORLD HEALTH STATISTICS QUARTERLY DALLAS G. HOOVER

Notes: Decimal reduction times (D-values) for Saccharomyces cerevisiae ascospores inoculated into pasteurized orang juice ranged from 4 to 76 s at pressures between 500 and 350 MPa. At the same pressures, D-values of S. cerevisiae vegetative cells ranged from 1 to 38 s while those for the native microflora in nonpasteurized Hamlin orange juice were between 3 and 74 s. Corresponding z-values were 123, 106 and 103 MPa for ascospores, vegetative cells and native microflora, respectively. Native microorganisms that survived high pressure treatments included yeasts, gram-positive and gram-negative bacilli. Pectinmethylesterase activity in nonpasteurized Hamlin orange juice was reduced to 5% of initial activity after 30 s at 900 MPa.

Notes: The objective of this study was to investigate awareness and attitude regarding food-related hygienic practices in the home. For this purpose and within a sanitary education program in pricary schools in a town of Central Italy, a questionnaire was used to collect information from parents of pupils. The questionnaire included questions in four major areas: personal hygiene and cleaning up procedures; meal preparation; food storage; and knowledge of key terms and concepts pertaining to food safety. Analysis of 183 questionnaires showed either risk of cross contamination, improper thawing of food, or inadequate storing and reheating of cooked foods during home food preparation and storage practice. Particularly, 73% of respondents thawed large pieces of frozen food at room temperature; 89% did not reheat cooked food after it had been stored; 75% stored raw meat and poultry in the upper shelves of refrigerators. Precise information on the lack of food safety practices will facilitate the development of proper consumer education programs.

Notes: Microbiological studies on a popular maize product (kwoka) with or without a soybean supplement (20 or 30%) were carried out during production and storage at 26–32C. Soybean -supplementedproduct had greater microbial diversity and higher populations than the unsupplemented control. The diversity was most evident at the slurry stage (blended mixture before steaming) which contained ten different microbial genera including Aspergillus, Enterobacter, Bacillus, Lactobacillus, Micrococcus and Pediococcus. A dramatic decrease occurred after steaming which killed most of the molds and Gram-negative bacteria. However, within 1 day of storage, a sharp increase was observed in the microbial population of all samples and maximum load occurred in 20% soybean supplemented “kwoka” at the end of storage. The microbiota became less diverse with storage and was dominated by Bacillus, Lactobacillus and Micrococcus. packaging of ‘kwoka’ in traditional leaves was microbiologically inferior to polyethylene packaging. Changes in the acidity of 30% supplemented ‘kwoka’ were less dramatic compared to the other products. The lactics were primarily responsible for the spoilage of the products (especially the 20% supplemented) after approximately 3 days of storage at tropical ambient temperature of26–32C.; Accepted for Publication August 8, 1997

Notes: Chicken, lamb and buffalo meat were subjected to low-dose gamma irradiation (2.5 kGy) and stored at 0–3C. Lipid peroxidation in terms of thiobarbituric acid (TBA) number and carbonyl content were monitored during storage. While irradiated meat showed slight increase in TBA number and carbonyl content on storage as compared to nonirradiated meat, this did not affect the sensory qualities of meat. Free fatty acid content decreased markedly on irradiation. Irradiated meats were microbiologically safe and sensorily acceptable up to 4 weeks in the nonfrozen state (0–3C) while nonirradiated meat had a shelf-life of less than 2 weeks.

Notes: In a nonhypothetical laboratory experiment, participants were willing to pay an average of $0.71 for the right to exchange a typical meat sandwich for a sandwich irradiated to eliminate the potential risk of foodborne bacteria. Forty-one of sixty participants (68.3%) were willing to pay some positive amount. Tobit analysis was used in order to allow for the fact that Willingness To Pay (WTP) was censored at zero. WTP was interpreted as the demand for irradiation to control foodborne disease. A positive WTP was interpreted as acceptance of irradiation. The aggregated WTP greatly exceeds the estimated direct costs of foodborne disease, and the estimated costs of irradiation for many food products. There was a positive relationship between WTP and the perceived risk of foodborne disease, and a negative relationship between WTP and years of education.

Notes: The potential of using trisodium phosphate (TSP) to reduce bacterial populations in fresh fishery products was explored since TSP has recently been approved by USDA for its usage in poultry processing to eliminate Salmonella contamination. Fresh headed shrimp and rainbow trout fillets were inoculated with L. monocytogenes before dipped in tap water, 10% TSP, or 20% TSP solutions and overwrap-packaged. Surface pH values, psychrotrophic plate counts, and L. monocytogenes counts of inoculated shrimp and trout fillets were determined after 0, 3, 6, and 9 days of storage at 4C. The TSP treatment resulted in relatively high residual surface pH values (11–12) initially in both shrimp and trout fillets. Compared to tap water dipping, TSP treatment did not significantly reduce psychrotrophic or Listeria populations in shrimp. However, the 20% TSP treatment significantly (p 〈 0.05) lowered 0-day psychrotrophic and L. monocytogenes counts of trout fillets and remained effective for 6 days during storage at 4C.

Notes: Enterohemorrhagic Escherichia coli O157:H7 (EHEC) is recognized as a frequent cause of gastroenteritis ranging from mild to severe bloody diarrhea. The Shiga-like toxin produced by EHEC can result in hemolytic uremic syndrome, now the major cause of acute kidney failure in children in the United States. Inadequately cooked beef is most commonly implicated in the transmission of EHEC, although only a small fraction of cattle appear to harbor the organism. In several studies EHEC positive herds were detected only in the summer months correlating with the occurrence of human infections. Numerous E. coli strains have been shown to enter a viable but nonculturable (VBNC) state as a result of environmental stresses, including low temperature. Using traditional plating methods and the BacLight Molecular Probe, we monitored EHEC strains incubated in river water (RW) and artificial sea water (ASW) at temperatures of 5C and 25C for their entry into the VBNC state. EHEC strains remained culturable for over 40 days in both ASW and RW incubated at 25C. In ASW, these levels were higher than a non-EHEC control. At 5C, the number of culturable EHEC cells dropped gradually in both RW and ASW. Using the BacLight Molecular Probe, we were able to demonstrate that these cells, though not culturable, were viable indicating entry into the VBNC state. Our study suggests that temperature and not salinity is the primary signal for entry into this state.

Notes: Inactivation of Escherichia coli O157:H7 by pulsed electric field, benzoic or sorbic acid, alone or in combination was investigated. When the cells of E. coli O157:H7 were suspended in 10% glycerol and treated with a single highvoltage (12.5 kv/cm) electric pulse at 25C, the count decreased by 1.1–1.6 log10 CFU/mL. Presence of benzoic and sorbic acid (1000 ppm) in the suspending medium, at pH 3.4 without electric treatment, decreased the count by 1.9–2.5 and 0.6–1.1 log, respectively. A synergistic killing effect between the high electric pulse and organic acid was observed at pH 3.4, but not at pH 6.4. When the cell suspension of E. coli O157:H7 was treated with five electric pulses in the presence of benzoic or sorbic acid at pH 3.4, the count decreased by 5.6 and 4.2 logs, respectively. Inactivation of the pathogen by combinations of electric pulse and organic acid was enhanced by an increase in temperature, field strength, and number of electric pulses, Inactivation was greater when the cells were suspended in ionic suspending media (0.1% NaCl or 5mM phosphate buffer) than in nonionic media (10% glycerol or 1% sucrose).

Notes: Ninety samples of maize, chick-peas and groundnut seeds collected from the Egyptian market were found to be heavily contaminated by molds. Alternaria, Aspergillus, Cladosporium, Eurotium, Fusarium, Mucor, Penicillium and Rhizopus were the most common fungal genera isolated from nondisinfected seeds. Aspergillus alutaceus, A. flavus, Fusarium verticillioides and F. oxysporum were isolated from all surface-disinfected seeds and were reported to produce ochratoxin A, aflatoxin B1 and zearalenone, respectively. Irradiation at a dose 4.0 kGy reduced the mold growth greatly relative to unirradiated controls. There was no growth at dose 5.0 kGy. On the basis of the radiation survival data, the decimal reduction values D10 for A. alutaceus, A. flavus and F. verticilliodies were 0.70. 2.10 and 0.93 kGy in maize. A dose of 5 kGy inhibited the toxigenic molds and mycotoxin formation in seeds. Aflatoxin B1 and ochratoxin A were detected in maize and chick-peas, whereas zearalenone was detected in maize samples. Application of radiation at a dose of 6.0 kGy detoxified aflatoxin B1 by 74.3–76.7%, ochratoxin A by 51.3–96.2% and zearalenone by about 78%.

Notes: Fresh-cut cantalcupe has been recalled due to the possible presence of Listeria monocytogenes. Several studies have reported that naturally occurring microflora of vegetable surfaces may be antagonistic to pathogen attachment, growth or survival. To test this possibility for L. monocytogenes and cantaloupes, whole melon were treated with water, ethanol (70%) or chlorine (200 ppm) to reduce the native microflora on the melon surfaces. Treated or untreated melons were immersed in a six strain cocktail of L. monocytogenes (107 CFU/mL) for 10 min and then allowed to dry for 1 h inside a biosafety cabinet followed by storage at 5, 10 and 20C for 15 days. Fresh-cut pieces prepared from the treated or untreated melons and directly inoculated with L. monocytogenes (3.48 log CFU/g) were stored under the same conditions listed above. Populations of L. monocytogenes and five classes of native microflora were investigated. Growth of L. monocytogenes in sterile or nonsterile rind and fresh-cut homogenates was also studied. The population of L. monocytogenes recovered from inoculated (103 to 108 CFU/mL) whole melons given no disinfection treatment or washed with water was significantly less (P 〈 0.05) than that recovered from melons treated with chlorine or EtOH. In general, populations of L. monocytogenes declined on the surface of treated and untreated whole melons and on fresh-cut pieces over the 15 days storage period at the temperatures tested. However, the decline in pathogen populations was less rapid in the presence of reduced populations of native microflora. Higher populations of L. monocytogenes were attained in sterile tissue homogenates than in nonsterile homogenates. Addition of yeast and mold to sterile rind homogenates was highly inhibitory to growth and survival of the pathogen. The results of this study indicate that native microflora of whole cantaloupe inhibited attachment to rind surfaces as well as survival and growth of L. monocytogenes on cantaloupe surfaces and homogenized fresh-cut pieces. Thus, L. monocytogenes recontamination of melons having a reduced level of native microflora following application of a disinfection treatment may be a food safety concern.

Notes: Streptococcus pyogenes is widely recognized as a human pathogen. Whereas person-to-person transmission is the most common transmission mechanism for this pathogen, some outbreaks of S. pyogenes disease have been reported to occur in association with consumption of contaminated foods such as shrimp or potato salads. In this study, the behavior of S. pyogenes was studied in mashed potatoes as a function of storage temperature, types and amount of background biota and type of ingredients. Combined mashed potatoes (potatoes, butter, milk, egg and table salt) or plain mashed potatoes (potatoes only) were inoculated with a 5-strain cocktail of S. pyogenes and stored at 7, 25, 35 or 37C. At intervals during storage, samples were collected for counting S. pyogenes in blood agar plates or blood agar added with sodium azide, polymyxin and crystal violet. Mashed potatoes obtained from fast-food restaurants were used to determine the fate of S. pyogenes as affected by changes in aerobic mesophiles, coliform and lactic acid bacteria counts. S. pyogenes was able to survive in mashed potatoes stored at 7C and to grow in mashed potatoes stored at 25 or 37C with lag phase lengths of 3 and 2 h and generation times of 26.0 and 25.3 min, respectively. The generation time of S. pyogenes in plain mashed potatoes was 30.7 min at 35 C. Presence of active background biota at 2–3 log10 CFU/g concentrations did not prevent growth of S. pyogenes when stored at 35C. These results contribute to a better understanding of the potential for S. pyogenes to cause foodborne outbreaks.

Notes: Survival of stationary phase Listeria innocua (as surrogate microorganism for L. monocytogenes) inoculated in apple juice (pH 3.3 or 3.8) supplemented with vanillin (1,500 ppm or 3,000 ppm) or potassium sorbate (500 ppm or 1,000 ppm) and stored at room temperature was studied. L. innocua survived in apple juice without the preservatives at pH 3.3 or 3.8, with minimal population reductions. In the juices with the incorporation of potassium sorbate or vanillin, L. innocua behavior depended on the pH value, the type of antimicrobial and its concentration. At pH 3.3, the presence of vanillin (3,000 ppm) or potassium sorbate (1,000 ppm or 500 ppm) decreased L. innocua counts, with population reductions ranging from 4 to 5 log cycles after a 4 h – 8 h exposure at 30C. However, at pH 3.8, L. innocua showed sensitivity only to 3,000 ppm vanillin. Survival curves were successfully fitted using a Weibull type distribution of resistances. The results suggest that the use of potassium sorbate or vanillin could prevent the survival of L. innocua in contaminated unpasteurized and pasteurized apple juice. Vanillin, a natural antimicrobial, would be particularly suitable as an antilisterial additive for less acidic apple juice.

Notes: To monitor the bacteriological quality of raw milk and raw milk farm products, 143 samples of raw farm milk and 100 samples of raw milk farm products, 64 butters, 9 yogurts, 16 cheeses, 7 ice creams and 4 fresh cheeses, produced in Belgium were examined for coliforms, β-glucuronidase positive Escherichia coli, verotoxin producing Escherichia coli O157, Staphylococcus aureus, Salmonella spp., Listeria spp. and Listeria monocytogenes. The results were compared with the threshold and maximum values of the EC directive 92/46/EC or the maximum values of the Belgian Order of Council from September 3, 2000. The presence of staphylococcal enterotoxins was investigated on samples with S. aureus counts higher than the legal threshold values mentioned in the EC directive or, if not regulated in the directive, higher than the maximum value mentioned in the Belgian Order of Council. The obtained results for the hygiene-indicators coliforms, β-glucuronidase positive E. coli and S. aureus in the raw milk samples were comparable with most other industrialized countries. Compared to a prevalence of 0.7% and 6.3% for, respectively, E. coli O157 and L. monocytogenes, no Salmonella was found in the 25 g raw milk farm samples. The isolated E. coli O157 strain was confirmed to be verotoxigenic; it was positive for VT2, eaeA and hlyA. In butter not only a prevalence of 18.7% for L. monocytogenes in 25 g was found but also the maximum values for the hygiene-indicators mentioned in the Belgian Order of Council were often exceeded. No significant difference was found between the count of hygiene-indicators and the presence of Listeria spp. as well in raw milk as in raw milk butter. The bacteriological quality of on-farm made raw milk butter suggest that suitable hygienic conditions are not always provided. One of the 7 ice cream samples contained L. monocytogenes in 25 g.

Notes: Factors that significantly affect BAX® PCR detection of Listeria monocytogenes from optimized Penn State University (oPSU) broth were identified and optimized. Concentration of PCR product was significantly reduced by BAX™ protease and significantly increased by eliminating the lysis step and directly diluting oPSU broth prior to PCR. A simple oPSU broth-BAX® PCR-PicoGreen® (PSU-BAX-PicoGreen) system was developed and compared with current methods for detecting low levels of L. monocytogenes in commercial milk and hot dogs. All 30 milk samples inoculated with 10–20 CFU per mL L. monocytogenes were positive by FDA, BAX® and PSU-BAX-PicoGreen methods and all 42 uninoculated milk samples were negative by all of the above methods. All 30 hot dog samples inoculated with 10-20 CFU/g L. monocytogenes were positive by the USDA and PSU-BAX-PicoGreen methods, however, 2 hot dog samples gave indeterminate results with the standard BAX® method. All 42 uninoculated hot dog samples were negative by USDA, 9 were indeterminate by BAX® and 2 were positive by PSU-BAX-PicoGreen. The PSU-BAX-PicoGreen system may provide a simple and accurate method for rapidly screening pasteurized foods for both injured and noninjured L. monocytogenes.

Notes: In this study, 851 Staphylococci isolates isolated from 38 raw milk samples were investigated for DNase activity and slime production. The 851 Staphylococci isolates were identified as 704 Staphylococcus aureus and 147 coagulase-negative staphylococci. Coagulase – negative staphylococci isolates were classified as 32.7% S. cohnii, 19.7% S. hominis, 19.1% S. xylosus, 12.9% S. epidermidis, 8.2% S. capitis, 4.8% S. haemolyticus, 1.4% S. simulans and 1.4% S. saprophyticus by using Dichotomous scheme. DNase agar was used to investigate for DNase activity. DNase activity was found in 93.6% of 704 S. aureus and 10.2% of 147 coagulase – negative staphylococci. DNase activity was positive in 42.9% of S. haemolyticus, 20.7% of S. hominis, 17.9% of S. xylosus and 2.1% of S. cohnii isolates. No DNase activity was found in S. epidermidis, S. capitis, S. simulans and S. saprophyticus isolates. Slime production of S. aureus and coagulase – negative staphylococci from raw milk samples was investigated by using Congo Red Agar method. Slime production was positive in 5.1% of S. aureus and 42.2% of 147 coagulase – negative staphylococci. Slime production was positive in 100% of S. simulans, 68.4% of S. epidermidis, 50% of S. cohnii, 50% of S. saprophyticus, 37.9% of S. hominis, 32.1% of S. xylosus and 16.7% of S. capitis isolates. None of the 7 S. haemolyticus isolates had slime production. In conclusion, slime production and DNase activity are important virulence factors to identify pathogenic staphylococci.

Notes: Calabaza (Curcubita moschata) is a tropical squash which is gaining popularity as a specialty crop for agricultural producers in the Northeast United States. It is commonly marketed by being cut in half, wrapped in plastic and may be held unrefrigerated until sold. This method of display is essential for consumer acceptance, yet unrefrigerated storage means that some potential for food safety problems exists. Experiments were conducted to determine the potential for bacterial growth during storage of cut calabaza. Freshly cut calabaza contained between 1.3 and 4.7 log10CFU/g aerobic mesophiles. By 10 h, duplicate counts from some samples exceeded 4 log10 CFU/g. After 24 h of room temperature storage, total aerobic plate counts ranged from 5.2 to 7.7 log10 CFU/g. Rapid bacterial growth on cut calabaza stored at room temperature indicates that these products are highly perishable, and may be able to support the growth of pathogenic bacteria, should they be introduced during the slicing process.

Notes: The aim of this study was to investigate fecal shedding and transmission of E. coli O157 in cohorts of cattle within a feedlot, to assess subsequent contamination of carcasses with this pathogen and to identify risk factors associated with fecal shedding of E. coli O157. A cohort of 133 heifers housed infour adjacent pens was examined over a five month period, from entering the feedlot to slaughter. Individual rectal fecal samples and pen environmental samples were taken at monthly intervals. The entire outer and inner surfaces of a carcass side of each animal were swabbed immediately following slaughter.E. coli O157 was isolated from 136 (23%) of the 600 rectal fecal samples; 96% of which contained virulent markers. One hundred and sixty environmental samples were examined and E. coli O157 was isolated from 46 (29%), all of which contained virulent markers. E. coli O157 was not isolated from any of the dressed carcasses. The prevalence of E. coli O157 fecal shedding may be related to the pen and E. coli O157 contamination of the pen floor feces, water trough and feed.E. coli O157 should be considered as a pathogen shed in the feces of a substantial proportion of feedlot cattle. However, with good hygienic practice at harvest, a very low level of this pathogen can be achieved on dressed carcasses.

Notes: Polymeric films were coated with nisin, an antimicrobial peptide, for potential application in shelf-life extension of food. Five commercial packaging films with varying surface energies were compared. The highest antimicrobial activity was observed on the most hydrophobic nisin-coated films (surface energy ± 32 dyne/cm). The binding affinity of nisin to the surface of ethylene acrylic acid copolymer (surface energy = 32 dyne/cm) was investigated. Films were coated in nisin solutions under varying conditions including nisin concentration, contact time, solution's volume to film area ratio, pH of coating solution and temperature during coating. Stronger nisin activity was detected on films as the coating time increased from 30 s to 2 h. Higher nisin coating concentration also promoted the binding of nisin to films with saturation level observed at 250 μg/mL. Films coated with nisin using a higher solution to film area ratio (0.84 compared to 0.14 and 0.28 mL/cm2) also exhibited higher nisin activity.

Notes: Biofilms enable foodborne pathogens to resist removal from surfaces, survive disinfection and elude detection. This study evaluated the use of Calcofluor, which binds to polysaccharides containing β-D-glucans, to detect biofilms produced by Salmonella enterica serovar Berta and Salmonella enterica serovar Typhimurium DT104 (St DT104), Escherichia coli, Aeromonas hydrophila, Vibrio cholerae O139 and Hyphomonas adhaerens. Biofilms produced by St DT104, S. berta and V. cholerae on five types of surfaces (glass, polypropylene, Teflon™, stainless steel and aluminum) were detected by Calcofluor. Results suggest the potential use of Calcofluor as probes of foodborne pathogens in biofilms.

Notes: A study to determine the incidence of Staphylococccus aureus in 705 meals from several cafeterias in Valencia, Spain was undertaken. Out of the 705 studied meals, 81 samples (11.1%) had coagulase positive staphylococci with a range of S. aureus from 100 to 53000 cfu/g. The four highest values (〉 10,000 S. aureus cfu/g) were obtained with Russian type salad, meatballs, chicken croquettes and salad. These products involved more handling stages. These data show that food handlers may contribute to food poisoning and that there are some handling practices that require more attention.

Notes: A survey of Irish consumers examined their concerns for the safety of food, their level of knowledge of safe food practices and their awareness of institutional structures to ensure the safety of Irish beef. Sixty-four percent of the sample expressed concern for the safety of food. Concerns cited include freshness of food, BSE/CJD, antibiotic residue, hygiene standards and bacteria. They perceive many causes of food poisoning and their level of awareness of pathogens varies, depending on the pathogen. The level of knowledge of safe food practice in cooking was good. However, it was lower for food storage practices. Males and those with lower levels of education were less likely to be aware of adequate food safety procedures and need to be the focus of educational programs on safe food handling. As less than half the sample (49%) was aware of institutional structures and 32% of schemes that ensure the safety of Irish beef, it is concluded that it is imperative to more clearly communicate to the public the assurances of any scheme set up. There is also a need to increase awareness level of the bacteria Campylobacter.

Notes: Starking apples, classified by the decay proportion on the fruit surface as sound, 30, 60 or 100% decayed were used in the production of apple juice. Then patulin, fumaric acid, HMF, pH, brix and Hunter L, a and b values of apple juice samples were determined. Patulin and fumaric acid analysis were done with HPLC. The patulin concentration in juice samples produced with Starking apples that are sound, 30, 60 and 100% decayed ranged between 0.0–15.9 μg/kg, 47.1–500.3 μg/kg, 156.4–2257.5 μg/kg, 54.9–2508.6 μg/kg, respectively. The fumaric acid concentration in the same juice samples ranged between 0.00–0.20 mg/kg, 0.23–0.69 mg/kg, 0.41–2.08 mg/kg and 1.40–4.14 mg/kg. In general, the color values (L, a, b) of the samples produced from 100% decayed apples measured by reflectance with a Hunter colorimeter were low when compared with the others.

Notes: As a contribution to Good Manufacturing Practice (GMP) programs, we have analyzed products produced and offered by ready-to-eat food stores. Two hundred and seventy four samples of a wide variety of foods from 19 different shops were analyzed. Aerobic counts, total coliforms and yeast and molds were enumerated in each sample. Food stores were evaluated using a GMP check-list. They were grouped in three classes: Class III, nonsatisfactory GMP; Class II, partially satisfactory GMP; and Class I, satisfactory GMP. From the results of microorganism counts in the Class I food shops the following maximum counts are proposed for cooked ready-to-eat foods: aerobic colony count: 105 cfu g−1. It is coincident with satisfactory microbiological quality of many category 3 foods drawn up by Public Health Laboratory Service (PHLS).

Notes: Microbiological, physicochemical and sensory quality changes in togwa during storage at ambient tropical temperatures were monitored in unpasteurized and pasteurized samples with added sodium benzoate, potassium sorbate, propionic acid or a combination of sodium benzoate and potassium sorbate. The untreated samples were unacceptable within 48 h after production. Organic acids, volatile flavor compounds and fermentable sugars were monitored in untreated samples for up to 96 h. Ethanol, 2-methyl-1-propanol, 2-methyl-1-propanal, 3-methyl-1-butanol, 3-methyl-1-butanal, acetone, acetoin, lactic, succinic and formic acid increased significantly within 48 h. Pyroglutamic and pyruvic acid decreased and then increased, while uric acid and sugars decreased within 96 h. Sodium benzoate, potassium sorbate or their combination extended the shelf-life of the control samples by four days. Pasteurization at 97C/10 min reduced the total mesophilic bacteria, lactic acid bacteria, yeasts and Enterobacteriaceae counts to nil and maintained the pH, titratable acidity, specific gravity, and total soluble content constant, and the products were mildly acceptable during storage for up to 60 days. Pasteurization alone was comparable to the combined effects of pasteurization and treatment with preservatives on the quality of the product. Pasteurization alone may therefore be appropriate for small-scale production and increased commercialization.

Notes: Soy protein concentrate (SPC), an extender, is a common additive in ready-to-eat (RTE) meat products. SPC contains antioxidants that could potentially interfere with the ability of ionizing radiation to eliminate Listeria monocytogenes from RTE meat products. When L. monocytogenes was inoculated into cooked beef bologna emulsion containing 0, 1.75, or 3.5% SPC the gamma radiation D10 values, at radiation doses of 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0 kGy, were 0.66, 0.68, and 0.71kGy, respectively. Soluble antioxidant power, as determined by the Ferric Reducing Antioxidant Power (FRAP) assay was 1958, 3572, and 5494 mol in bologna emulsion containing 0, 1.75 and 3.5% SPC, respectively. Soluble antioxidant power was not affected by ionizing radiation. SPC did not prevent ionizing radiation induced lipid oxidation as determined by Thiobarbituric Acid Reactive Substance (TBARS) assay. Hunter color analysis of both unirradiated and irradiated bologna slices containing SPC indicated decreased a value as a result of irradiation, while the addition of SPC helped maintain b-value and L-value. The inclusion of SPC did not represent a barrier to ionizing radiation pasteurization of fine emulsion sausages for the parameters examined.

Notes: The objective of this analysis was to determine the costs of the development and implementation of HACCP, SSOP's, Salmonella Performance Standards, and Generic E. coli Process Control Testing for small meat and poultry plants. USDA estimated these costs to be $0.0024 per pound with the release of the Pathogen Reduction Ruling. Weighted averages from two other studies estimating implementation costs were $0.0005 and $0.0139 per pound. To collect data and measure actual implementation costs, phone surveys and personal interviews were conducted with small meat (defined as having 10 or more employees but less than 500) slaughter and processing plants in North Dakota, South Dakota, Nebraska, Kansas, Missouri, and Oklahoma. The analysis suggests that the plants incurred an average of $0.009 per pound in development and implementation costs for these regulations.

Notes: The objective of this study was to determine if a single assay protocol could result in the concurrent detection of Escherichia coli O157:H7 and Salmonella from a single sample grown in a single enrichment in 24 h. Twenty-five and 375 g of ground beef nonfat dry milk, and dry pet food samples were seeded with low (10 cfu/sample) and high (100 cfu/sample) levels ofE. coli O157:H7 and Salmonella cultures and incubated at 35 and 41C for 18 h for nonselective preenrichment. Incubated samples were analyzed by immunomagnetic separation (IMS) following a 6 h incubation for selective enrichment at 37C using M-broth and enzyme linked immumosorbent assay (ELISA). Depending on the food samples and the inoculation level, the minimum concurrent detection level of E. coli O157:H7 and Salmonella was 〈1 cfu/g in the samples at the competitor flora level of 105 cfu/g or less in ground beef samples, but in other cases of higher competitor loads and low target inoculations E. coli O157:H7 could not be detected in the presence of the Salmonella.

Notes: Risk assessment and impact of foodborne pathogens on the health of different populations was one of the goals identified in the Presidential Food Safety Initiative three-year plan. This entailed estimation of dose-response relationship for foodborne pathogens to humans, either by feeding studies or from outbreaks. For certain pathogens, such as Listeria monocytogenes and Escherichia coli O157:H7, there are no feeding studies due to ethical reasons, and the results from outbreaks are normally used to estimate the infectious dose. The focus of this review is to compile dose-response information in volunteers for several foodborne pathogens including Salmonella, Shigella spp., Campylobacter jejuni, Vibrio spp., Escherichia coli, Cryptosporidium parvum and Entamoeba coli. The infectious dose for different serovars of Salmonella and strains of E. coli was quite large (〉 105 organisms), while the infectious dose for some Shigella spp. seemed to be as low as less than 10 organisms. Toxigenic V. cholerae (O1 and O139 serotypes) were infective at a dose of 104 organisms; a non-O1 strain was infective at a much higher dose (106 organisms). C. jejuni, C. parvum and Entamoeba coli appeared to have infectious doses as low as 500 organisms, 10 oocysts, and 1 cyst, respectively. The infectious dose and the dose response are dependent upon the strains used, and the age and physical condition of the individuals, and can therefore show wide variations. In addition, since many of the volunteer studies are carried out by feeding the organisms in a nonfood matrix after neutralizing the stomach acidity, results obtained may not reflect the true dose response.

Notes: The influence of chlorine or hydrogen peroxide treatment on populations of Escherichia coli 25922 on the external surface of inoculated cantaloupe was investigated. Surface treatment with 70% EtOH, followed by immersion in 108 CFU/mL E. coli inoculum deposited an average of 4.4 log10CFU/cm2 cell population on the cantaloupe surface. The efficncy of washing inoculated cantaloupe was dependent on storage interval between inoculation and treatment. Dipping the cantaloupes in solutions containing 1000 mg/L chlorine or 5% peroxide for 5 min, within 24 h of inoculation, caused a 2 log10 CFU/cm2 reduction of the indigenous surface microflora and a 3–4.0 log10 CFU/cm2 reduction in E. coli. The efficacy was less when the interval between inoculation and treatment exceeded 24 h. Chlorine appeared in be a better antimicrobial agent than hydrogen peroxide against F. coli ATCC 25922 inoculated on cantaloupe surfaces while hydrogen peroxide was better in reducing surface microflora of cantaloupe.

Notes: Consumption of chicken products has been increasing. Most of these products in Finland are sold as fresh marinated pieces in consumer packages. The impact of marination on the survival of enteric pathogens is not known. We studied the survival of Campylobacter jejuni on marinated chicken drumsticks and sliced breast strips stored at a refrigerator temperature of +4C. The marinade was an emulsion of vegetable oil and water with spices, NaCl (5.9% wt/wt) and its pH was adjusted to 4.5 with lactic and acetic acid. The survival of C. jejuni was similar in marinated and nonmarinated chicken drumsticks and strips. The organisms were detected for at least nine days at the higher inoculum level (101– 102 CFU/mL) and for at least five days at the lower inoculum level (101– 102 CFU/mL). C. jejuni, inoculated into plain marinade and stored at 4C, was detected after 24 h but not after 48 h. Our results revealed that marination procedure used to reduce and prevent the growth of spoilage organisms does not significantly decrease the survival of Campylobacter jejuni in chicken products.

Notes: The heat resistance of a Salmonella composite of serotypes Typhimurium, Enteritidis, Montevideo, Mbandaka, Heidelberg and Thompson was evaluated in ground chicken breast meat using an end-point procedure in pouches. A 7D process for Salmonella in chicken was approximately 3 s at 160F (71.1C) with a z-value of 10.3F (5.7C). The data presented here may help cooked chicken products manufacturers design safe processes that meet the USDA Food Safety and Inspection Service performance standard.

Notes: Fourteen fungal species belonging to five genera, Aspergillus, Cladosporium, Penicillium, Fusarium and Scoplariopsis were isolated from the surface of mango fruits, (Mangifera indica L.) variety “Zebda”. Mycotoxin production by isolated molds was tested in Czapek-Dox broth as well as mango pulp. The irradiation decimal reduction doses (D10 values) of the molds were determined in either physiological saline solution or mango pulp. The effects of ionizing radiation in combination with hot water-dipping (55C/5 min) on shelf-life extension and the microbiological, chemical, rheological and organoleptic properties of mango fruit (at mature green stage) stored at 12°C and 80–85% relative humidity were determined. Results showed that Zebda mango irradiated with doses of 1.0 kGy can be stored 50 days at 12°C without any undesirable changes to measured nutrient and sensory quality when compared to unirradiated mangoes refrigerated for 25 days.

Notes: Foodborne pathogens often tolerate and survive environmental stress conditions including extreme acidity to varying degrees. One possible reason for this survival may be the production of protective stress proteins during acid shock (ASR) and/or tolerance (ATR) responses. The ASR and ATR of Listeria monocytogenes strains V7, V37 and CA in tryptic soy broth without dextrose acidified with lactic acid were studied. Possible cross-protection of acid adapted cells against an activated lactoperoxidase system was also determined. The strains were either directly challenged at pH 4.0 and 3.5 to study their ASR or initially adapted at pH 5.5 for the equivalent of 1 generation before challenging at pH 4.0 and 3.5 to study their ATR. Adapted and nonadapted cells were challenged at pH 4.5 with or without an activated lactoperoxidase system. In all cases viability was determined by enumeration over a period of 24 or 48 h after challenge and the production of stress proteins analyzed by 2-dimensional gel electrophoresis. While there were some differences in the survival responses for each strain, the acid adapted cells of each strain survived to a greater degree than nonadapted cells at both pH 4.0 (at least 10 fold at 24 h) and pH 3.5 (at least 1000 fold at 6 h) but not at pH 4.5. The acid adapted cells exposed to the lactoperoxidase system survived better (at least 5-fold) than their nonadapted counterparts for all 3 strains at 24 and 48 h. The 2-dimensional gel analysis for all 3 strains showed that the adapted and nonadapted cells underwent a change in their physiology, (at pH 4.0 compared to the control at pH 7.0; at pH 4.5 with the addition of lactoperoxidase system components) in that there was induction as well as repression of several proteins.

Notes: The prevalence of some enteric bacteria in alfalfa sprouts obtained from public markets and supermarkets in Queretaro City was determined. In addition, the antimicrobial effect of several commercial germicides was tested on alfalfa sprouts for reduction of native coliforms and inoculated Vibrio cholerae Ol or Salmonella typhi. Escherichia coli and Salmonella sp. were detected in 74% and 1.1% of 90 of samples, respectively, and no sample tested positive to V. cholerae Ol. Coliforms ranged from 7.3 to 8.5 log10 CFU/g. Treatment of alfalfa sprouts with 200 mg/L of hypochlorite, of a commercial iodophor, or of chlorine dioxide, or with 100 mg/L of Citricidal® for 5 min, reduced native coliforms only by 1–2 log10 CFU/g. Reductions of S. typhi and V. cholerae O1 with 200 mg/L of sodium hypochlorite and 100 mg/L Citricidal® were also no more than J.5 log10 CFU/g. Sprouts from seeds contaminated with V. cholerae O1 that were irrigated daily with water containing 100 mg/L chlorine dioxide, showed significantly lower V. cholerae Ol counts than seeds irrigated with tap water (p〈0.05). However, V. cholerae O1 persisted after 8 days of sprouting, when the sprouts are ready for marketing. Treatment of seeds and sprouts with antimicrobials does not appear to be effective for reducing pathogens to safe levels.

Notes: The effects and interactions of heating temperature (5–62.5C), pH (4 – 8), NaCl (0 – 6%, w/v), and sodium pyrophosphate (0 – 0.3%, w/v) on the heat resistance of a four strain mixture of Escherichia coli O157:H7 in beef gravy were examined. Thermal death times were determined using a submerged coil heating apparatus. The recovery medium was plate count agar supplemented with 1% sodium pyruvate. Decimal reduction times (D-values) were calculated by fitting a survival model to the data with a curve fitting program. The D-values were analyzed by second order response surface regression for temperature, pH, NaCl and sodium pyrophosphate levels. The four variables interacted to affect the inactivation of the pathogen. Thermal resistance of E. coli O157:H7 can be lowered by combining these intrinsic factors. A mathematical model describing the combined effect of temperature, pH, NaCl and sodium pyrophosphate levels on the thermal inactivation of E. coli O157:H7 was developed. The model can predict D-values for any combinations of temperature, pH, NaCl and sodium pyrophosphate that are within the range of those tested.

Notes: Croquette is a prepared food made with meat or fish as its basic ingredients. Since it is a perishable, heavily handled product, microbiological hazards are associated with the process. Microbiological analyses were performed throughout the commercial processing of chicken croquettes to evaluate the microbial hazards. Moderately high levels of microorganisms were observed in raw materials, but the highest plate counts were noted following extrusion of the croquettes. Pathogenic bacteria, such as Clostridium perfringens, were detected during the process. The increase in the levels of microorganisms observed after extrusion and the presence of C. perfringens were associated with the semi-solid paste called bechamel. Rapid cooling of the bechamel was critical to avoid microbial proliferation and represented an effective critical control point for the implementation of a HACCP program in the processing of croquettes.

Notes: When ozone (1.3 mM) was bubbled for 3 min in a mixture of shredded lettuce and water, counts ofmesophilic andpsychrotrophic bacteria decreased 1.4 and 1.8 log10 cfu/g, respectively. Counts of these microorganisms on lettuce, from a different batch, decreased 3.9 and 4.6 log, respectively, during 5 min of ozone treatment. Shredded lettuce was treated with gaseous ozone, or mixed with aqueous solution of ozone (1:20 w/w) with or without bubbles. For effective delivery of ozone, stirring (low and high speed), sonication or stomaching was applied during the ozonation. Washing the lettuce with water only decreased total count on shredded lettuce by 0.74–1.0 log cfu/g. When lettuce in a treatment chamber was flushed with gaseous ozone, the total count decreased 0.85 log cfu/g, but when vacuum was applied before the ozone flush, the total count decreased 0.96 log cfu/g. Bubbling ozone in water-lettuce mixture while sonicating, high-speed stirring, or before stomaching inactivated 1.4, 1.9 and 1.9 log cfu/g, respectively. In conclusion, bubbling gaseous ozone in water is the most effective ozonation method. Efficient ozone delivery to microorganisms on lettuce requires a combination of ozone bubbling and high-speed stir.

Notes: Fresh pink salmon (Oncorhynchus gorbuscha) fillets and whole Pacific herring (Clupea harengus pallasi) were stored for two weeks at 10C to determine if significant amounts of histamine were produced before the fish spoiled. Spoilage odors in salmon were moderate by day 4 and intense by day 7, while herring had detectable spoilage by day 4 and became potent by day 6. Aerobic bacterial counts increased from 4.0 × 102/g initially to 3.6 × 108/g in salmon fillets by day 14 and from 2.3 × 103/g initially to 2.7 × 107/g in whole herring by day 14. Total volatile nitrogen increased from 1.8 to 78.5 mg N/100 g in salmon and 2.2 to 23.6 mg N/100 g in herring. Histamine was not detected in salmon, while concentrations reached 54.9 ppm in herring at day 14. However, herring were considered spoiled by day 6.

Notes: This report presents results of the investigations carried out to understand the role of fat levels in fish on postirradiation recovery/survival and growth of four pathogens generally encountered in seafoods. Fish of low [golden anchoy, (Coillia dussumierij, 0.39%] as well as high fat [Indian sardine, (Sardinella longiceps), 7.1 %] content (with endogenous biota were inoculated separately with cells of Listeria monocytogenes 036, Yersinia enterocolitica 5692, Bacillus cereus and Salmonella typhimurium; and irradiated at doses of 1 and 3 kGy. The number of viable organisms for each was monitored for two weeks at 2-4C on appropriate selective media. The four pathogens studied exhibited variation in their ability to recover from radiation damage as evidenced in terms of lag period; but their recovery and subsequent growth was not influenced by the fat levels offish. No increased growth of any of the pathogens tested was evidenced in irradiated fish, when compared with nonirradiated one.

Notes: Sporulation temperature is one of the most important factors that determine the heat resistance of spores. Bacterial spores are usually more heat resistant when they are formed at higher temperatures. Sporulation temperature also influences the effect of pH of heating menstruum and the effect of different acids on spore heat resistance. Heat resistance is maximum at neutral pH and decreases with acidification, but when spores are sporulated at high temperatures the effect of acidic pH on heat resistance is lower at high heat treatment temperatures. Lactic and acetic acid decrease spore heat resistance more than other acidulants, but only when spores had been sporulated at high temperatures. These effects should be considered by canning factories of acid/acidified foods, especially in hot climate areas, where these high temperatures can be easily reached. The level of mineralization of spores obtained at different Sporulation temperatures seems to be the most important mechanism responsible for their heat resistance.

Notes: Consumer knowledge of safe handling guidelines and their reported practices assessed by a mail survey indicated consumers considered themselves informed about food safety, and most reported taking action to minimize risk from potential hazards. However, most responses were related to nutritional changes, and 20% indicated they did not know how to reduce risks from microbiological hazards. Consumers were knowledgeable about appropriate safeguards in selection and cooking specific foods, however mistakes were reported in temperature control and handling leftovers. Consumer Reports, university scientists, health professionals and science magazines were considered ihe most reliable source of food safety information. Industry advertisement appears to raise consumer concern in some areas. Educational intervention should emphasize the importance of temperature control and sanitation rather than taste to determine safety. Consumers should receive information about protective technologies like heat and irradiation pasteurization.

Notes: Results from two consumer surveys are presented. In the first, a EU FAIR (European Union Food, Agriculture and Industrial Research Programme), supported project, three-thousand consumers (500 in each of six countries, Germany, Italy, Britain, Spain, Sweden and Ireland) were surveyed in March 1997 on their attitudes to the quality and safety of three meats, beef, pork and chicken. This paper deals with the safety aspects of the survey. Many consumers in all six countries said they were eating less beef and more chicken. Overall, the Spanish and Irish appeared to be the most concerned about the safety of meat, the British were somewhat less concerned. While many were confident that the food in shops is safe, there was a sizeable minority who believed the contrary. When looking for information on the safety of meat, butchers, whether independent or in supermarkets, are the group most trusted by consumers. In terms of consumer concerns, about 60 percent of beef consumers were very concerned about hormones, BSE (Bovine Spongiform encephalopathy), antibiotics and bacteria. Pork consumers had similar levels of concern as beef consumers about bacteria, antibiotics and hormones. For chicken there was a higher level of concern about bacteria (Salmonella) (68% were very concerned) and similar levels of concern to pork and beef for the other issues. Generally, fat was the issue of least concern for all three meats. Freshness was considered to be relatively the most helpful of 7 factors used for assessing safety of meat. The country of origin and what the animal was fed were also considered to be relatively helpful. Factors considered to be relatively less helpful were price and the name of the producer. In the second study, over 1200 pre-leaving certificate Irish school children participated in autumn 1996 in a national survey assessing young people's attitudes to meat. Half of the respondents agreed with the view that eating beef means increasing the risk of getting CJD (Creutzfeldt-Jakob Disease). Those who agreed were more likely to be less frequent eaters of beef and to have reduced their meat consumption in the post-BSE period. It was found also that females were more likely to eat less meat than males and to have reduced beef consumption. The implications of some of the findings of these two surveys are discussed.

Notes: Bovine spongiform encephalopathy (BSE) belongs to a distinct group of transmissible degenerative encephalopathies (TDE) that includes scrapie in sheep and Creutzfeldt-Jakob disease (CJD) of humans. These fatal neurological diseases are caused by unconventional but uncharacterized transmissible agents that have a number of unusual properties; this includes a high degree of resistance to inactivation. The only disinfectant that appears to be completely effective against high titres of TDE infectivity is sodium hypochlorite. Exposure to 1 to 2 M sodium hydroxide has a substantial but incomplete effect, as does autoclaving at temperatures between 132 and 138C for up to an hour; however, a combination of 2 M sodium hydroxide and autoclaving, even at the more modest temperature of 121C for 30 min, appears to be completely effective. With lower titres of infectivity, less rigorous regimes may be effective. For example, although most of the rendering procedures used to manufacture meat and bone meal (MBM) throughout the European Union (EU) have been found to be incapable of inactivating BSE and scrapie agents, one method which appeared to be effective with moderate titres of BSE and scrapie agent, involved exposure to steam at 133C for 20 min. This procedure is now the only one approved within the EU for the manufacture of MBM for feeding animals, excluding ruminants; however, the UK has introduced a ban on feeding MBM to any farmed species because of the occurrence of a new variant form of CJD in the UK which appears to have been caused by the BSE agent. Although the clinical signs of scrapie in sheep are entirely attributable to neurological dysfunction, tissues such as spleen and lymph nodes are known to become infected before those of the central nervous system. In contrast, the only tissues which have been found to become infected in cattle with natural BSE are brain, spinal cord and retina. These are no longer used in animal or human foodstuff. Because scrapie agent has no known association with human disease there has been no restriction in the past on using any sheep tissues, including brain, as human food; however, it is known from experimental studies that the BSE agent can infect sheep by the oral route to cause a disease that is clinically and neurohistopathologically indistinguishable from scrapie. It is also known that the spleen becomes infected in such sheep. Sheep in the UK could theoretically have become infected with the BSE agent through the feeding of infected MBM before the feed-ban in 1988. There are now measures in place that prevent the head, spinal cord, and spleen of sheep being incorporated into foodstuff.

Notes: Considerable time, regulation and consumer concern is associated with the question of chemical residues in food. Potential residues in food span a broad range from natural contaminants (mycotoxins) through environmental contaminants (dioxins, PCBs), agrochemicals (nitrates, pesticides), veterinary drugs (anthelmintics, antibiotics), prohibited substances (hormonal growth promoters), chemicals arising in processing (nitrosamines), packaging components (plasticisers) to contaminants arising in domestic food preparation (heavy metals). The occurrence or avoidance of these chemicals as residues in food is to a greater or lesser extent under the control of the food producer, processor and consumer in the activities of growing/producing, treating, storing, processing, packaging and cooking. The fundamental question is to what extent do or can residues in food constitute a food safety hazard for the consumer. Many of these substances are regulated as to their use and as to their acceptable levels in food while others, by their nature, arise as more random occurrences and, as such, are less prone to regulation. Of particular concern to the producer, processor and retailer of food is what steps may be taken to ensure that the food supply is safe. Best practice in plant and animal husbandry by the producer, in sourcing of material and in control of food manufacturing by the processor, and in sourcing of food products by the retailer combine to assure the safety of food to the consumer. This paper describes the various classes of chemicals which can arise as residues in food, particularly agrochemicals and veterinary drugs, the usage patterns which decrease/increase the likelihood of the occurrence of residues at unacceptable levels, how and in what form(s) residues can occur in foods, and the contribution of food processing to a reduction or otherwise of residue levels in food consumed. Consideration will be given, also, to quantifying the risk posed by chemical residues in food and to a study of the results from a Residue Database and from residue monitoring/surveillance as an indicator of risk to the consumer.

Notes: This paper is concerned with processes and procedures involved in the contamination of beef, lamb and pork carcasses during slaughter. The hides of beef and the fleece of sheep are major sources of carcass contamination. The spread of pathogens from beef hides to the carcass, operatives and surfaces in the abattoir is demonstrated. Efforts to clean the hide of cattle and the fleece of sheep are outlined, with reference to the success of these treatments in reducing carcass contamination. The effect of bringing very dirty or dungy animals to slaughter is considered in terms of the effect on carcass contamination after slaughter. The influence of tying the bung (or rectum) in reducing carcass contamination is discussed, as is the use of plastic bags as an additional control in preventing pathogen spread on pig carcasses. The relationship of this revised procedure in reducing the occurrence of yersiniosis in Norway is shown. The use of a commercially automated system to tie beef bungs is discussed in relation to reducing carcass contamination. A comparison between the removal of faecal contamination on carcasses by trimming or using a new steam-vacuumized system is presented. The effect of preevisceration washing of beef carcasses is described and the rationale relating to bacterial removal using this treatment is discussed. The influence of evisceration as a source of carcass contamination is demonstrated in relation to sheep slaughter. The processes of carcass decontamination using washing with water at different temperatures, steam pasteurization and hot lactic acid are compared in relation to their ability to remove bacteria from beef carcass surfaces. Finally, the effect of line speed and the impact of technology advances on beef and sheep carcass contamination is reviewed.

Notes: During the last few years there is a growing feeling in the Dutch livestock and meat industry that it is essential to change from a product oriented to a more market-oriented production (from quantity to quality). This is mainly due to developments such as a more intense international competition, stagnant or declining meat consumption and negative pressure on the consumers’ image of meat. Counteracting these developments is only possible if every part of the production chain contributes (in close cooperation with each other) to achieve a better control of the whole production process: from conception to consumption. For a number of years an extensive research program has been carried out to set up a system of Integrated Quality Control (IKB). This has led to a “total quality concept” which includes the safety and quality of the product, the production method, care for the environment, and human and animal health. This paper discusses the basic elements (structure and content) of this quality concept. The extent of implementation of the IKB-concept depends on the particular sector, but it is at around 70% for pigs and broilers. For IKB in veal, current participation is over 90%.

Notes: The need for residue testing and controls basically derives from two imperatives, the safety of the food supply and requirements imposed in trade. Maximum residue limits (MRLs) for pesticides, veterinary drugs, intentional food additives and potential contaminants, such as mycotoxins, are set for various food commodities based on toxicological assessment. Regulatory testing on domestically produced goods reveals the prevalence of a particular residue in a specific food commodity and also serves as a means to assess the effectiveness of the product registration system, while testing conducted on imports is primarily a verification of the effectiveness of the regulatory program in the exporting country. For industry, testing is required to demonstrate due diligence or to ensure that a product meets the specifications of an export market or a specific contract. Testing programs should be appropriate to meet the intended use. A survey to determine incidence of violations requires a test that detects residues above the MRL, while a dietary exposure study requires methodology that detects residues with the maximum achievable sensitivity. Tests conducted to certify a product for export or to fulfill the requirements of a contract should ensure that the product is in compliance with the market or contract requirement. If the requirement is “no detectable residues”, a very sensitive test method may be required. In many countries, there is a developing consensus that while government has a role in conducting work that is in the public interest, such as ensuring the safety of the food supply within a level of statistical assurance, it is ultimately the producer of the food who is responsible for the safety of the product or for ensuring that the product meets market or contract requirements. Various aspects of this changing regulatory, trade and consumer environment will be considered, with examples of the roles now played by governments and industry to ensure the safety and quality of food products.

Notes: A simulation model that assesses the risk of acquiring salmonellosis from consumption and handling of chicken was created in an Excel™spreadsheet and was simulated using Risk™. The model simulated the distribution, preparation, and consumption of 1,000 chickens and was designed to determine the relationship between the level of Salmonella contamination on chickens at the processing plant exit and the risk of salmonellosis for consumers of the chickens. A scatter plot of the probability of acquiring salmonellosis from consumption of the chickens simulated versus the Salmonella load on the chickens at the processing plant exit clearly showed that highly (i.e., 〉 100 Salmonella/bird) contaminated chickens at the plant exit did not necessarily pose greater risk of salmonellosis than lightly (i.e., 〈 10 Salmonella/bird) contaminated chickens at the plant exit. Rather, greater risk of salmonellosis was realized from lightly contaminated chickens when they were temperature-abused, undercooked, and consumed by someone from the high risk population.

Notes: Transmissible Spongiform Encephalopathies, or Prion diseases, are fatal neurodegenerative diseases that affect both humans and animals. Examples include Creutzfeldt-Jakob disease (CJD) in humans, Bovine Spongiform Encephalopathy (BSE) in cattle and scrapie in sheep and goats. They are characterized by a long incubation period, ranging from months to years, and a variable length clinical course, both determined by the particular infection and the species involved. Some 170,000 cattle in the UK have been diagnosed with BSE and have been destroyed. In the rest of Europe there have also been cases of BSE, though the numbers involved are much lower. The recent potential link between BSE and a new variant form of CJD has highlighted the importance of controlling both BSE and scrapie in Ireland. Control of the disease in both cattle and sheep is complicated by the long incubation period, the lack of suitable tests and the general lack of detailed information in relation to the biology of the disease. Factors that must be considered in designing an effective control strategy include (1) better understanding of the epidemiology of the disease, (2) developing rapid and reliable tests for the disease, (3) introducing a suitable surveillance system for both BSE and scrapie, (4) minimizing the consequences for farmers that have BSE-infected animals, and (5) implementing and monitoring legislation to prohibit the spread of potentially infectious material. Each of these areas is discussed and it is proposed that the introduction of best available technology in both the diagnosis and surveillance of the national herd could form the basis for an effective program against animal prion diseases.

Notes: This paper describes an outbreak of E. coli O157:H7 that occurred in central Scotland. Edipemiological and microbiological evidence has indicated that the outbreak was comprised of several separate but related incidents, relating to the lunch (attended by around 100 people) held in Wishaw Parish Church Hall, a birthday party held in a public house on November 23, 1996 and retail sales in Lanarkshire and Forth Valley. All isolates of E. coli O157:H7 from individuals in the outbreak belonged to phage type 2 and possessed the verocytotoxin gene VT2. Two hundred sixty-two of these isolates have been subjected to pulsed-field gel electrophoresis (PFGE): all had indistinguishable profiles. There were 496 cases in total. There have been 20 deaths (all adults) associated with the outbreak, the highest number of deaths associated with an outbreak of E. coli O157:H7 infection in the world. Of these, 8 people had attended the luncheon served at Wishaw Old Parish Church on November 27, 1996. The age range of those who died was 69 to 93 years. The outbreak was investigated by the Pennington Group who concluded that the circumstances of the central Scotland outbreak, and the inevitable uncertainties that may surround outbreaks generally, provide strong justification for the precautionary, preventative measures proposed and the recommendations made.

Notes: Judges rated the intensity of NaCl solutions and orange drinks of varying sweetness using category scales and line scales. They performed under four response conditions that varied in reliance on memory: (1) verbal response (2) written response with no retasting and the response sheet removed (3) written response with a single response sheet which allowed past scores to be reviewed and amended but with no retasting (4) the same as ‘3’ but with retasting. Discrimination errors decreased from conditions ‘1’ through ‘4’ indicating how allowing judges to ‘refresh the memory’ improved discrimination. The cognitive processes involved in rating and consequences for scaling protocols and the experimental design for descriptive analysis are discussed in the light of these findings.

Notes: The effects of sweetener type, sweetener concentration, and fruit flavor on the sensory attributes of soy fortified yogurt were determined. Soy fortified dairy yogurts were made by the addition of soy protein concentrate (0, 2.5, 5%) to standard yogurt mixes prior to fermentation. Sweetener type (sucrose, fructose, sucrose/fructose) and sweetener concentration (6, 8, 10%) were incorporated into yogurts in a split plot experiment with soy concentration as a subplot factor. Flavor effects (plain, lemon, strawberry) were studied in a 3 × 3 factorial experiment (soy concentration × flavor). A trained descriptive panel (n=13) evaluated yogurts for seven flavor and aroma terms. Sweetener type had no effect on sensory properties with the exception of perceived sweetness. Soy flavors and astringency decreased with increasing sweetener concentration. Fruit flavors decreased soy aromas, soy flavors, and astringency in yogurts containing soy protein. These results indicate that sweetener concentration and fruit flavors play a crucial role in formulating yogurts fortified with soy protein.

Notes: A two-part study determined the effectiveness of gum-based rinses with or without oil for alleviating residuals of a bitter (0.8 g/L caffeine solution) and an astringent (1g/L alum solution) stimuli in serial responses using a sip and spit method. In Experiment 1, rinsing with deionized water was compared to rinsing with 0.3% xanthan gum in water alone or with 5% corn oil and 0.55% carboxymethyl cellulose (CMC) in water alone or with 5% or 10% corn oil. The 0.3% xanthan gum and 5% corn oil mixture resulted in the highest stimulus intensity difference before and after rinsing, whereas 0.55% CMC had a value of nearly zero for residual effect. Results of a two-alternative forced choice test used in Experiment 2 indicated that both were equally effective for reducing bitterness residuals, but 0.55% CMC solution resulted in the lowest (p=0.007) residual effect for astringency. Therefore, the 0.55% CMC rinse was considered an effective interstimulus rinse to use for assessing both bitterness and astringency in model solutions.

Notes: For discrimination tests not requiring the nature of the difference to be specified in the instructions, such as the triangle, duo-trio and same-different protocols, it is usually assumed that the decision rule used by the subject in order to generate an answer involves the comparison of the relative sensory distances between the samples. However, there is evidence that an alternative cognitive strategy, the β-strategy, involving the absolute categorization of the sensations could be used by the subject when performing these protocols. This paper introduces the characteristics of this alternative strategy by discussing its statistical power (higher than the traditional strategies) and by describing means of investigating which strategy is used by the subject during an experiment as well as illustrating the experimental conditions that might facilitate the use of this particular decision rule.

Notes: The perception of astringency and basic taste in mixtures and their interaction effects were investigated by two procedures. In Experiment 1, focused and nonfocused testing procedures were compared using mixtures of low and high concentrations of alum and basic taste solutions. Both procedures yielded taste and astringency intensities that were modality-dependent. Nonfocused testing was used in Experiment 2 to investigate the interactions of astringent phenolic (tannic acid) and nonphenolic (alum) compounds with each basic taste. Sweetness of sucrose increased with increased concentration with or without alum or tannin present. Changes in salty, bitter, and sour taste intensities were modality-dependent. Astringency either remained unchanged or decreased with the addition of sucrose, sodium chloride, citric acid, or caffeine depending upon the taste concentration. Bitterness of tannin and alum at high concentrations was suppressed by the addition of sucrose, sodium chloride, or citric acid; sourness also decreased in the presence of sucrose or sodium chloride as well as a high level of caffeine.

Notes: Principal component similarity (PCS) analysis was used to evaluate judge performance from a wine competition. Data were analyzed for five international judges and seven wine makers, for 42 white, 30 red and 25 specialty wines, using a 20-point quality scoring system. Principal similarity plots were used to group judges according to judging 'style’ and to identify outliers, for each wine category. Judge groupings were consistent when three different references were used; however, the most interpretable PCS plot was obtained when the overall mean-judge-score was used as the reference. Results from PCS were compared to principal component analysis (PCA). PCS analysis allowed the information from all significant principal components to be graphically represented in two dimensions and was more successful in classifying judges than plots based on the first three principal components. The technique of PCS is an important complement to existing methodologies, and can provide wine competition coordinators with an objective technique for judge evaluation and selection.

Notes: Exact tables calculated directly from the probability function of a beta-binomial distribution are provided for replicated difference and preference tests. The tables can be used for small experiments when the numbers of replications and trials are not more than five.

Notes: Dependence among responses in using the A-Not A or “ Yes-No” task are accounted for in new hypothesis testing models. The new models involve adjustments to Pearson's and McNemar's chi-square statistics and to the variance of d', a measure of signal detectability or sensitivity.

Notes: Anecdotal evidence suggests that astronauts’ perceptions of foods in space flight may differ from their perceptions of the same foods on Earth. Fluid shifts toward the head experienced in space may alter the astronauts’ sensitivity to odors and tastes, producing altered perceptions. Our objective was to determine whether head-down bed rest, which produces similar fluid shifts, would produce changes in sensitivity to taste, odor or trigeminal sensations. Six subjects were tested three times prior to bed rest, three times during bed rest and two times after bed rest to determine their threshold sensitivity to the odors isoamylbutyrate and menthone, the tastants sucrose, sodium chloride, citric acid, quinine and monosodium glutamate, and to capsaicin. Thresholds were measured using a modified staircase procedure. Self-reported congestion was also recorded at each test time. Thresholds for monosodium glutamate where slightly higher during bed rest. None of the other thresholds were altered by bed rest.

Notes: The effect of liking, brand and price label on purchase intention were studied on crisp snacks in branded, supermarket own label and economy form. Unlabeled assessment segregated the products into differing levels of liking which did not correspond to marketed price and brand location. Level of liking dominated purchase intention under partial label (price or brand alone) and full label (price with brand) conditions. Relative and derived purchase intention measures gave clearer label effects with significance for brand and price. Consumers who professed higher price awareness were more influenced by price, but those professing brand as a main purchase intention reason gave more weight to liking. Results from analysis of purchase intention and degree of liking measures according to private body conscious level were inconclusive.

Notes: Reaction Time (RT) procedures are widely used in cognitive and behavioral experiments. In the sensory realm RT has been traditionally applied to measure visual, auditory or motor responses. The application of the RT method to gustatory stimuli has proved to be difficult. Attempts to develop automatic control techniques have been restrained by difficulties related to the control of variables, e.g. physiochemical characteristics of chemical solutions and the procedure for stimulus presentation. In this report we describe a computer based system that was designed to measure the reaction time to taste solutions dropped on the tongue. The equipment consists of a pumping system, an interface between the computer and the pumping system, the software required to control the interface and to measure reaction time, and a push button to detect the subject's response. The system can be used as a tool for both research and evaluation tests.

Notes: Caffeine contributes to the flavor profiles of beverage and food products, and other bitter compounds, such as quinine, cannot replicate caffeine's bitterness. Research also has indicated caffeine's ability to enhance desirable tastes, such as sweetness and saltiness, in beverages by modifying neurological pathways. Caffeine may reduce potential “ off-flavors” by solubilizing some compounds, while having little effect on other compounds considered important in beverage flavor profiles. Exposure to caffeine may enhance cognition and potentially heighten the capacity for smell and taste. Thus, use of caffeine in beverages may positively affect flavor profiles and the experience of beverage consumption.

Notes: Commercial production of catfish requires frequent feeding, which contributes to effusive microbial blooms in ponds. Microbial production of the muddy metabolite 2-methylisoborneol (MIB) can reduce fish flavor quality. Although commercial seasonings may be added to fillets, little information is available concerning the sensory interaction of seasonings and MIB. The replicate sensory evaluation of catfish fillet samples containing either 1.0 or 10.0 ppb chemically-synthesized MIB conducted under controlled conditions indicated a more frequent acceptance of fish as on-flavored in samples treated with a “ lemon-pepper” commercial seasoning preparation than either untreated samples or those treated with a “ cajun-spice” seasoning blend. In addition, experimentation conducted with fish containing MIB from biological sources within the production pond, indicated a similar reduction in MIB flavor of lemon-pepper-treated samples. Although a 4-terpenol co-eluted with MIB from lemon-pepper treated samples subjected to gas chromatography mass spectroscopy, the compound(s) in the lemon-pepper preparation that interfere with the perception of MIB was (were) not identified.

Notes: The focus in this study was to study time intensity (TI) methodology and procedures of getting the sensory panel acquainted with this technique. By means of a descriptive profiling exercise effects of altering the structure of a β-lacto-globulin gel, laced with banana aroma on the perception of banana flavor were obtained and a suitable attribute for TI was selected. Samples made up by protein, without any fat are not ideal for a TI study of flavor release because of the fast release of aroma. However, although the concentration of banana aroma was identical in the four groups of gels the intensity was perceived as different. This was reflected in the descriptive profiling as well as in the dynamic study. The TI study showed that it is important to minimize distractive, noncrucial information during the exercise. The assessors had different abilities to connect with the dynamic data acquisition procedure and training made the assessments more congruent. The results also indicate a relationship between the appearance of the TI-curve and the score of the total banana aftertaste.