ALBERT

Description:    Several rapid and automated microbiological methods have been introduced by food control laboratories because they allow microbiological quality (e.g. contamination with spoilage microorganisms and/or pathogens) of products to be checked or hygiene monitoring undertaken during production. This study evaluated three applications of the TEMPO ® system; an automated method based on the most-probable-number technique, performed in parallel with the relevant ISO standard method for comparison. Escherichia coli certified reference material and soft cheese samples contaminated artificially with E. coli were used throughout the study. Performance characteristics including precision, bias and limit of detection of E. coli (EC), coliforms (TC) and viable aerobic mesophilic microflora (TVC) were determined with particular attention given to low-level contamination, which typically occur in manufacturing and retail as well as storage and consumption at home. TEMPO ® EC was more precise than TEMPO ® TC whilst TEMPO ® TVC showed the most variation. Moreover, higher numbers of E. coli were obtained with TEMPO ® EC than TEMPO ® TC. Reliability of the system depended on the specificity of detection of the targeted group of microorganisms as well on the method. Although, methods like TEMPO ® offer convenience, they often lack the necessary clarity in terms of operational details, measurement principles and data processing necessary for reliable routine use. Installation of an ‘expert modus’ to facilitate access to original data would significantly increase commercial confidence in the application and use of these systems. Content Type Journal Article Pages 1-11 DOI 10.1007/s00769-011-0772-3 Authors U. Zitz, Department of Food Sciences and Technology, Institute of Food Sciences, BOKU-University of Natural Resources and Life Sciences, Vienna, Muthgasse 18, 1190 Vienna, Austria K. J. Domig, Department of Food Sciences and Technology, Institute of Food Sciences, BOKU-University of Natural Resources and Life Sciences, Vienna, Muthgasse 18, 1190 Vienna, Austria A. Hoehl, Department of Food Sciences and Technology, Institute of Food Sciences, BOKU-University of Natural Resources and Life Sciences, Vienna, Muthgasse 18, 1190 Vienna, Austria H. Weiss, Institute of Biometry and Data Processing, Free University of Berlin, Oertzenweg 19b, 14163 Berlin, Germany P-Th. Wilrich, Institute of Statistics and Econometrics, Free University of Berlin, Garystraße 21, 14195 Berlin, Germany W. Kneifel, Department of Food Sciences and Technology, Institute of Food Sciences, BOKU-University of Natural Resources and Life Sciences, Vienna, Muthgasse 18, 1190 Vienna, Austria Journal Accreditation and Quality Assurance: Journal for Quality, Comparability and Reliability in Chemical Measurement Online ISSN 1432-0517 Print ISSN 0949-1775