Publication Date:
2021-05-19
Description:
Fishers need to be aware of problems related to product quality and safety. Improper handling of tunas can cause quality loss. Histamine poisoning of consumers, and loss of investments. In this research, the quality loss of tunas during handling from landing stages to processing plant were determined. Data collected from landing areas in Hormozgan province and canning factory in Qhazvin city, by talking to fishers. Observing handling practices, monitoring time and temperature, and organoleptic evaluation of tunas during different stages of handling. Samples collected from defined grades (A, B, C and D), for Total Volatile Nitrogen (TVN), pH, Humidity, Water Holding Capacity (WHC), Histamine, Total Aerobic Mesophilic and Psychrophilic count analysis. Tunas were caught overnight (during one night) or within several days, by conventional fishing vessels. In overnight catches, the fish is handled on deck with no icing. According to calculated time for fishing and onboard handling, estimated that the fish were kept 4-16 hours at ambient temperature. The average of ambient temperature during warm months (May to October) were 27-280C. During several days catching, the 1ish were iced in insulated tanks and held onboard for 3-5 days before landing. The average temperature of fish body were up to SOC. at landing stage. The variation of fish body temperature showed the insufficient and improper icing of fish. Landing from vessels and loading the fish into the trucks are done by man powers. Landing stages have not any equipment for landing and/or loading. For this reason. These docks must be improved and equipped. The results of organoleptic assessment showed that, for overnight caught Longtial tuna (Thunnus Tenggol), The most quality loss was occured in June compared with other months (62.8% grade A, 35.9% grade B and 1.3% grade C). Also. The same results are achieved for kawakawa (Euthynus affinis). Quality loss was higher in several days catching compared with overnight catching, especially in warm months. During these months, 6.3±5.4% of tunas were grade C. The amounts of grades A and B were 54.8±16.4% and 38.9±16.1 % respectively. Quality assessment of tunas handled to processing plants out of Hormozgan province, showed that, this stage of handling have significant effects on quality loss. Statistical analysis of data showed that the organoleptic evaluation procedure enabled the rapid selection not only of category of freshness of the fish but also of the samples being at the risk of presenting histamine. The average of measured TVN for grades A, B and C were 24.1±2.2 , 29.2±3.7 and 36.8±11.1 mg% , respectively. The means of TVN showed significantly difference between quality categories (P〈0.05). The average of pH for grades, A, B and C were 5.66±0.13 , 5.71±0.14 and 5.81±0.17, respectively. The difference between grades A and C were statistically significant. The average of humidity for grades A to C were 72.7±1.9 72.4±1.8 and the results for WHC were 89.0±2.6 , 86.8±2.2 and respectively. The means of humidity and WHC showed significantly difference between grades A and C. the histamine content of samples from grades A, B and C were 0.68±0.52 131±0.77 and 1.82±0.86 mg% , respectively. One sample from grade D, showed the histamine content of 12.14 mg% . The differences between grades A and C were statistically significant (P 〈0.05). The mesophilic counts of grades A, B and C were 3.7x10 , and 2.3x10 cfu/g. These counts for psychrophilic microorganisms were, and 6.4x10 cfu/g, respectively. Grade C had the highest count of mesophilic and showed significantly difference with other quality grades (P 〈0.05). The differences between psychrophilic count of grades A, B and C were not significant (P 〉0.05). According to results of this research, concluded that, tuna handling condition and procedure in country is improper and needs improvements. Several practical recommendations for improve the quality and safety of tunas are presented.
Description:
Iranian Fisheries Science Research Institute
Description:
Published
Keywords:
Tuna
;
Conventional fishing
;
Cold chain
;
Quality loss
;
Histamine
Repository Name:
AquaDocs
Type:
Report
,
Refereed
Format:
93pp.
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