49B-28 |
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E. C. ROSAS-BURGOS, M. S. Yépiz-Gómez, M. Tequida-Meneses, and F. J. Cinco-Moroyoqui. Mexico The shelf life of fish and fish products is negatively affected by the deteriorative changes that marine species undergo during storage. Microbiology of marine food products is fundamental to understanding the quality and safety issues that are important to the seafood industry and consumers. The aim of this study was to determine the level of deteriorative changes and the types of microorganisms that grow in the trigger fish (Balistes polylepis) during its storage on ice. Naturally contaminated fresh trigger fish was stored on ice for 17 days. Samples were taken every three days for measurement of pH, total mesophilic bacteria count, and trimethylamine (TMA) production. Identification of the types of microorganisms present was also performed. The results demonstrated a very close relationship between changes in pH of the product and total mesophilic bacteria (P<0.05). It was observed that the pH varied from 6.23 to 6.07 in the last 7 days of storage (P<0.05) with no significant changes in the first days of the storage. The microbial growth was more evident in the last 7 days of storage (from 990 to 729333 CFU/g). Significant amounts of TMA were detected in the product after 8 days of storage (P<0.05). High correlation coefficients were observed between changes in pH and TMA (r=0.84), pH and total count (r=0.76), and total count and TMA (r=0.86). Identification tests of the type of microorganisms that grow in trigger fish revealed the presence of Pseudomonas putrefaciens and Proteus vulgaris. Pseudomonas was the most predominant genus. It is conclude that the optimal storage time for trigger fish on ice is no more than seven days. Furthermore, determination of changes in pH or TMA are simple useful tools to determine the degree of spoilage of trigger fish during its storage on ice.
Session 49B, Aquatic Food Products: General
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