Investigating the effect of storage temperature and hot-water treatment on the microbial dynamics in edible oyster (Saccostrea cucullata)

Abstract

Oysters are an important sea food all over the world apart from shrimp and crabs. They are usually sold as a live product and can be stored for several weeks before consumption. Temperature abuse during oyster post- harvest handling may allow multiplication of natural spoilage microflora as well as pathogens, which is a potential threat to consumers and/or compromising product quality. In this study, the effect of storage temperatures (25°C, 4°C, 0°C and –10°C) and boiling on the microbial quality of shell stock and shucked meats of oysters (Saccostrea cucullata) were examined. The load of total bacteria, fungi, coliform, fecal coliform, Salmonella sp. and Streptococcus sp. were comparatively higher in shucked meat than in the shell-stock at all the storage temperature (except Vibrio sp.) and number of the spoilage bacteria is directly proportional to the storage time but decreased with lowering of the temperature. Microbial count also observed at various interval of treatment with boiling water (100°C). During boiling water treatment of the shell-stock and shucked meats, decimal reduction time, D-value (D100°C) for total microbes was found to be 2.7 min and 2.4 min respectively. The results indicated that oysters must be stored for a limited time as shell-stock and during cooking it should prepared as shucked meats, and washing with boiled water is a simple method for making it microbes free.