Comparison of bagged oysters for raw consumption and heating on freshness and microbiological contamination

This study compared the freshness (pH) and microbial contamination (sanitary indicative and pathogenic bacteria) in the two kinds bagged oysters which were for heating (HO) and raw consumption (RO). The pH was not significantly (p>0.05) different between HO (6.01±0.18) and RO (6.03±0.13). The total viable bacterial count was 2.61±0.23 log CFU/g for HO and 2.52±0.18 log CFU/g for RO while coliforms, Escherichia coli and Bacillus cereus were not detected in any of the samples (ND: < 10 CFU/g). Enterohemorrhagic E. coli, Campylobacter jejuni, Clostridium perfringens, Staphylococcus aureus, Listeria monocytogenes, Yersinia enterocolitica, Salmonella spp., and Vibrio parahaemolyticus, Vibrio vulnificus, and Vibrio cholerae from any of the samples were all negative. Results indicate no significant difference in freshness or microbial contamination between the two types of bagged oysters. The pH and microbial contamination levels determined in the present study may be used as the primary data to execute microbial risk assessment of two kinds of bagged oysters.