Bacteriological quality of fresh and smoke-dried oysters sold in Creek Road Market, Port Harcourt, Nigeria

Abstract

This study evaluated the bacteriological quality of fresh and smoke-dried oysters (Crassostreagasar) from Okrika fishing port, sold at the Creek Road market, Port Harcourt, found to have high bacterial load. Smoke-drying significantly reduced total aerobic count by 3 log cycles (p< 0.01) from an average of 1.26x10⁹ cfu/g to 1.42x10⁶ cfu/g and average pH value from 6.51 to 5.69. Total coliform and Escherichia coli counts, indices of sanitary quality, were also high but not significantly different for the sample types (p<0.05). Average counts for total coliforms and E. coli were 5.78x10⁸ cfu/g and 2.36x10⁸ cfu/g for fresh oysters respectively compared to 4.1x10⁷ cfu/g and 1.46x10⁷ cfu/g for smoke-dried samples. Bacterial isolates found in fresh oyster were Klebsiella sp. Escherichia sp., Proteus mirabilis, Citrobacter sp., Micrococcus sp., Bacillus sp., Staphylococccus sp. and Serratia sp. while E. coli, Streptococcus sp., Staphylococcus sp. and B. cereus predominated in dried oysters. The oyster meats did not meet the standards of International Commission on the Microbiological Specification of Foods (ICMSF) for raw oysters of 5x10⁵ cfu/g for total aerobic count and 230/100g for E. coli using 5 sampling units and are therefore considered hazardous for export and consumption. However the pH of fresh oyster samples met the proposed standard for freshness of 6.2-5.9 while dried oysters did not.

Keywords: Fresh and dried Oysters, Bacteriological Quality, ICMSF, Port Harcourt