Microbiological quality of fresh and frozen cultured black tiger shrimp (Penaeus monodon) cultured in Sri Lanka

Abstract

The prevalence of the pathogenic bacteria, Salmonella sp. Vibrio cholerae, Vibrio parahaemolyticus, total conforms, faecal coliforrns and Escherichia coli in cultured shrimp, pond sediments, water and the pelleted feed were analysed. Raw frozen shrimps were also analysed for total plate count, coliforms, faecal coliforms, E. coli, Staphylococcus aureus, Salmonella, Vibrio parahaemolyticus and Vibrio cholerae.In shrimp, water and sediments the total coliform counts were <3- 93 MPN/g, 0-45 MPN/100m1 and 3.6-93 MPN/g, while the faecal coliform counts were <3-15 MPN/g, 0-11 MPN/100m1 and <3-23 MPN/g respectively. E. coil were in the ranges of 0-8 MPN/100 ml (water), <3-9.1 MPN/g (sediment) and <3-7.3 MPN/g (shrimp). In one occasion, feed was highly contaminated with coliforms (>1100 MPN/g), faecal conforms (>1100 MPN/g) and E. coli (460 MPN/g), Salmonella sp were not recovered from samples of shrimp, pond water, sediments and feed. V. parahaemolyticus was detected in farm shrimp, sediment and water at a density of 101-102 cfu/g.The total plate counts for frozen shrimp were 102-107 cfu/g. In 27% samples it ranged from 105 cfu/g to 106 cfu/g while in 59% it was 106- 107cfu/g. The E. coil count of frozen shrimp ranged from <3 to 10 MPN/g with 94% counts less than 3 MPN/g. Vibrio cholerae, Vibrio parahaemolyticus, Salmonella sp. and Staphylococcus aureus were not found in frozen shrimp samples.