Bacteriological quality of individually quick-frozen (IQF) raw and cooked ready-to-eat shrimp produced from farm raised black tiger shrimp (Penaeus monodon)

One thousand, two hundred and sixty four samples of individually quick-frozen (IQF) peeled and deveined raw and 914 samples of cooked ready to eat shrimp samples produced from farm raised black tiger (Penaeus monodon) obtained from a seafood unit working under HACCP concept were analysed for total aerobic plate count (APC), coliform count, Escherichia coli, coagulase positive Staphylococci and Salmonella. The overall bacteriological quality of the product was found to be good. Of the frozen raw shrimp, 96% of samples showed APC below 10(5) while 99% of the frozen cooked ready-re-eat samples showed APC less than 10(4). The APC ranged from 1.0 x 10(2) to 4.2 x 10(6) cfu/gm in frozen raw shrimp and from 1.0 x 10(2) to 6.4 x 10(4) cfu/gm in the frozen cooked shrimp. Prevalences of coliforms in raw shrimp and cooked shrimp samples were 14.4% and 2.9% respectively. The coliform count in raw products ranged from 1.0 x 10(1) to 2.5 x 10(3) cfu/gm and in the cooked products, from 1.0 x 10(1) to 1.8 x 10(2) cfu/gm. Although all the cooked shrimp samples were free of coagulase positive staphylococci, E. coli and Salmonella, 1.0, 2.0 and 0.1% of the frozen raw shrimp samples tested positive for coagulase positive Staphylococci, E. coli and Salmonella respectively. The Salmonella strain was identified as Salmonella typhimurium. The results of the present study highlight the importance of implementation of HACCP system in the seafood industry to ensure consistent quality of frozen seafood. (C) 1998 Academic Press Limited.