BACTERIOLOGICAL QUALITY AND MICROBIAL HEALTH RISKS ASSOCIATED WITH FRESH-FROZEN AND DRIED-PROCESSED READY-TO-SELL PRAWNS (MACROBRACHIUM ROSENBERGII)

Abstract

This study set out to determine the bacteriological quality and the microbial health risks associated with ready-to-sell prawns. Fresh-frozen prawns were obtained from supermarkets and dried-processed prawns were obtained from local markets in Akure, Nigeria (n = 120). Levels of E. coli, faecal coliforms, Shigella, Salmonella and Staphylococcus aureus in the samples were determined using standard microbiological methods. Probabilities of infection (P_i) associated with exposure to Salmonella and Shigella were determined using beta-Poisson model and for S. aureus exponential model was adopted. Mean level of Salmonella was 0.9 log₁₀ CFU 100 g^-1 in fresh-frozen prawns whereas mean levels of Shigella in fresh-frozen and dried-processed prawns were 4.4 and 4.5 log₁₀ CFU 100 g^-1 respectively. Probability of infection with exposure to a single CFU of Salmonella, Shigella and S. aureus was predicted at 1.6 × 10^-7, 1.9 × 10^-4 and 7.6 × 10^-8 respectively. This study demonstrates that the levels of bacterial contamination of the prawns and the risks per serving per year were unacceptable.