Purpose: The goal of this study was to investigate the microbiological quality of three seafood species obtained from four retail stores located on the Eastern Shore of Maryland.
Methods: A total of 468 frozen catfish, shrimp, and tilapia imported (60, 85, 84) and domestic (96, 71, 72) samples were analyzed for aerobic plate count (APC), total coliforms, Escherichia coli and three major foodborne pathogens (Campylobacter jejuni, Salmonella, and Vibrio) using standard methods. Presumptive isolates were confirmed using BAX polymerase Chain Reaction. Measurement outcomes were evaluated by one-way ANOVA or t-test when quantitative and by Fisher’s exact test when qualitative.
Results: All samples were positive for APC and the average log CFU/g for APC ranged from 3.9 to 4.1 in the three types of seafood. Total coliforms were found in 41% of the samples and 8.8% were positive for E. coli. Approximately 3%, 27% and 8% of the samples were positive for Campylobacter jejuni, Salmonella, and Vibrio, respectively. With respect to comparisons between imported versus domestic, statistically significant differences in rate of detection of total coliforms were observed in shrimp but there were no statistically significant differences between average log CFU/g for APC or the rate of detection of E. coli. With respect to the major pathogens, there was a relatively large difference between Salmonella prevalence in imported versus domestic tilapia (33.3% of imported and 19.4% of domestic).
Significance: These findings suggest potential food safety hazards associated with imported and domestic seafood and warrant further large-scale studies. Attention should be paid to sanitary and spoilage condition of the seafood.