Microbial Load and the Prevalence of Escherichia coli, Salmonella spp. and Listeria spp. in Ready-to-Eat Products in Trinidad

Abstract

This study was designed to determine the prevalence and microbial load of Listeria spp., Escherichia coli O157 and Salmonella spp. in ready-to-eat products in supermarkets across Trinidad. The microbial load was assessed using the total aerobic plate count (TAPC) per g/ml of foods and prevalence of Escherichia coli O157 and Salmonella spp. determined using conventional methods. For Listeria monocytogenes, immunomagnetic separation (IMS), TECRA (enzyme-linked immunosorbent assay, ELISA) and conventional methods were used. The log 10 mean ± sd TAPC per g or ml was highest for vegetables (11.0±11.6), and lowest for seafood (5.2±5.7) (p < 0.05). The prevalence of L. monocytogenes was 1.7 %. Sixteen (4.5%) of 153 samples yielded E. coli but all samples were negative for Salmonella spp. and E. coli O157. The high microbial load and isolation of L. monocytogenes and E. coli from popular RTE foods could pose a health risk to consumers in the country.