A Preliminary Microbial Survey of Ready-To-Eat Salads at Popular Food Establishments in Trinidad

Ready-to-eat salads are becoming increasingly popular as they combine the healthy characteristics of fruits and vegetables with that of a short preparation time. This study seeks to determine the microbial quality of ready-to-eat salads that are sold in food establishments in Trinidad. A total of 56 samples were collected from two supermarkets and two shopping malls and were analyzed using culture procedures. The total number of aerobic mesophilic bacteria and Escherichia coli colonies were determined for each salad sample. Samples were also tested for Salmonella spp. The average number of aerobic bacteria was 6.3±1.1 logCFUg-1 with a range of 4.3 to 7.5 logCFUg-1. The level of aerobic bacteria in the salad samples was dependent on the food establishment from which it was purchased and varied significantly across food establishments (P<0.001). The shopping malls had higher levels of aerobic bacteria than supermarkets (P<0.001). E. coli was found in 100% of the salad samples analyzed and the level present varied significantly among food establishments (P<0.05). The average E. coli colony count was 3.7±0.7 logCFUg-1 ranging from 2.7 to 5.0 logCFUg-1. Salmonella spp. was detected in 67.86% of the samples analyzed. The number of salad samples contaminated with Salmonella varied significantly during the two periods of testing, week 1 and week 2 (P<0.05). In this study, the researcher only sampled ready-to-eat salads from four of the many food establishments in Trinidad. Due to the high number of: aerobic bacteria and E.coli colonies, and samples contaminated with Salmonella found in the samples analyzed, it was recommended to increase the sample size in order to provide a general overview of the quality of ready-to-eat salads sold in Trinidad.