Microbiological Examination of Ready-to-Eat Salads (Crispy Green) from Retail Establishments in the United Kingdom

Abstract

A study of ready-to-eat salads (crispy Green) from retail establishments in the United Kingdom, was undertaken to determine their microbiological quality. The salads were collected and examined according to a standardized protocol. Total count was carried out and all colonies on CFC and MRS were counted as Pseudomonas and Lactobacilli respectively, while yeast and mould counts were obtained from RBCA agar. Only large dark colonies on VRBA agar were counted. E. coli enumeration was obtained from E. coli broth culture to check for acid and gas production which was found to be negative and a confirmatory test was carried out using tryptone water for indole production. This study has shown that there was a level of contamination associated with ready-to-eat salad in the U.K. The APC count was within the acceptable range according to the PHLS Guidelines. No growth of E. coli and Listeria was recorded showing that sample was satisfactory in that respect. For Pseudomonas there was a notable count due probably to the favourable temperature that suites their survival as they have the ability to grow at low temperature. There was also high count for yeast and mould, due possibly to their ability to grow at low temperature, with their optimum at 15-30^oC.