Microbiological quality of ready-to-eat foods: results from a long-term surveillance program (1995 through 2003)

The coordination of food sampling activities across Wales, a part of the United Kingdom with a population of approximately 3 million, led to the establishment in 1995 of a coordinated food-sampling program designed to monitor on a long-term basis the microbiological quality and safety of specific ready-to-eat products. This surveillance system has been ongoing for 9 years and has generated a database of microbiological and associated demographic results for 15,228 ready-to-eat food samples. The food types that had the poorest overall results were sliced meats, unsliced poultry, sandwiches made without salad, and cakes made without dairy cream. For all food types, the overall unsatisfactory rate was 17% for aerobic colony counts, 1.6% for Escherichia coli, and 0.5% for Listeria spp. Overall unsatisfactory or unacceptable rates for pathogens such as Clostridium perfringens, Listeria monocytogenes, Bacillus cereus, and Staphylococcus aureus were all below 0.5%. No Campylobacter-positive samples and only one Salmonella-positive sample were found. The analysis of the results show that the ready-to-eat food types sampled over the 9 years of the program were generally of good microbiological quality when compared with current United Kingdom guidelines. The information contained in the database provides a baseline measurement of the microbial quality of a variety of ready-to-eat foods and allows environmental health officers and food microbiologists to generate hypotheses for targeted surveys or research work.