Cook-serve method in mass catering establishments: Is it still appropriate to ensure a high level of microbiological quality and safety?

The purpose of this study was to evaluate the hygienic quality of three traditional “cook-serve” catering establishments in Lombardy, Italy (with an output ranging from 800 to 1700 meals a day), by monitoring the microbiological quality and safety of foods ready for consumption (n = 727), tap water (n = 32), microfiltered drinking water (n = 28), food contact surfaces (n = 280), and food handlers (n = 76). The food contact surfaces showed unacceptable contamination in 17.1% of samples. The hygienic level of the washed hands of food workers was very high, since only 1.3% of samples showed unacceptable contamination. Food sample analyses highlighted a percentage of samples that did not conform to microbial reference standards: the presence of Listeria monocytogenes was found in 11.5% of “soft cheese” samples. Staphylococcus aureus non-conforming percentages ranged from 2.2% for “first and second courses” to 34.6% for “soft cheeses”; Escherichia coli, from 2.7% for “raw vegetables” to 7.7% for “soft cheeses”; total coliforms from 6.7% for “first and second courses” to 76.4% for “raw vegetables”. The results of the water analysis indicated a high frequency of contamination with Pseudomonas aeruginosa (21.4% for microfiltered drinking water and 21.9% for tap water samples). In conclusion, the results suggest that more effort should be made in the application of HACCP principles. In addition in order to ensure a higher level of microbiological safety of meals, various changes in the timing of food preparation and holding temperatures are needed.