Microbiological quality assessment of meals and work surfaces in a school-deferred catering system

Microbiological contamination is one of the main parameters that must be assessed to assure the safety of foods produced by a catering system. The aim of this study conducted between 2011 and 2015 was to assess the microbiological quality of meals (n = 620), work surfaces (n = 621) and the operators' hands (n = 319) in a school-deferred catering system. A general positive trend regarding the microbial contamination of food samples and surfaces was observed. Salmonella spp. and Listeria monocytogenes were never detected in prepared foods; moreover, the total mesophilic aerobes and the sulfite-reducing clostridia were always below the reference limit. The occurrence of Bacillus cereus in raw and cooked vegetables highlighted the need for corrective action and suggested that continuous monitoring of this toxin-forming microorganism was necessary. A critical evaluation of the data obtained from the microbiological analyses allowed us to obtain an overview of improvements and emerging critical issues.