Microbiological criteria in public catering: sampling and auditing experiences in canteens and cafeterias in Piedmont

In the period 2006-2011 six public catering establishments (3 canteens and 3 cafeterias) were monitored, trough audit and sampling, in order to verify the application of good manufacturing and hygiene practices during food production, handling and serving. The compliance to microbiological food safety criteria (Listeria monocytogenes and Salmonella spp.) and process hygiene criteria were investigated using ISO standards for microbiological analyses. A total of 612 samples were collected: 192 food samples and 288 environmental swab samples from canteens; 33 food samples and 99 swab samples from cafeterias. Regarding food safety, two samples were in disagreement with criteria fixed in EU Regulation as Listeria monocytogenes was isolated from a turkey breast in a canteen and from a sandwich in a cafeteria. Regarding process hygiene criteria, as no microbiological limits are legally defined for catering services, for this study limits were fixed according to the quality standards of tender, scientific literature and laboratory experience. 23.4% foodstuffs and 8.7% swabs resulted non-compliant in canteens; 48.5% foodstuffs and 6.1% swabs resulted non-compliant in cafeterias. The count of coagulase-positive staphylococci (CPS) was higher of the fixed limits in raw turkey meat and in cooked spinach: the presence among CPS of S. aureus was confirmed, strains were not able to produce enterotoxins. The most common non-compliance in hygiene criteria was represented by aerobic colony count (60.7% of total non-compliance in canteens and 75.0% in cafeterias) and coliform bacteria (20.3% in canteens and 25.0% in cafeterias). Nine raw foods or raw readyto- eat food samples were non-compliant for both coliform bacteria and aerobic count; one sample (raw turkey meat) was non-compliant for CPS and aerobic count but resulted to be compliant after cooking. Auditing and sampling are the most effective tools to improve food quality standard and to enhance food business operators’ awareness of hygiene procedures.