Retrospective study on the hygienic quality of fresh ricotta cheeses produced in Sicily, Italy.

The present work was carried out to investigate the microbiological profile of Sicilian ewes' ricotta cheeses during fifteen years of investigations (2002-2016). The samples were collected between those conferred to the Istituto Zooprofilattico Sperimentale della Sicilia (IZSSi) , Palermo (Italy), by the competent authority during official control, by food business operator in HACCP systems and in research projects. and coagulasepositive staphylococci (CPS) were found only in some samples. was detected in c.a. 16% of samples but the level of contaminations did not reach the threshold that leads to significant toxin production. Pathogenic bacteria such as , spp. and spp. were never detected. Furthermore, a total of 47 of lactic acid bacteria (LAB) strains were identified at species level by sequencing the 16S rRNA gene, resulting in the identification of 10 species belonging to four genera , , and , commonly employed as starter and non starter cultures in different traditional cheese. Results of this study highlighted an improvement of the hygienic conditions of the Sicilian ewes' ricotta cheeses during the last ten years of investigation. This observation was confirmed from reduction of undesired microorganisms such as , and CPS, used to define the process hygiene criteria. However, in order to improve the final quality of this product are needed further strategy such as the dairy makers training, with the aim to apply a good hygienic practices during the production.