In these last years it was observed an increased frequency of human infections by Y. enterocolitica supported mostly in Europe by serotype 0:3 and 0:9, and by serotype 0:8 in U.S.A. As far as it is concerned the transmission form to man, in addition to the possible infection between men, the one from animal to man and the one consequent on water use, most important suspicions are about foods derived from infected animals or however contaminated by man (fresh or preserved or processed meat, milk and its products; the produce of sea). Y. enterocolitica was isolated from all the animals for slaughter (especially from the swine's pharynx and excrement, where pathogenic serotypes for man were isolated), this ascertainment has led the Authors to research the microorganism in foods of animal kind. It is a facultative anaerobe and this characteristic allows it to survive and multiply also in packed products kept in the refrigerator. For this reason the A.A. carry out a research of Y. enterocolitica on 484 samples of fresh meats and sausages as follows: beef (150 samples), superficial scratching of ox's skeleton (150 samples), minced meat (20 samples), sausages (164 samples). Sausages and beef were bought in some butcher's shops, the other samples were drawn from slaughter-houses of Messina province. The results have pointed out that none of the analysed samples is found contaminated by these microorganisms.