Prevalence of pathogenic Yersinia enterocolitica in food samples at retail level in Finland

Prevalence of pathogenic Yersinia enterocolitica was studied in pork, fish, chicken and lettuce at retail level with the PCR and culture methods. A high prevalence of pathogenic Y. enterocolitica was detected in pig tongues, hearts and kidneys with both methods. Three out of 101 lettuce samples were positive with only the PCR method. All fish and chicken samples were negative with both methods. Some nonpathogenic Y. enterocolitica isolates were recovered from fish, chicken and lettuce samples. The PCR method was clearly the more sensitive method, even though false-negative results were also obtained. Pathogenic, yadA-positive isolates were recovered after selective enrichment. All of these isolates belonged to bioserotype 4:03, but all isolates of this type were not yadA-positive. These results show that raw pork is an important source of pathogenic Y. enterocolitica at retail level in Finland. La prevalence, en Finlande,au niveau des points de vente au detail, de Yersinia enterocolitica dans des echantillons d'aliments a ete etudiee par PCR et methode microbiologique. Les produits a base de porc sont souvent contamines, contrairement au poisson, au poulet et a la laitue.Les isolats appartiennent au serotype 4:O3.