Prevalence of pathogenic Yersinia enterocolitica in food samples at retaillevel 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 hi gh 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 negat ive with both methods. Some nonpathogenic Y. enterocolitica isolates were r ecovered from fish, chicken and lettuce samples. The PCR method was clearly the more sensitive method, even though false-negative results were also ob tained. Pathogenic, yadA-positive isolates were recovered after selective e nrichment. All of these isolates belonged to bioserotype 4.03, but all isol ates 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 F inland.