Ein Beitrag zum Vorkommen von Yersinia enterocolitica in Hackfleisch und Fleischerzeugnissen vom Schwein im Hinblick auf die eingesetzten Kultur- und Isolierungsverfahren

摘要

Occurence of pathogenic Y. enterocolitica 4/O:3 in pork in southern GermanyThe prevalence of pathogenic Yersinia enterocolitica in pork products in Southern Germany was studied because no data is available of distribution of this pathogen at retail level in Germany. A total of 300 meat products containing pork from different plants were collected between May and August year 2000. These samples consist of 215 raw and 85 heat-treated products. The samples were studied with different culture methods: direct plating, overnight enrichment in TSB combined with alkali treatment, selective enrichment in MRB and ITC, and cold enrichment in TSB followed by alkali treatment. Y. enterocolitica was isolated from selective CIN agar plates. Urea-positive colonies were identified using API 20E. Y. enterocolitica isolates were bio- and serotyped, and the pathogenicity was confirmed with Congo red binding and Calcium dependence on CRMOX agar plates. Pathogenic Y. enterocolitica was recovered from raw meat products but not from heat-treated products. The isolation rate of Y. enterocolitica 4/O:3 in minced meat was 9.0%. This type was also found two times (7.4%) from raw pork. All pathogenic Y. enterocolitica isolates were belonging to bioserotype 4/O:3. Selective enrichment in ITC was shown to be the most productive method for raw meat products. No pathogenic Y. enterocolitica isolates could be recovered after non- selective enrichment even when combined with alkali treatment. These results show that raw pork can be one source of Y. enterocolitica 4/O:3 infections among humans in Southern Germany. This study also demonstrates that no pathogenic Y. enterocolitica can be found without selective enrichment.