Survival and Growth of Yersinia enterocolitica in Egg Washwater

Two serotypes of Yersinia enterocolitica (0:3 and 0:8) were added to a 1% (w/v) whole egg suspension and their survival was followed during exposure to conditions which reflected those used during commercial egg washing. Trials were conducted over a range of pH (7,9.5,10 and 10.5) at 38 and 42°C. The potential for Yersinia growth during transport of samples from grading stations to the laboratory at a number of storage temperatures (6,10,12 and 15°C) was also examined. Y. entercolitica strain 125 (serotype 0:3) was able to grow in synthetic egg washwater at pH 10 and 38°C (conditions frequently found at egg grading stations). Both Yersinia strains were able to grow at refrigerator temperatures when the pH was ⩽10. Recommendations concerning the conditions of egg washing were made in view of the potential for Yersinia growth in washwater during the period of its transportation to the laboratory for analysis and in view of Yersinia survival in the recycled washwater.