Effect of Heating, Freezing, and pH on Yersinia enterocolitica -like Organisms From Meat.

No survivors of Yersinia enterocolitica were detected in beef roasts inoculated at levels as high as 3.1-3.8 × 106 viable cells per g when the final internal temperature in the center was 60 to 62 C. At 51 C some Y. enterocolitica survived. Extensive destruction of Y. enterocolitica occurred on beef during frozen storage. Counts of surviving organisms were greater on tryptic soy agar than on bismuth sulfite agar plates. Growth of Y. enterocolitica in brain heart infusion was better at pH 7 and 8 than at 6 or 9. Little or no growth occurred at pH 5.