A Multistate Outbreak of Infections Caused by Yersinia enterocolitica Transmitted by Pasteurized Milk

In June and July 1982, a large interstate outbreak of Yersinia enterocolitica infections caused by an unusual serotype occurred in Tennessee, Arkansas, and Mississippi. Eighty-six percent of cases had enteritis characterized by fever, abdominal pain, and diarrhea. In three separate case-control studies, drinking milk pasteurized by plant A was statistically associated with illness. In a survey of randomly chosen households, 8.3% of persons who recalled having drunk milk from plant A during the suspect period experienced a yersiniosislike illness. Inspection of the plant and cultures of the available raw and pasteurized milk did not reveal the source or mechanism of contamination or a breach in normal pasteurizing technique. Although outbreaks of enteric disease caused by pasteurized milk are rare in the United States, the ability of Y enterocolitica to grow in milk at refrigeration temperatures makes pasteurized milk a possible vehicle for virulent Y enterocolitica. The extent to which milk is responsible for sporadic cases of yersiniosis is unknown.