AN OUTBREAK OF YERSINIA ENTEROCOLITICA INFECTIONS CAUSED BY CONTAMINATED TOFU (SOYBEAN CURD)

Abstract

The authors investigated 50 Yerslnle enterocolltlca Infections during an out break of illness due to contaminated tofu (soybean curd) in Washington State between December 15, 1981 and February 22, 1982. The most common clinical syndrome (36 patients) was gastrointestinal infection for which two patients underwent appendectomies and one a partial colectomy. Of the remaining 14 patients, six had extraintestinal infections, two had fever alone, and six were asymptomatic. The patients with enteric infections were younger (median age three years) than those with extraintestinal infections (median age 28 years). in a case-control study of enteritis patients, illness was associated with ingestion of one brand of tofu (p < 0.01). Ninety-two per cent of patients with gastrointes tinal infections and 33% with extraintestinal infections recalled having eaten the implicated product Y. enterocolltlca serotype 0:8, the most common serotype isolated from patients, was also isolated from tofu and the plant's untreated spring water. There was little clinical or laboratory evidence of secondary spread to family members who did not eat tofu. The outbreak demonstrates the trans mission of Y. enterocolltlca from nature to man and the potential of “natural” foods as vehicles for environmental pathogens.