A bulletin for the Australian Food Industry December 1996
Contents: Enterohaemorrhagic E. coli outbreak in Japan | Cross-contamination and EHEC | Repercussions from food poisoning incidents | Statistical methods and food safety | National food hygiene standard | Botulism linked to cheese
Enterohaemorrhagic E. coli outbreak in Japan
Although the situation is not yet entirely clear, WHO reported in September that the major outbreak of enterohaemorrhagic E. coli in Japan in the middle of this year involved more than 9500 cases with at least eleven deaths. Other reports place the death toll higher.Most of the reported cases were amongst school children aged from 6 to 12 years in Sakai city in the region of Osaka. However cases have occurred in forty Prefectures and several food products have been implicated. Approximately 100 patients developed haemolytic uraemic syndrome (HUS) and E. coli O157 was detected in 287 out of 542 patient stool samples. School lunches which were prepared in individual schools from foods delivered by a central supplier remain the suspected cause of the Sakai outbreak but the responsible food item has not been confirmed. Various foods, including beef, eel, watercress and radish sprouts have come under suspicion but except for one unrelated case in which a nine year old boy became infected after eating raw cow's liver, authorities have been unable to pinpoint the origin of the infections. Analysis of DNA patterns of isolates of E. coli O157 from different incidents suggests that more than one food type has been the source of infection.
Anecdotal reports appearing in the Japanese press indicate that food suppliers for school lunches in Sakai, which was the focus of by far the largest outbreak of illness, are distributed to schools by seven unrefrigerated trucks. Truck distribution began as early as 5:30 a.m. and foods may have remained unrefrigerated for some hours before preparation and serving of lunches. It is also common practice in Japanese schools for children to be asked to prepare meals for other children. This would possibly increase the risk of cross-contamination from one food to another.
Although E. coli O157 has been found in only one sample of imported beef examined by Japanese health officials, imported beef sales to Japan, including those from Australia, have fallen dramatically. A sample of raw beef small intestine imported from the United States was positive for E. coli O157 but the shipment involved was never released to the Japanese market place. Japanese officials have found E. coli O157 in a number of domestic beef samples including at least one from a supplier to the Sakai district. Authorities in Japan have ordered a major tightening of hygiene standards at slaughterhouses and meat processing works.
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