E.Coli O157:H7 outbreak associated with fresh cheese curds

American Medical Association

A recent report in the October 13 issue of the Morbidity and Mortality Weekly Report (MMWR) indicates that a June 1998 outbreak was due to fresh cheese curds in a dairy plant.

On June 15, 1998, the Division of Public Health, Wisconsin Department of Health and Family Services, was notified of eight laboratory-confirmed and four suspected Eschericia coli O157:57 infections among west-central Wisconsin residents who became ill during June 8-12.

As a result of the outbreak investigation, the eating of fresh cheese curds produced from one dairy plant was implicated.

The investigation further showed that the dairy plant produced unpasteurized (raw milk) cheddar cheese daisies. Certain raw milk cheese products can produced and legally sold as long as the cheese is held at <35 F (.1.7 C) for at least 60 days before it is sold. However, cheese curds are sold fresh (held <60 days); therefore curds must be made with pasteurized milk. It turns out that at least one 1,500-lbs vat of raw milk cheddar cheese was used inadvertently to make fresh curds, which were incorrectly labeled "pasteurized" cheddar cheese curds, and distributed and sold in six Wisconsin counties.

The accompanying editorial (in Morbidity and Mortality Weekly) emphasizes that raw milk consumption has been associated with campylobacteriosis, salmonellosis, E. coli O157:57, yersiniosis, listeriosis, tuberculosis, brucellosis, cryptosporidiosis, and staphylococcal enteroxin poisoning. Additionally, the editorial says that this outbreak investigation illustrates the hazards of using raw milk to produce commercial products that may lead to mislabeling or contaminating pasteurized product by equipment or ingredients. This practice can result in pasteurized products contaminated by equipment or ingredients and in product mislabeling.