Saturday, November 6, 2010

Rare E. coli Strain Behind Raw Milk Cheese Outbreak

Outbreak strain "...never been seen before in the PulseNet database."

A raw milk cheese manufactured by Bravo Farms (Traver, CA) is suspected to be the source of a five-state outbreak of E. coli O157:H7. The Dutch Style Gouda Cheese was among those offered for sampling and for sale in Costco stores in Arizona, California (San Diego), Colorado, Nevada and New Mexico – the same five states that have reported the illnesses. Twenty-five infections have been reported so far.

According to CDC, this particular outbreak strain is a rare one. It has never before been reported to the federal PulseNet database – the national subtyping network made up of state and local public health laboratories and federal food regulatory laboratories that performs molecular surveillance of foodborne infections.

What do we know about this outbreak?
  • 25 patients have been reported to be infected with this rare strain of E. coli O157:H7.
  • At least 9 people have been hospitalized – one of them with suspected hemolytic uremic syndrome.
  • The victims live in Arizona, California, Colorado, New Mexico and Nevada.
  • The youngest victim is 2 years old, and the oldest is 81 years old.
  • The earliest onset date in this outbreak was October 16th.
  • There is a good likelihood that more cases will be reported, since the suspect food was on the market until at least November 1st.
  • E. coli O157:H7 has been found in an opened package of Bravo Farms Dutch Style Gouda Cheese obtained from one of the 25 outbreak victims. The package was purchased at Costco.

What do we know about the outbreak victims?
Three of the affected states have released additional information that is not contained in the CDC report.
  • The lone California victim is a six-year old girl who lives in San Diego County. San Diego was the only Costco location in the state that carried the implicated cheese.
  • New Mexico's three victims include a 41-year-old man and 7-year-old girl from Bernalillo County and a 4-year-old boy from Valencia County.
  • Colorado has received a total of eight illness reports from three counties: Douglas (4), Arapahoe (3) and Boulder (1). All eight were Costco shoppers, most of whom sampled cheese during a “Cheese Road Show” at Costco Oct. 14-17.

What is the status of the outbreak investigation?
Based on the results of patient interviews and on the finding of the outbreak strain in an opened sample of cheese that had been purchased at Costco by one of the 25 victims, attention has been focused on Bravo Farms Dutch Style Gouda Cheese. This raw milk cheese is a product of Bravo Farms, a cheese factory that is located in Traver, California. The company manufactures eight varieties of aged raw milk cheeses, all of which can be purchased on-line via the Bravo Farms web site. The company is cooperating with FDA and state investigators, but has not yet issued a formal public recall notice.

No doubt, FDA and California investigators already are on-site at Bravo Farms, carrying out an intensive investigation and sampling. Testing for E. coli O157:H7 will not be limited to the specific variety of cheese that is thought to be the source of this outbreak; it will extend to all eight varieties, and will include extensive environmental testing, too. The herd of dairy cattle that supplies milk to the cheese factory most likely also will be examined for the outbreak strain. The goal is to determine both the source and the extent of the problem.

What should consumers do?
Based on the information collected so far, the source of the outbreak appears to be limited to cheese that was sold or available for taste-testing between October 5th and November 1st at Costco locations in the five states from which cases have been reported. Costco has removed the product from its stores and is contacting customers who purchased the product, in order to alert them to the situation and ask them to return the product to their Costco location for refund.

Consumers who purchased Dutch Style Gouda Cheese directly from Bravo Farms during the October 5th through November 1st time period should contact the company for more information. While Bravo Farms has not issued a formal public recall notice, the company is cooperating with Costco's recall activities and says that it has contacted by telephone those who purchased the product.

Anyone who has consumed any one of the eight varieties of Bravo Farms raw milk cheese that was purchased on or after October 5th – especially the Dutch Style Gouda – and who begins to experience symptoms of gastroenteritis (stomach ache, diarrhea, nausea, etc.) may be infected with E. coli O157:H7, and should consult a doctor immediately.

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  1. Do we know any more details about about how Bravo Farms was preliminarily implicated? For example, were there other cheeses being sampled at the "Cheese Road Show," that tested negative, or was the Gouda singled out for testing because it is a raw milk cheese?

    Also, we would like to see testing of an unopened gouda wheel directly from the production site--otherwise, it may be a contaminated cutting board.

  2. @Anonymous.- Bravo Farms Gouda was one of several cheeses offered at the "Cheese Road Show" and also was sold by Costco. Some of the outbreak victims purchased the Bravo Farms Dutch Style Gouda (as opposed to simply tasting one or more cheeses at the show). The "preliminary" implication is based on an analysis of the foods that outbreak victims reported having eaten during the several days prior to becoming ill.The Gouda was not specifically singled out simply because it is a raw milk cheese. That's not how CDC epidemiologists conduct their investigations.

    I agree that the ultimate confirmation is the detection of the outbreak strain in an unopened gouda wheel directly from the production site. FDA and the state labs are working on this as I type.



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