Last month, state agencies in Wisconsin warned the public not to drink raw milk after 13 people in the southeastern part of the state had become ill shortly after consuming the unpasteurized product.  Individuals who had consumed raw milk, which is illegal to sell or distribute in Wisconsin, tested positive for Campylobacter jejuni.  

Campylobacter jejuni bacterial infection causes nausea, diarrhea, abdominal cramping, fever and vomiting.  It sometimes leads to severe complications.

Wisconsin said then it was investigating the source, but it was too early to talk about punishment. Yesterday, the Wisconsin Department of Agriculture, Trade, and Consumer Protection announced that a joint epidemiologic investigation conducted with the Wisconsin Department of Health Services has found 35 confirmed cases of Campylobacter jejuni infection, including 21 patients under age 18.

One person was hospitalized.  All patients had consumed unpasteurized milk.

Wisconsin issued this update on the outbreak:

Thirty of the patients identified Zinniker Family Farm, Elkhorn, as the source of the raw milk. The farm sells raw milk through a “cow-share” program. Twenty-seven of the confirmed cases were in Walworth and Waukesha counties; the rest were in Racine and Kenosha counties. Additional testing showed that the Campylobacter jejuni isolated from 25 of the patients — all linked to Zinniker Family Farm — had the same DNA fingerprint.

Manure samples obtained directly from milking cows on that farm also tested positive for Campylobacter jejuni with the same DNA fingerprint. Manure on the cows’ udders or in the milking barn environment can contaminate milk. Pasteurization kills Campylobacter jejuni and other disease-causing bacteria in milk.

The Zinniker Family Farm, established in 1943, has 30 Holstein dairy cows, a breeding bull, and about 20 head of young stock of varying ages, and 220-250 chickens on 165 acres.  On a website for the Fields Neighborhood, the farm advertises that: “Since the mid-1980’s the farm has been supplying consumers with fresh raw milk through a Cow Ownership Program.”

Steve Ingham, who heads Wisconsin’s Food Safety Division, said, “Because Zinniker Family Farm sells milk to a defined customer list, there is little risk to the general public in this case.  However, the outbreak should discourage consumers from joining ‘cow-share,’ membership, or other similar arrangements to buy raw milk, and should discourage dairy producers from adopting such an arrangement for their farms.

“Some farmers believe that such arrangements exempt them from the law. They are mistaken. The law says that owners may consume raw milk from their farms, but those owners have to be true owners with a real financial stake in the farm. And the law clearly says that unpasteurized milk can be sold only to a licensed dairy plant or to other licensed businesses that sell to dairy plants,” he said.

Ingham did not say if the farm owners will face any charges.

Past outbreaks in Wisconsin that have been tied to raw milk include:

In December 2001, at least 30 laboratory-confirmed cases of Campylobacter jejuni were identified in northwestern Wisconsin, all tied to a cow-share program.

In June 2006, 19 laboratory-confirmed and 39 probable cases of Campylobacter jejuni infection were traced to cheese curds made from unpasteurized milk in an unlicensed facility by an unlicensed cheese maker in Ashland.  The cases occurred in many Wisconsin counties and six other states.

Nationwide, the Centers for Disease Control and Prevention (CDC) reports that 45 outbreaks tied to unpasteurized milk or cheese consumption occurred from 1998 to 2005. These outbreaks occurred in 22 states, two were multi-state outbreaks, and they resulted in 1,000 illnesses, 104 hospitalizations and two deaths.

In an article published in the Wisconsin Medical Journal in August 2000, the Wisconsin Division of Public Health reported that from 1992 to 1999, consumption of raw milk and raw milk products was one of the top three risks for E. coli O157:H7 infection in Wisconsin.  E. coli O157:H7 infections can be fatal.