Raw milk from Minnesota farm, sick people, linked by DNA testing

Epidemiology is an imperfect science; but it’s better than astrology, especially when people are seriously barfing.

Producers of food, big and small, have all employed various lines over the years to say, the evidence doesn’t really prove a specific food made a bunch of people barf or kill them. Governments have done the same thing in protecting various food-producing industries. The widespread standard of proof in the form of DNA fingerprinting was just being contemplated when I graduated with a molecular biology and genetics degree in 1985, and was dependent on a couple of other technologies, especially polymerase chain reaction of PCR amplification of small amounts of DNA.

But occasionally, the food detectives catch a break, and can definitively link a food product with sick people.

This has happened in Minnesota.

Laboratory testing conducted by the Minnesota Department of Agriculture (MDA) and the Minnesota Department of Health (MDH) this week provided additional evidence that the Hartmann dairy farm, of rural Gibbon, was the source of a strain of E. coli O157:H7 bacteria that sickened at least five Minnesotans after they consumed raw, unpasteurized milk or other dairy products from the farm. MDH reported four cases of illness last week, and a fifth case has subsequently been confirmed in a young child who was not hospitalized.

MDH first discovered the outbreak through reports of E. coli O157:H7 illness from health care providers. The department conducted an investigation into the illnesses, which were scattered across the state, and found that the only thing the ill people had in common was consumption of dairy products from the Hartmann farm. This strong epidemiological link is now reinforced by the laboratory confirmation that the specific strain of E. coli O157:H7 found in the ill patients has also been found in multiple animals and at multiple sites on the Hartmann farm. This strain of E. coli has not previously been found in Minnesota. Furthermore, laboratory tests confirmed that cheese samples collected last week from the farm contained another form of Shiga toxin-producing E. coli, demonstrating that an ongoing pathway of contamination existed on the farm. …

In addition to the cases linked to the Hartmann farm, MDH is investigating several other illnesses with a connection to products from the farm. MDA has embargoed dairy products on the Hartmann farm, prohibiting movement or release of the products off the farm.

An updated table of raw-milk related outbreaks is available at ?http://bites.ksu.edu/rawmilk