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Marler Blog Providing Commentary on Food Poisoning Outbreaks & Litigation

Minnesota Department of Health Responds to Hartmann Dairy on the Raw Milk E. coli O157:H7 Outbreak

Yesterday after giving a speech to NEHA on the dangers of the industrialized beef supply, I received the following email statement from the Hartmann Dairy which is at the center of an E. coli O157:H7 outbreak in Minnesota that has sickened at least five. Here is the relevant part of the email:

Not a single test of raw milk was found to contain any strain of e.coli.

At paragraph 9, the State wrote in the Petition that of the 103 samples tested, 9 samples tested positive for e.coli, a bacteria found in the lower intestines of virtually all mammals. Of the 9 samples, none was from any milk cow; 4 calves manure (not milked), manure from a cow pen (beef cows, not dairy, not milked), manure from a pasture for dry cows (not milked), manure from a steer yard (steers are not milked), manure from 2 heifers (not milked), and manure from one sheep (not milked). No claim is made that any sample from a dairy cow or the dairy barn contained any e.coli.

Two samples of cheese, one cheddar and one herb and spice Gouda, made from raw milk were found to contain a strain of e.coli that the state could not identify as e.coli 0157:H7. A third positive test for an unidentified strain of e.coli was taken from a bucket of clean-up rinse water. As everyone knows, cheese is intentionally cultured with bacteria to create the product and until a specific strain is identified there is no evidence of contamination.

As of today, there is no evidence of any harmful bacteria in any raw milk, cheese, meat or other product sampled from the Hartmann farm. The State has engaged in a serious regulatory and potentially criminal action in a grossly negligent manner with total disregard for the defamatory content of their media campaign.

Minnesota Department of Health responded. The response, in part, is below:

What evidence do you have that raw milk from the Hartmann farm caused the illnesses?

This investigation began like many other foodborne investigations: Someone becomes ill, sees their physician and the physician sends a stool specimen to a clinical laboratory. If that laboratory finds, or “isolates”, one of a number of illness-causing bacteria (eg., Salmonella, E. coli O157:H7), they send that bacterial isolate to the MDH Public Health Laboratory (PHL) for further testing. Each bacterial isolate is DNA fingerprinted by a technique called pulsed-field gel electrophoresis (PFGE).

During May 2010, E. coli O157:H7 isolates from 5 patients sent by separate clinical laboratories to the MDH PHL were found to all have the same DNA fingerprint by PFGE testing.

This particular DNA fingerprint type (which also can be called a “strain”) of E. coli O157:H7 had never been seen before in Minnesota. The fact that multiple patients all were infected with this new strain in such a tight timeframe indicates that there was a common source for the illnesses. In other words, the patients must have acquired their infection from the same source.

In any foodborne illness investigation, MDH epidemiologists interview patients about an extensive array of possible exposures. These interviewers use a standard questionnaire and interview technique. This includes asking questions about what the ill people ate, including meat, produce and other food items. It also includes questions about recreational water and drinking water, contact with animals, daycare attendance, and more.

In this outbreak, the ill people came from communities across Minnesota, and the only exposure the cases had in common was consumption of raw dairy products from the Hartmann farm. This connection, and the fact that the same strain of E. coli O157:H7 found in the ill people was found in several animals and from several environmental samples on the Hartmann farm, clearly indicates that the farm was the source of the E. coli O157:H7 that made the people ill.

What is the significance of finding E. coli O157 in the environmental samples from the farm?

The strain found on the farm matches the strain found in the cases of illness. Again, this is a strain that has never been seen before in Minnesota.

This tells us that the bacteria that sickened the people was on the Hartmann farm and since several of the people that became ill never visited the farm, their only potential source would have been food products from the farm.

Did you find the outbreak strain in dairy product from the cases’ homes or from the farm?

The outbreak strain of E. coli O157:H7 has not been found in product yet. However, product samples that were collected from the farm were obtained one week to several weeks after production of products that made people sick. Other strains of Shiga toxin-producing E. coli were found, indicating an ongoing problem with contamination.

The fact that the outbreak strain was not found in samples of product taken from the farm or homes does not mean it wasn’t in the product that sickened the individuals. In many cases, only particular batches of product may have been contaminated. The product from the contaminated batches may not be available for testing because it has already been consumed. Even if the contaminated batches are available for testing, the contamination may not be uniformly distributed throughout the product. It can be difficult to find the “needle in the haystack” when only small amounts of product are able to be used for a laboratory test. The fact that some pathogen was not found in a sample taken today does not mean it wasn’t there yesterday or a week ago, or won’t be there tomorrow. Also, since raw milk contains many types of bacteria it is a difficult process to isolate individual bacteria growths and find the disease-causing strains.

The outbreak strain of E. coli O157:H7 was found in the manure of some individual calves, sheep, and cattle pens. Of note, the calves were likely drinking the same milk as that consumed by the cases.

Standard public health practice does not require finding the illness strain of pathogen in either environmental or product samples in order to determine the source of an outbreak and before intervention to prevent further illness should be initiated. In fact, it is quite rare in foodborne investigations that food product is available for testing as it is often perishable or has been completely consumed by the time the outbreak is recognized. State health and agriculture officials often act on epidemiologic evidence to remove contaminated products from the marketplace and prevent additional illnesses. Indeed, to do nothing in the face of such compelling evidence would be irresponsible – regardless of the size or nature of operation implicated.

Are there more cases being investigated?

Yes, MDH has received additional reports of illness in several consumers of Hartmann dairy products that it is investigating.

The Minnesota Department of Health Epidemiologists and the Health Department lab are considered the best in the country at investigating foodborne outbreaks.  Its response to the Hartmann Dairy is as devastating to Hartmann’s wishes as it is accurate and clear.

  • fred b

    It is not surprising that someone from Hartmann Dairy would try to bull their way out of this, but I’m glad the MDH was not cowed by their tactics. It seems that B.S. (or Steer S.) is a way of life for some; unfortunately they see fit to share it with the rest of us in ways we don’t want. Well, we won’t be penned in by such low tactics! It’s time to move on to the truth.
    Next, they’ll be blaming the ewe for the whole thing, in another attempt to ram another sheep shot down the public’s throat. But, who knows? They may chicken out!

  • Tim

    I think the Minnesota Department of Health did a great job in this response, but you did not include the entire response (http://www.health.state.mn.us/foodsafety/alert/ecoli0610.html) and there are two things mentioned later that I found annoying. First, when addressing any raw milk benefits, they took the narrowest view possible saying there was no meaningful nutritional difference. You yourself have identified studies that linked raw milk consumption to improvement in allergies, which most people who suffer from allergies would say is a benefit. Second, they said that at best, an e. coli infection could cause two weeks of bloody diarrhea. What? At best, e. coli will be fought off by your immune system and you won’t notice it. Again, generally the article is just what I want out of my Department of Health, but why did they have to put in a half truth and a lie, however venial they were? They already had it nailed. Those lines just cheapened the whole thing.