There are actually far more people getting sick by drinking raw, unpasteurized milk than the case counts reported in well-documented outbreaks, a study from Minnesota reveals.
For instance, there is a decade in which 21 Minnesotans fell ill in confirmed outbreaks. But actually, in the same decade an additional 530 possible individual cases were logged in state records, and there may have been 20,000 more unreported cases, says a study published Wednesday inEmerging Infectious Diseases, a publication of the federal Centers for Disease Control and Prevention.
The study also debunked one old myth according to which farm children are largely immune from such illnesses. As a matter of fact, the study showed, many of the cases involved children who drank milk produced on farms where they lived or had relatives.
While raw milk is increasingly popular with some consumers interested in natural, unprocessed foods, "it's important for people to know and understand these risks before they use raw milk or give it to children," says lead author Trisha Robinson, an epidemiologist with the Minnesota Department of Health. "Pasteurization is around for a reason."
Pasteurization involves heating milk to kill microbes that might cause disease. Most milk sold in the United States is pasteurized. But some advocates say raw milk tastes better and has more nutrients and health benefits, and 30 states allow it to be sold in some form, often straight from farms.
Public health officials have long warned about the health risks and dismissed anecdotal reports of health benefits as unscientific. A previous CDC study found raw milk was 150 times more likely than pasteurized milk to cause illness outbreaks. Most of the illnesses involve short-lived bouts of diarrhea, but they sometimes involve strains of E.coli bacteria capable of causing kidney failure and death. In one recentoutbreak in Tennessee, nine children got sick, five were hospitalized and three developed severe kidney problems, according to state health officials.
In Minnesota, 21 people were sickened in five multi-person outbreaks linked to raw milk between 2001 and 2010, the new report says.
But researchers found 530 additional cases in which people infected with various bacteria or parasites often linked with raw milk told health officials they had consumed raw milk in the week or two before.
Sally Fallon Morell, president of the Weston A. Price Foundation, a raw milk advocacy group, dismisses the new report. "Just because a raw milk drinker gets an infection, does not mean it comes from raw milk," she says.
Confirming the source of any single case is more difficult than confirming the source of a cluster, Robinson concedes. The report says it's possible some illnesses were linked to other sources, including direct contact with cattle on farms. But it also says it is possible that raw milk drinkers were less likely than other people to agree to health department interviews, meaning they were undercounted.
Researchers also consider reported cases "just the tip of the iceberg," Robinson says, because they only include people who went to doctors and had lab tests. Previous research on the ratio of reported to unreported cases suggests the 530 cases represented 20,000 actual cases. If that's true, she says, 17% of Minnesota's estimated 118,883 raw milk drinkers could have been affected.
Morell calls such extrapolation "just fiction." She says she expects "many passionate parents" who believe in the benefits of raw milk to ignore the study.
Nearly 60% of the reported illnesses in Minnesota occurred in children and teens and 25% occurred in children 5 years old or younger, the report says. Among those young children, 76% drank milk from their own farms or a relative's farm.
Confirmed multicase outbreaks find a similar "disproportionate number of children," says Michele Jay-Russell, a researcher with the Western Center for Food Safety at the University of California-Davis. While raw milk might not have caused all the individual cases in Minnesota, the pattern should give parents pause, she says.
"I'm not someone who supports banning raw milk," she says. "But I would not recommend raw milk for children, especially young children." Jay-Russell is a contributor to a website for consumers called Real Raw Milk Facts. The site is sponsored in part by lawyers for families harmed by food poisoning.
