When people get sick from drinking raw milk, it gets a lot of attention in the media. But a new study suggests those documented cases may be just the tip of the iceberg.
Minnesota Department of Health statistics show that over a ten-year period, the number of people in the state who may have been sickened by raw milk was 25 times higher than the number of cases traced to well-publicized outbreaks.
The study's authors hope their findings will be used to educate consumers about the risks of drinking raw milk.
"You know raw milk is an incredibly risky product," said epidemiologist Trisha Robinson, lead author of the study. "Basically, with that many people getting sick, it's something for people to think long and hard about before they consume it."
The Health Department study reviewed disease data from 2001 to 2010. During that time there were more than 20,000 cases of laboratory-confirmed intestinal illnesses that were traced to several reportable diseases. The pathogens include salmonella, campylobacter, cryptosporidium and two toxin-producing strains of E. coli.
Researchers excluded about a fourth of the cases due to insufficient data collection and other reasons. Of the remaining cases, Robinson said 530 individuals reported that they had consumed raw milk during their disease exposure period. While 530 may not sound like a huge number, "it is actually 3.7 percent of individuals, so it is actually a pretty sizable number," said Robinson.
About half of the intestinal illnesses occurred in children 17 and younger. The one death reported during that time period was an 11-month-old infant who developed kidney failure after contracting an E. coli infection.
"They're all individuals who reported raw milk consumption," said Robinson. "Can we say with 100 percent certainty that their illness came from raw milk? No, we cannot say that. We can say that they reported raw milk consumption. It is a very likely source of their infection."
The study findings don't sit well with Leo Cashman, president of the Minnesota Natural Health Legal Reform Project and an advocate for raw milk consumption.
"They're just concluding that these symptoms are associated with this disease, so what you've had is very, very sloppy, loose categorization of illnesses as fitting into a disease pattern," said Cashman.
Cashman says he would need to see confirmed cases of illness traced to raw milk before he would change his opinion of raw milk. He says it's a natural product with many health benefits, especially for children. And he says it doesn't make sense to him that it would cause serious illness.
"Did any of these children who were ill, or the one who died, did they have other complications? Were there other reasons why the child may have died?"
Cashman worries that the Health Department study could lead to more restrictions on selling raw milk in Minnesota, at a time when the raw milk industry wants to loosen regulations that prevent farmers from transporting or selling their product off the farm.
The Health Department is not taking a position on Minnesota's raw milk law, according to study author Trisha Robinson. But she said the agency has an obligation to inform the public about the risks of drinking raw milk.
Robinson said the study, which is being published in the Centers for Disease Control and Prevention publication, Emerging Infectious Diseases, is the first of its kind and potentially of interest to many other states where raw milk is sold.
"We're hoping that it will get out to all of our public health colleagues in other states, clinicians and hopefully the word will get out there to the general public that are either consuming raw milk or considering consuming raw milk," said Robinson.