Raw (unpasteurized) milk has become a popular item within certain foodie circles in recent years. Some adherents go to such great lengths to acquire it that the purchasing process sounds more like a seedy drug deal than a trip to the market. Fans tout several benefits, ranging from nutritional to ethical to environmental, but even the most ardent activists always acknowledged a small risk of illness. Well, it turns out those risks were understated: A new study estimates that as many as one in six people who drink raw milk will get sick.

Due to the lack of pasteurization, raw milk is well-established as a vehicle for bacterial diseases including Salmonella, E. coli and Campylobacter, as well as parasitic infections. Researchers in Minnesota found 530 confirmed cases of infections among raw milk drinkers whose circumstances lead scientists to believe that raw milk consumption was the most likely candidate. Based on accepted rates for under or misdiagnosis, the researchers were able to extrapolate that over 20,000 Minnesotans (17 percent of the raw milk drinkers) actually became ill as a result of unpasteurized milk consumption.

“The risk for illness associated with raw milk is far greater than what was determined based on recognized outbreaks,” said study researcher Trisha Robinson, an epidemiologist at the Minnesota Department of Health, according to LiveScience.

The new finding raise (or should raise) serious concerns among lawmakers, who in some jurisdictions are facing increasing pressure to relax regulations regarding milk sales.