Local authorities in Missoula, MT, are warning people to not consume raw milk sold at a farmers market because it came from a herd wher cows tested positive for Coxiella burnetii, which is the bacteria that causes Q fever.

The unpasteurized, raw milk was sold at a farmers market in Missoula County, according to the Missoula City-County Health Department. The department did not specify what farmers market is involved.

“We don’t know if the cow was shedding the bacteria at the time it was milked, or if that cow’s milk was sold at the farmers market,” said Environmental Health Director Shannon Therriault. “So we can’t say for sure whether anyone was exposed. However, what we do know is that unpasteurized milk can contain harmful bacteria that can make you and your loved ones sick.”

The health department warned that unpasteurized milk products have been linked to outbreaks of E. coli, campylobacter, salmonella, brucella, listeria and cryptosporidium in addition to Q fever. In the case of Q fever, symptoms can take two or three weeks to become apparent following exposure. According to the U.S. Centers for Disease Control and Prevention, symptoms of Q fever include fever, chills, fatigue, headache, muscle aches, nausea, vomiting, diarrhea, chest pain, stomach pain, weight loss and a non-productive cough.

“While drinking ‘raw’ milk has become more widespread in recent years, we want people to know that it can easily be contaminated with harmful bacteria, even when the milking operation is well-run,” Therriault said. 

In the 1980s, Missoula experienced a large salmonella outbreak caused by unpasteurized milk from a local dairy. More than 100 cases were linked to the outbreak, and half of those cases were children 14 and younger, according to the health department. 

The strain of salmonella was multi-drug resistant, and 15 percent of those who got sick were hospitalized. An inspection of the dairy revealed no sanitation laws or practices on the books at that time were broken, but people still got sick.

After that outbreak, Montana passed a law that all milk sold to consumers had to be pasteurized. The CDC reports that when milk pasteurization requirements began in the early 1990s, deaths and diarrheal illnesses in young children declined dramatically.

In 2021, the legislature reversed course, and unpasteurized milk sales are now allowed in Montana under certain, limited conditions. Unpasteurized milk can be sold at a farm, farmers markets and other traditional community events, as long as the herd is five lactating cows or fewer, and the seller informs the end consumer that the product is not licensed, certified, packaged, labeled or inspected under any official regulations.