We’ve previously warned about the risk of bacterial contamination in raw (unpasteurized) milk. Now a report from the Center for a Livable Future at Johns Hopkins Bloomberg School of Public Health provides some solid numbers about its hazards: Though only a tiny percentage of Americans consume raw dairy products, unpasteurized milk has been associated with more than half of all milk-related foodborne illnesses, making it more than 100 times riskier than pasteurized milk.
Raw milk can be contaminated with Listeria, Salmonella, Campylobacter, and other disease-causing pathogens. Pasteurized milk, on the other hand, is heat-treated to destroy these pathogens. Foodborne illness related to raw milk typically causes nausea, vomiting, and diarrhea, but it can also lead to sepsis, kidney failure, and even death, especially in pregnant women, children, the elderly, and people with compromised immunity.
The review was done at the request of the Maryland House of Delegates, which is considering a bill that would make farm sales of raw milk legal in that state. At present, 30 states allow the sale of raw milk (usually at farms or through “cow share” programs), though interstate shipment is illegal. The Hopkins scientists concluded that from a public health perspective, consuming raw milk should be discouraged.
Other key findings:
- Despite claims that raw milk is better tolerated by people with lactose intolerance, pasteurization “does not substantially change the lactose content in milk.”
- Consumption of raw milk has been associated with a lower risk of allergies in infants and children in rural communities. But “this has not been proven to be a causal relationship,” according to the report, nor has a biological mechanism been identified. The observed relationship may be due to other factors, such as exposure at an early age to farm animals, which has also been associated with lower risk of allergies. In any case, the authors of all the studies that have found this potential benefit still recommend against drinking raw milk because of its serious risks.
- Pasteurization produces only “marginal” changes in the nutritional composition of milk. And even in cases where heat treatment does substantially reduce vitamins (such as B12 and riboflavin), milk is either not a significant source of them to begin with, or these vitamins are easily obtained from other foods. That is, eating a balanced diet more than makes up for any losses that occur during pasteurization.