Got milk? Understanding the farm milk effect in allergy and asthma prevention.

Cow’s milk is a major component of most of our diets, but concerns about its ingestion have been in and out of public health dialogues for decades. Raw milk has long been associated with numerous foodborne illnesses and outbreaks due to enteric and opportunistic bacteria such as Brucella, Salmonella, Listeria monocytogenes, Yersinia, Campylobactor species, Staphylococcus aureus, and Escherichia coli species.1,2 Mycobacterium bovis infection was transmitted to humans following drinking unpasteurized milk from infected cows, causing tuberculosis and scrofula.3 Pasteurization, in which milk is heated to 161°F for at least 15 seconds and then cooled, was intended to reduce or eliminate the microbial content, thus decreasing the risk for serious bacterial infections and prolonging the shelf life.4 Since the 1920s, universal pasteurization of milk and milk products has lessened significantly the incidence of these serious infections.3,5 At the start of the obesity epidemic in the United States in the 1980s, milk was drawn into the public spotlight when the fat in whole milk was considered partly responsible for weight gain and the associated metabolic and cardiovascular complications. When the 1995 US Department of Agriculture guidelines recommended switching from whole milk to reduced-fat milk,6 consumption of whole milk plummeted in favor of low-fat varieties.