How safe is the consumption of raw milk?

Milk is one of Mother Nature’s most perfect foods; however, milk quality is jeopardized when it contains life-threatening pathogens. Through science-based knowledge, procedures have been developed to make milk safer for the consumer without losing its nutritional value. Pasteurization kills harmful bacteria by heating milk to a specific temperature for a set period, eliminating microorganisms responsible for diseases such as listeriosis, typhoid fever, tuberculosis, diphtheria, and brucellosis.

 

Unpasteurized raw milk may contain harmful microorganisms, and its consumption may cause diarrhea, stomach cramping, and vomiting, and in some cases kidney failure, paralysis, chronic disorders, and even death. Despite these consequences, many people choose to consume raw milk to improve their health and feed it to their loved ones, sometimes finding themselves in a hospital bed fighting for their lives from infections caused by ingesting harmful bacteria. Examples include Guillan-Barré syndrome, which causes paralysis, and hemolytic uremic syndrome, which results in kidney failure and stroke. Contrary to popular belief, raw milk is NOT healthier and more nutritious than pasteurized milk. Most of the nutritional benefits of drinking raw milk are available from pasteurized milk without the risk of life-threatening diseases associated with raw milk.

 

Some foodborne pathogens, i.e., Listeria and Salmonella can be found in milk of infected cows. However, the main sources of contamination with other harmful germs (Fig. 1) include feces, milking equipment, cows’ skin, insects and rodents, and other environmental sites. Pasteurization is the only method to eliminate potential pathogens from contaminated raw milk, and since milk is an ideal medium for bacterial growth, manipulation and processing of pasteurized milk must be conducted under strict, hygienic conditions to prevent post-pasteurization contamination.

 

Even when a laboratory test shows no contaminants in a raw milk sample, the result is only applicable to the sample that was submitted for testing, as contaminations can still occur in other batches of milk on the same farm that had previously shown negative results. Also, raw milk from organic farms or grass-fed cows has the same risks of contamination simply because most of the foodborne pathogens originate from cows’ feces, regardless of how they are fed.

 

In a review conducted by the CDC, 26 states reported 81 outbreaks due to the consumption of raw milk between 2007 and 2012, causing 979 illnesses and 73 hospitalizations (Fig. 2). The percentage of these outbreaks increased from 2% (2007-2009) to 5% (2010-2012); 81% occurred in states where sale of raw milk is legal. Of these, 71% originated directly from the farm, 13% from licensed sellers, and 12% from cow-share programs.

 

 

A raw milk outbreak in one state can lead to outbreaks in neighboring states. For example, a 2011 outbreak in NC where sale of raw milk is illegal was traced back to a “buying club” in SC where sale is legal. Similarly, a 2012 Campylobacter outbreak in PA where raw milk sale is legal was linked to cases of foodborne illnesses in MD, WV, and NJ, where sale is illegal.

 

 

To conclude, an increasing number of people are consuming unpasteurized raw milk based on its unsubstantiated enhanced nutritional qualities, taste, and health benefits. This trend continues even though numerous studies have shown very clearly that raw milk can be contaminated by a variety of pathogens associated with human illness. Epidemiologic and outbreak data are clear: human diseases associated with consumption of raw milk are on the rise and are considerably higher than those from pasteurized milk. Given continued interest in the consumption of raw milk, efforts to educate policy makers/regulators/legislators on food safety hazards associated with consumption of raw milk are necessary so that appropriate microbial standards for raw milk can be established. One sure way to prevent raw milk-associated foodborne illness is for consumers to refrain from drinking unpasteurized milk.

 

This article was originally published in the Southeast Quality Milk Initiative Quarterly, Spring 2017.