Confession–I grew up drinking raw milk, and as far as I know, I never got sick off it. I also like the taste of raw milk better than home-pasteurized milk, which tends to get overcooked and taste gross. However, I also remember straining straw, dust, and occasionally dried manure out of the milk (stuff falls off the goat’s bellies, etc.), which means our milk was very far from sterile. I now study foodborne bacteria, so I can give you a list of top suspects for what was in that (and any) delicious raw milk. Here it is:
(1) Listeria monocytogenes (Listeria): this bacterium is so common in nature that almost every academic paper begins by saying some variation of “Listeria monocytogenes is a foodborne pathogen which is ubiquitous in the environment…” Seriously, this pathogen lives in the soil, in decaying leaves, in the intestines of mammals and bird, and just about anywhere else you can imagine (4). Listeria is also highly stress tolerant, and can grow in the refrigerator, even if it’s set to the appropriate temperature (40 degrees Fahrenheit) (4). Listeria especially likes to infect unborn children and cause late-term miscarriages, so pregnant women should never drink raw milk or raw milk cheeses (1,4). Listeria is also a major problem for the elderly and people whose immune systems are compromised because of cancer, diabetes, HIV, or organ transplants (4).
(2) Salmonella enterica (Salmonella): better known for contaminating eggs or raw chicken, Salmonella is found in up to 9% of raw milk samples (3). While most Salmonella won’t kill you, illness from Salmonella can require hospitalization; regardless, spending several days vomiting or having diarrhea (or both) is not fun (4).
(3) Escherichia coli (E. coli): E. coli can cause a mild illness like Salmonella or kidney-destroying complications (hemolytic uremia syndrome) or death, depending on the variety of E. coli involved (4). Up to 4% of raw milk samples may contain E. coli in the U.S. (3).
(4) Campylobacter jejunum (Campy) (4): most people have never heard of this bacterium, but it is found in up to 13% of milk samples in the U.S (3). It generally causes a very mild illness, but patients can occasionally develop long-term complications, such as the autoimmune disease Guillan-Barre syndrome or a form of arthritis (4).
(4) And more… (check out the resources listed at the bottom).
Maybe, like me, you have never gotten sick, so it seems worthwhile to keep drinking raw milk (I don’t drink raw milk anymore, by the way). I hope I’ve convinced you otherwise, but if not, here are some final considerations:
- Studies of the effect of pasteurization on the nutrients in milk haven’t found any significant differences in nutritional quality between the two (3).
- 13% of raw milk in the U.S. contains either Listeria or Campy (3). Approximately 9% or raw milk samples in the U.S. contain Salmonella (3). More than 30% of samples in some studies had at least one foodborne pathogen in them (3).
- Pregnant women & their unborn children, small children (under 6 years), and the elderly (>65 years) are most likely to become seriously ill from any foodborne illness.
Final thought: what benefits of raw milk would be great enough to outweigh the risks? You’ll have to decide this yourself, but I highly recommend buying a thermometer and starting to pasteurize milk. Even if it doesn’t taste quite as good.
Sources and additional information:
(1) FDA discussion of raw milk: https://www.fda.gov/Food/ResourcesForYou/Consumers/ucm079516.htm
(2) Brief discussion from the Centers for Disease Control and Prevention: https://www.cdc.gov/foodsafety/rawmilk/raw-milk-questions-and-answers.html
(3) A longer discussion of safety, nutrition, and purported allergy benefits of raw milk: https://www.cdr.wisc.edu/sites/default/files/PDFs/director_corner/Raw_Milk_Consm__Risks_Benefits.pdf
(4) FDA’s Bad Bug Book (2013). Great source of information on individual foodborne bacteria and viruses: https://www.fda.gov/downloads/Food/FoodborneIllnessContaminants/UCM297627.pdf