Drinking Raw Milk: More Details on the Risks
By LCDR Casey Barton Behravesh, DVM, DrPH, US Public Health Service
In response to my recent blog, Drinking Raw Milk: It’s Not Worth the Risk, we received a number of questions. Here are some of the most frequently asked questions from our readers, along with my answers.
Why focus on raw milk? What about other foods that have made people sick?
We get a lot of questions from people who are trying to decide whether or not to drink raw milk, and we want to provide them with science-based information on the risks of drinking raw milk.
I work with the group at the Centers for Disease Control and Prevention (CDC) that investigates outbreaks of foodborne illnesses caused by germs like Salmonella and E. coli O157:H7 (a dangerous form of E. coli). Over the years, we have collected extensive data based on experience investigating these outbreaks. Many different foods have been associated with recent outbreaks, such as unpasteurized juice and cider, eggs, and sprouts.
When determining if one food is riskier than another, it is important to understand how many people consume that food. For example, did you know that an estimated 4 percent of dairy products consumed in the United States are unpasteurized, based on a 2006-2007 FoodNet Population Survey, yet more than half of dairy-associated outbreaks are linked to raw milk products?
I know people who have been drinking raw milk for years, and it’s never made them sick. Why is that?
Several things can affect whether or not a person becomes sick after consuming a contaminated food or drink. These include the number and type of germs contaminating the food or drink, as well as the immune defenses of the person who consumes the food or drink.
The presence of germs in raw milk is unpredictable. The number of disease-causing germs in the raw milk may be too low to make a person sick at first, but the germs may later multiply so that there are enough to make the same person seriously ill. As seen in these videos, for some people, drinking contaminated raw milk just once could make them really sick; for others, illness comes after years of drinking raw milk.
I’ve heard that raw milk has enzymes that kill dangerous bacteria. Is that true?
No, the enzymes in raw milk are not strong enough to kill dangerous bacteria. In the United States, pasteurization is the only method routinely used to eliminate disease-causing organisms in milk.
My farmer has set up humane and sanitary conditions for raising his animals and producing raw milk. His animals are really healthy. Doesn’t this ensure that his milk is safe?
Even animals that appear healthy and clean may carry germs that can contaminate milk. Adhering to good hygienic practices during milking can reduce the risk of contaminating the milk, but it doesn’t eliminate it. If the milk is raw, small numbers of bacteria might multiply and grow in the milk before someone drinks it. No matter what precautions the farmer takes, it’s impossible to guarantee that raw milk is free of harmful germs.
What about raw milk that’s been laboratory tested for bacteria?
Negative tests do not guarantee that raw milk is safe to drink. People have become very sick from drinking raw milk that came from farms that regularly tested their milk for bacteria, and whose owners were sure that their milk was safe.
What are the statistics on outbreaks of illness related to raw milk?
Among dairy product-associated outbreaks reported to CDC between 1973 and 2009 in which the investigators reported whether the product was pasteurized or raw, 82% were due to raw milk or cheese. From 1998 through 2009, 93 outbreaks due to consumption of raw milk or raw milk products were reported to CDC. These resulted in 1,837 illnesses, 195 hospitalizations, and 2 deaths. Most of these illnesses were caused by Escherichia coli O157, Campylobacter, or Salmonella. It is important to note that a substantial proportion of the raw milk-associated disease burden falls on children; among the 93 raw dairy product outbreaks from 1998 to 2009, 79% involved at least one person less than 20 years old.
Reported outbreaks represent the tip of the iceberg. For every outbreak and every illness reported, many others occur, and most illnesses are not part of recognized outbreaks.
Keep in mind that reported outbreaks represent the tip of the iceberg. For every outbreak and every illness reported, many others occur, and most illnesses are not part of recognized outbreaks.
Can outbreaks be caused by pasteurized milk products?
Pasteurized milk and cheese products can cause outbreaks, but these are usually due to contamination that occurs after the pasteurization process. Also, the most common germ that affects pasteurized milk products is norovirus, which is typically spread from one person to another, not from animals to people. This is different from the germs that can most often contaminate raw milk like Salmonella and E. coli O157 H7, which are spread from animals to people. Also illness from norovirus typically lasts for only 2 days, whereas illness from Salmonella and E. coli is usually more serious.
For more statistics and other information, see Raw Milk Questions and Answers.
Updated on: November 18, 2011
Our family grew up on raw milk.Iam the youngest in my family, there are 10 of us. I am now 56 and none of us have had any problems realating to drinking raw milk.
The raw milk issue is not only about food safety but about food choice and the liberties that American citizens have. As with many things in life, people are allowing to take risks that may result in damage to their bodies (ie. driving, flying in a plane, sky diving, rock climbing, backpacking, swimming, etc etc.) NOTHING IS 100% SAFE. We need to get the government OUT of our kitchens and OFF our farms. The government should have no right to tell its citizens where, what, and how they are going to nourish themselves. If people want to take the risk of drinking raw milk then they need to be aware of the risks and benefits - just like any food or activity. I've been sickened by raw milk. I was in the hospital for 5 days. But I know that the benefits of raw milk outweigh the risks and I found a cleaner farm to get my milk from. It's that important! What we don't need is more government policies, inspections, etc. Consumers want a good clean product, and if farmers want customers they will provide it.
Isn't the nutritional value of raw milk much more substantial than pasteurized milk? Doesn't the extremely high heat kill off many of the nutrients the milk is suppose to provide us? Also, how are the fat molecules effected? I know they are very sensitive to heat. I imagine they are damaged or destroyed in the pasteurization process.
How about infants drinking their mothers milk? Some mothers pump their milk and keep it to bottle feed their babies.Is that safe?
The issue of raw milk is very polarizing and you have people with great passion that will defend their right to consume raw milk to the end. They are willing to take the chance of all the potential risks that you have outlined in order to consume what they feel is the only real milk product. Before pasteurization everyone drank raw milk, and while their were undoubtedly outbreaks of illness I have to believe that we have come a long way in understanding the minimalization of the risks. That being said why not work with the raw milk producers to make a safer product? Why not apply all that knowledge at the CDC toward making the product safer and more accessible to those that are going to drink it anyway? Why make producers outlaws and force them to work in the shadows or when heads are turned? There is a market for the product, you are probably not going to persuade devotees against the product by your arguments here about potential risks, so why not work to make it safer. I work in food production and have a degree in Food Science, so I have an understanding of making food safe. Pasteurization/heat is one way, but there are consequences to applying that process to some raw materials such as milk. What else can we come up with? Just applying a higher standard of cleanliness/sanitation to raw milk producers would probably knock down at least half of the outbreaks. Just something to think about until the next outbreak of supposedly safe foods,peanut or egg or ?, hits us. Thanks
Fred, there are very few foods that are absolutely safe. One reason that HACCP was applied to food production in that Astronauts could not afford to be sick. Another form of â€œsafeâ€ food are foods prepared for the immunocomprised through sterilization by irradiation. Having investigated foodborne outbreaks for the last 25 years including epidemiological studies, restaurant, warehouse, plant, and farm environmental investigation, and contributory events. The issue with raw milk is bacteria introduced from skin or fecal contamination since milk inside the udder is sterile so any bacteria that milk contains comes from random contamination. Since bacterial contamination and if the organism pathogenic or not is random, reducing bacterial can improve safety but some form of treatment whether it be pressure, heat, or irradiation pasteurization significantly improves the safety of milk (approximately 1000 fold) comparing consumption data on per serving basis versus illnesses reported for raw and pasteurized milk. As to the right to put oneself at risk by various behaviors, I have no problem with that but I think informed consent is critical that people consuming this is doing based on taste and personal preference and not health benefit. Consuming raw milk in my risk assessment is similar to smoking, chewing tobacco, not wearing seatbelts, riding motorcycles without helmet or other activities that you are putting yourself at risk where there are better, safer alternatives.