The rate of food-poisoning outbreaks caused by unpasteurized, or raw, milk and dairy products is 150 times greater than outbreaks linked to pasteurized milk, according to new research.
The studies were published last week by the Centers for Disease Control and Prevention (CDC) in the journal Emerging Infectious Diseases.
But alas, that number might be closer to 151 by now. A new outbreak emanating from bad raw milk in Pennsylvania, coincidentally coinciding with the release of this CDC report, so far has sickened nearly 100 people in four states.
It's not as if pasteurized milk is perfectly safe. There were 48 disease outbreaks from contaminated pasteurized milk and cheese resulting in thousands of illnesses and one death between 1993 and 2006, the period analyzed by the CDC. [Top 10 Mysterious Diseases]
The sale of raw milk, however, has led to 73 disease outbreaks, two deaths, and many permanent disabilities during the same period — alarming numbers considering that raw milk constitutes less than 1 percent of all dairy sales. States where raw milk sales are legal had twice as many outbreaks, the study found.
Outbreaks stem from many kinds of bacteria, such as Campylobacter, Salmonella, E. coli, and Listeria.
These outbreaks may be on the rise, too, the CDC says, given the growing popularity of raw milk products. In the 20 U.S. states that ban raw milk sales, willing consumers can circumvent the laws by forming cow-sharing cooperatives or by buying raw milk under the guise of pet food.
Raw milk comes straight from the dairy animal's teat to you with little processing, the way nature sort of intended this otherwise rare interspecies-sharing of lactating fluid. Humans throughout history, however, rarely guzzled milk by the glassful the way we do today. Milk usually was soured into yogurt, curdled into cheese, or made into whey or other products that could keep longer without refrigeration.
Those who did drink raw milk, an important source of protein and other nutrients, usually lived on a farm with cows or other dairy animals and benefited from a fresh product.
As milk drinking became more popular in the 20th century, governments began instituting the practice of pasteurization, which flash-boils the milk to kill most of the bacteria, good and bad. This made milk safe for consumption in cities and other regions far from a dairy farm.
But forced pasteurization in the United States in the early 20th century created a faction that has grown stronger in recent years. Proponents of raw milk argue that it is healthier, tastier and safer than conventional milk if produced correctly.
Health benefits debatable
The "healthier" argument remains unproven. Pasteurization only slightly reduces the nutritional value of milk. The reduction in vitamins B12 and E and, actually, an increase in vitamin A in pasteurized milk are of little concern because the levels are inherently so low and easily can be obtained in other foods, according to a systematic review of 40 studies published in 2011 in the Journal of Food Safety. Pasteurization reduces vitamin B2, or riboflavin; yet so too does sunlight, and raw milk sold in glass bottles loses some of its riboflavin this way.
Conversely, raw milk usually doesn't contain vitamin D, which is added to conventional milk. The main source of this vitamin is sunlight, but many people in northern climates do not get enough sun during the winter months. Without a supplement, children in particular would be at risk for poor bone development. [Infographic: The Power of Vitamin D]
Whether raw milk can boost the immune system also is debated. A study published in 2011 in the Journal of Allergy and Clinical Immunology demonstrated that drinking raw milk was associated with lower asthma rates among farm children in rural Germany and Switzerland. Yet the effect might be due to farm living more than the milk, since research has shown that living on farms (and having pets) can stimulate kids' immune systems.
Ban it or improve it?
Taste is another thing, though. Raw milk and cheeses do have a distinctive taste, which raw-milk advocates say they are denied as a result of perverse laws that sacrifice personal liberties in the name of public health.
That is, there is no call to ban raw vegetables or seafood. In 2011, 50 people died from contaminated bean sprouts from Germany and 29 people died from contaminated cantaloupes from California, according to CDC data. Pasteurized cheese contaminated with listeria killed 52 people in 1985, the deadliest bacterial food-borne outbreak recorded in U.S. history.
Raw-milk advocates argue that unpasteurized milk from grass-fed cows raised humanely in open fields and handled hygienically is inherently safer than the milk from large and crowded commercial farms, where disease is rampant. Unfortunately, the new CDC research doesn't support this notion, because outbreaks from bad raw milk are emanating from seemingly clean and humane farms.
"Restricting the sale of raw milk products is likely to reduce the number of outbreaks and can help keep people healthier," said Robert Tauxe, CDC's deputy director of the Division of Foodborne, Waterborne and Environmental Diseases, in a press statement tied to this latest study.
In light of the CDC analysis, the best advice for raw-milk connoisseurs is to think of raw milk as analogous to raw eggs, meat, fish or oysters. Also, think twice before giving raw milk to children, as they constitute the majority of the victims of raw-milk illnesses.
Christopher Wanjek is the author of the books "Bad Medicine" and "Food At Work." His column, Bad Medicine, appears regularly on LiveScience.
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Christopher Wanjek is a Live Science contributor and a health and science writer. He is the author of three science books: Spacefarers (2020), Food at Work (2005) and Bad Medicine (2003). His "Food at Work" book and project, concerning workers' health, safety and productivity, was commissioned by the U.N.'s International Labor Organization. For Live Science, Christopher covers public health, nutrition and biology, and he has written extensively for The Washington Post and Sky & Telescope among others, as well as for the NASA Goddard Space Flight Center, where he was a senior writer. Christopher holds a Master of Health degree from Harvard School of Public Health and a degree in journalism from Temple University.