An Invented Disease?December 31, 2007
The Listeria ScareDecember 31, 2007
Posted on the FDA website is a PowerPoint presentation by John F. Sheehan, BSc (Dy), JD, Director of the FDA’s Division of Dairy and Egg Safety, entitled “On the Safety of Raw Milk (with a word about pasteurization).” The 69-slide PowerPoint was first presented at the 2005 meeting of the National Commission on Interstate Milk Shipments by Cindy Leonard, MS. With the blessings of the FDA, many federal and state government officials have presented or cited this PowerPoint presentation in testimony and official documents that argue against raw milk.
The FDA presentation cites 15 studies on specific outbreaks to bolster its claim that raw milk is dangerous and that pasteurization is the only way to ensure the safety of Nature’s perfect food. In addition, a number of slides are devoted to debunking claims that raw milk is more nutritious than pasteurized.
Researchers for the Weston A. Price Foundation have prepared a slide-by-slide rebuttal of the FDA PowerPoint. This rebuttal is now posted at realmilk.com (Response to the FDA: A Point-by-Point Rebuttal to the Anti-Raw Milk PowerPoint Presentation by John F. Sheehan), along with a complete listing of references. The rebuttal is designed to serve as a tool for raw milk advocates—to use in testimony, lobbying activities and legal actions—showing the slippery, dubious science upon which arguments for pasteurization are based.
In its arguments on raw milk safety, the FDA makes two important mistakes: addressing the safety of raw milk outside the context of general food safety and addressing pasteurization as the only means of making milk safe. That the consumption of raw milk carries some risk is undeniable. The question is whether raw milk carries a unique risk that distinguishes it from other foods ordinarily consumed—such as pasteurized milk, produce, hot dogs or deli meats. The FDA does not make this comparison. The second question that must be addressed is how milk can best be made safe. The FDA considers pasteurization the only option and ignores other measures such as improved sanitation and pasture-based farming.
What emerges from careful analysis is the fact that all of the 15 reports cited as associating outbreaks of foodborne illness with raw milk are seriously flawed. Fourteen of the 15 studies produced either no valid positive milk sample or no valid statistical association. In fact, 11 of the studies, lab analyses revealed no pathogen at all in the milk and in one study, the strain of organism associated with the outbreak did not match the strain found in the milk. In seven of the 15 studies, the FDA misrepresents the findings of the study authors. In one of these, the authors themselves concluded that raw milk was unrelated to the outbreak and in another, the authors concluded that regular raw milk consumption was protective!
Most importantly, not one of the studies cited offers evidence that pasteurization would have prevented the outbreak.
The $64,000 Question
The important question is this: what is the rate of illness from raw milk on a per-serving basis compared to that from pasteurized milk on a per-serving basis? Given the absence of reliable statistics on the number of raw milk drinkers, and given the shoddiness of the reports purporting to demonstrate that raw milk caused illness, this question is impossible to answer. However, in September, 2003, the FDA, USDA and CDC jointly released a report comparing the risk of listeriosis carried by various foods. The report estimated how many people were likely to contract listeriosis from a given food per year on an absolute basis and on a per serving basis.
On a per-serving basis, this report estimated that deli meats are 10.8 times more dangerous than raw milk and that non-reheated hot dogs are 9.2 times more dangerous than raw milk. Since deli meats are so commonly consumed, on an absolute basis they carry 515 times as great a risk as raw milk. The FDA has yet to inform us that “hot dogs and deli meats are inherently dangerous.”
Pasteurization Not Foolproof
Conspicuously absent from the FDA report is any reference to the mounting evidence that pasteurization is not in any way a foolproof means of eliminating pathogens. For example, in 1999, Czechoslovakian researchers Binderova and Rysanek showed that if pre-pasteurization contamination is high, dangerous levels of L. monocytogenes and E. coli O157:H7 can survive high-temperature, short-time pasteurization. Various Bacillus and Clostridium species and Mycobacterium paratuberculosis may also survive pasteurization. Heat treatment can cause bacteria to enter into a state of dormancy from which they can potentially recover in the human intestine. This state of dormancy can cause typical laboratory culture techniques to underestimate the actual presence of E. coli in heat-treated milk 100-fold. These and other organisms can also contaminate milk after pasteurization. The production of cheese or other processed dairy products allows additional opportunities for contamination. Between 1980 and 2005, 41 outbreaks were reported to the CDC, attributing 19,531 illnesses to the consumption of pasteurized milk and milk products.
Raw Milk “Myths”
The PowerPoint concludes by addressing a number of “myths” about the health benefits of raw milk and the dangers of pasteurized milk. Yet many of the statements that the FDA calls “myths” are in fact clearly demonstrated in the scientific literature. Other such statements are poorly formulated but refer to something that is nevertheless true and important. While a few of the assertions may be unsubstantiated, the fact is that there is an overwhelming set of observations recorded in the scientific literature justifying interest in the benefits of raw milk.
For example, FDA cites as a “myth” the claim that pasteurized milk is more allergenic than raw milk. Although there may be insufficient evidence to claim that pasteurized milk is more allergenic than raw milk, there does exist evidence that raw milk prevents the development of allergic disorders in general. An important recent study published in The Lancet (Riedler et al, 2001), indicates that children who drink “farm milk”—independent of other types of exposure to farming environments—had a 52 percent lower risk of asthma, a 57 percent lower risk of having had at least one wheeze attack in the past year, a 76 percent lower risk of hay fever, a 58 percent lower risk of having had a runny nose and itchy eyes in the past year, and an 85 percent lower risk of allergies to cows, dust mites, cat dander and pollen.
The authors noted that “farm milk” is “usually raw” and contains more bacteria than pasteurized milk. They suggested that “the ingestion of non-infectious microbial components,” in raw milk or the milk’s effects on intestinal flora might protect against the development of allergies. There exist many more anecdotal reports of potential raw milk benefits that the scientific establishment has not yet addressed.
FDA argues that pasteurization does not destroy the nutrients in milk. Yet, according to the reference cited by the FDA, between 90 and 100 percent of milk folate is bound by a protein that doubles its intestinal absorption. This protein is inactivated by pasteurization. Vitamin B12 is also bound by heat-sensitive proteins whose functions are unknown. Vitamin B6 that has been damaged by heat interferes with the activity of the intact vitamin and aggravates the symptoms of its deficiency.
Beta-lactoglobulin, a heat-sensitive protein in milk, increases the intestinal absorption of vitamin A. Vitamin D is also present in milk in a protein-bound form, but the effects of pasteurization on the protein and the effect of the protein on the bioavailability of the vitamin are unknown. There are likely many other factors affecting nutrient bioavailability that are altered by pasteurization.
Given the bias exhibited in the FDA PowerPoint presentation, consumers should not be at the mercy of funding institutions that control the research on milk, both raw and pasteurized, nor of government agencies that promote the agenda of pasteurization; they should have the right to put into their bodies the milk of their own choosing.
Our federal and state governments, for their part, should be helping farmers produce raw milk safely, and the FDA should be providing us with a sober and balanced report on the safety and merits of raw milk rather than a piece of sensationalist propaganda.
Sources of Bias
In the 15 cases the FDA sites on foodborne illness attributed to raw milk, the following sources of bias emerge:
- Some questionnaires used in investigations of foodborne illness ask about many foods and some ask about only a few—but all ask about raw milk.
- Often, equally likely or more likely sources of infection—such as hot dogs in the case of Listeria—are ignored when investigators discover that some of the patients had consumed raw milk products.
- In many instances, case-control studies are used to show that those who became ill were statistically more likely to use raw milk than those who did not become ill. While this is valid grounds for hypothesizing that raw milk is to blame, it is not valid grounds for confirming it. Nevertheless, investigators often claim that raw milk caused an outbreak on this basis alone, even when all milk samples tested negative for the organism.
- Since the availability of raw milk is limited, its consumption can often be a marker for visits to specific farms, purchases from specific street vendors, or associations with specific groups of people. Because organisms that cause foodborne illness can also be spread through contact with animals, animal manure, infected people, and other foods prepared by infected people, statistical associations with raw milk may arise in cases where the actual cause of the outbreak is contact with animals or their manure, person-to-person contact, or the consumption of other foods sold by raw milk product street vendors.
- Although people can acquire an infection from consuming milk and cheese, infected people can also spread an infectious organism to uncontaminated milk, cheese, and other foods by drinking milk out of the container and biting into or handling other foods. Demonstrating that leftover cheese or milk is contaminated, then, means very little if it is not also demonstrated that products from the original source are contaminated with the same strain.
- Milk products can become contaminated at many different points over the course of their production, both before and after pasteurization. Cheese products can become contaminated during the cheese-making process, especially if the facility and implements are not properly sanitized and separated from other sources of contamination, such as raw meats.
- For this reason, even in cases where an outbreak is genuinely traced to a raw milk product, the question must be asked: “Would pasteurization have prevented this outbreak?”
- Often times the answer is, “We don’t know,” or simply, “No.”
Lactoferrin In Raw Milk
The FDA PowerPoint tries to dispel several “myths” about the compounds in anti-microbial raw milk. Slide 44 disputes the claim that lactoferrin in raw milk “is an enzyme-based pathogen killer.” Our response is as follows:
- According to a recent review in the Journal of Experimental Therapeutics and Oncology, there is evidence that a portion of the lactoferrin molecule acts as a serine protease. Since serine protease activity is enzymatic and since it is responsible for part of the molecule’s antibacterial effects, lactoferrin is technically an “enzyme-based pathogen killer.”
- Lactoferrin, according to this review, exhibits fungistatic, bacteriostatic, bactericidal, and antiviral properties and inhibits the growth of parasites.
- It is effective against Escherichia coli, Salmonella typhimurium, Bacillus subtilis, Pseudomonas aeruginosa, Vibrio cholerae, Haemophilus influenzae, Staphylococcus aureus, Klebsiella pnemoniae, Candida albicans, Candida crusei, Tinea pedis, Toxoplasma gondii, Plasmodium falciparum, Herpes simplex, hepatitis C virus, human papillomavirus, and various other pathogens.
- It is not effective against gram-positive bacteria such as Bifidobacterium and Lactobacillus species. These species are friendly to the human intestine.
- In 2003, the FDA approved the use of a lactoferrin-based anti-microbial spray to combat E. coli O157:H7 contamination in the meat industry. The FDA press release praised the product as an innovative way to protect the nation from foodborne illness.
- “Innovative technology is a critical building block in preserving the strong foundation of the U.S. food supply,” said Dr. Lester Crawford, Deputy Commissioner of the Food and Drug Administration. “We must continue to encourage scientific research and new technology to maintain this nation’s safe food supply.”
- Since the dawn of mammalian history, nature has provided this “innovative technology” to nursing infants to protect their vulnerable and sensitive digestive systems from the insults of invading pathogens. Perhaps this is one reason why responsibly handled raw milk rarely leads to genuine cases of foodborne illness.
This article appeared in the Winter 2007 edition of Wise Traditions, the quarterly journal of the Weston A. Price Foundation.