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Back to Product Quality

Raw Milk

Does pasteurization destroy the nutritional properties of milk? Is it healthier to consume raw milk? Pasteurization has very little impact on the nutritional value of milk and is essential to preserve its safety.

In addition, all milk in Canada must be pasteurized and it is illegal to sell or buy raw milk.

Although farmers take necessary measures to ensure the safety of their milk, they cannot guarantee that it is bacteria-free until it is pasteurized. Pasteurization is important for human safety1 and is one of the most beneficial measures to protect the health of consumers. This process has been required by provincial law for decades and was added to the national Canadian Food and Drugs Act in 1991.

Pasteurization is the process of heating milk at temperatures high enough to kill potential pathogens that can cause disease. Pasteurization does not involve the use of any additives. This process not only makes milk safe to drink, it increases the shelf life (the amount of time a product can be kept before it spoils) because it destroys organisms that cause spoilage. There are three pasteurization methods:

  • high temperature short time (HTST)
  • batch-holding
  • ultra-high temperature (UHT).

In addition to being safe, pasteurized milk is also fortified with vitamin D contrary to raw milk which contains only very small amounts of this vitamin. Studies have shown that calcium absorption is unchanged with pasteurization and that vitamin A, vitamin D, riboflavin and niacin are not affected by heat.2 During the pasteurization process there is a minimal loss (approximately 10%) of thiamine and vitamin B12.2 But because losses are small in comparison to the large amounts of the B vitamins in milk, milk is still considered a source of these nutrients. About 20% of vitamin C is lost during pasteurization, but this loss is not nutritionally significant since milk is not an important source of vitamin C to begin with.

Some people have wondered about the effect of pasteurization on proteins and enzymes. While it is true that heating above 60°C can cause some proteins to break down,3,4 research has shown that heat-denatured milk proteins may even be more easily digested.5 Some people believe that raw milk is healthier and more digestible because it contains “live” enzymes that are deactivated by pasteurization. This is not true. Although some enzymes are denatured by pasteurization, the same thing occurs in the acidic environment of the stomach, and these enzymes are not required for digestion anyway.6

Raw milk is unsafe because it can contain pathogens such as E. coli, salmonella, campylobacter, tuberculosis bacillus and listeria. Many people across Canada have become seriously ill after consuming raw milk.5 Symptoms of infection with pathogens potentially carried in raw milk can include headache, abdominal pain, diarrhea, fever, nausea and vomiting. There may be increased risk in people with weakened immune system, children, pregnant women and elderly people. It is for this reason that regulations have been put in place that make it illegal to sell or distribute raw milk in Canada.

References

  1. Leedom JM. Milk of nonhuman origin and infectious diseases in humans. Clin Infect Dis, 2006. 43(5): p. 610-5.
  2. Haddad GS and Loewenstein M. Effect of several heat treatments and frozen storage on thiamine, riboflavin, and ascorbic acid content of milk. J Dairy Sci, 1983. 66(8): p. 1601-6.
  3. Rolls BA and Porter JW. Some effects of processing and storage on the nutritive value of milk and milk products. Proc Nutr Soc, 1973. 32(1): p. 9-15.
  4. Douglas FW et al. Effects of ultra-high-temperature pasteurization on milk proteins. J Agric Food Chem, 1981. 29(1): p. 11-5.
  5. White FM and McCarthy ME. Raw milk and health in humans. Can Med Assoc J, 1982. 26(11): p. 1260-2.
  6. Potter ME et al. Unpasteurized milk. The hazards of a health fetish. JAMA, 1984. 252(15): p. 2048-52.

Keywords: raw milk


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