This article originally appeared in Food in Canada and is republished with the permission of the publisher.

While this year celebrates the 80th anniversary of the founding of this magazine, 2018 also marks a milestone in Canadian public health: it was 80 years ago this month that Ontario passed legislation to require the mandatory pasteurization of milk. In the early 20th century an estimated 25 per cent of the burden of food borne illness was attributed to the consumption of contaminated milk and because milk consumption was identified as the source of multiple infectious disease epidemics, many municipalities in Canada and the US required that milk be pasteurized, but Ontario was the first large jurisdiction in the world to make pasteurization of milk mandatory.

The man who played the leading role in Ontario’s decision to take this historic step was the Honourable Mitchell Hepburn, then Premier of the Province. After the worst epidemic of poliomyelitis in the province's history in the autumn of 1937, Premier Hepburn toured The Hospital for Sick Children where hundreds of children were being treated, many by artificial respiration in iron lungs. While at the hospital the Premier also visited the girl's surgical ward where he noticed several girls with bandages around their necks and inquired about the nature of their ailments. He was told that the girls had been operated on to remove tubercular glands. When he asked about the cause of glandular tuberculosis, the surgeon replied: "Drinking dirty milk". The surgeon went on to explain that since Toronto had passed a by-law requiring all milk to be pasteurized two decades before, no child born and raised in the city had ever been admitted to the hospital for tuberculosis caused by contaminated milk; all the girls he saw were from outside Toronto. The Premier thought it dreadful that children should have to suffer from something that could so easily be prevented and decided on the spot to legislate mandatory pasteurization for the whole province. During discussion of the Bill, a Member, hunchbacked and crippled by tuberculosis of the spine, rose from his chair to declare: "Gentlemen, if you have any doubt about the wisdom of this Bill, look at me. I am the victim of dirty milk". The Bill passed without a dissenting vote.

The wisdom of the Bill is no less important today. Other provinces ultimately followed Ontario's lead and, of course, it is now also a crime to sell unpasteurized milk in all of Canada under B. 08.002.2(1) of the Food and Drug Regulations. While many jurisdictions still allow the sale of raw milk, there is a broad scientific consensus that any supposed benefit of consuming raw milk is far outweighed by the clear and serious risk of its consumption. In the US, the FDA strongly endorses pasteurization, citing 39 known outbreaks associated with unpasteurized milk over a seven year period. Health Canada has been consistent: "Any possible benefits are far outweighed by the serious risk of illness from drinking raw milk." Ontario is equally clear: "Raw milk is unsafe to drink because it could contain bacteria that cause illness." A major Ontario on- farm bulk tank study of raw milk produced under the best of quality controls still found the presence of L. monocytogenes, Salmonella, Campylobacter and verotoxigenic E. Coli. The causal agent of Q Fever, C.burnetii. was found in 62 per cent of raw cow milk bulk tank samples. While most healthy people will recover in a week or so from small exposure to the pathogens that can be present in raw milk, for people with weakened immune systems such as elderly, children and people with cancer, organ transplants or HIV/AIDS, exposure is dangerous, even fatal.

While a small group of libertarians still advocate for the legalization of the sale of raw milk rejecting the "industrialization" of food production and insisting that choosing what to consume is a basic civil liberty, fortunately all Canadian legislatures have opted to protect public health and safety through science-based policy making. If he were alive today Premier Hepburn would be proud to know that the Canadian Public Health Association ranks milk pasteurization as one of the greatest public health achievements of the 20th century