Dairy products are extremely vulnerable to contamination by disease-causing micro-organisms or pathogens. Most dairy products must be pasteurized in order to kill these bacteria.
Dairy products include milk from cows and goats (skim, homogenized, 1%, 2%), whipping cream, ½ and ½ cream, cheese made from cow and goat milk, cottage cheese, yogurt, ice cream, sour cream, butter, kefir, cream cheese, eggnog and many others. Dairy products are high in protein and moisture. These conditions provide a great environment for bacteria to grow. If harmful bacteria - pathogens - get into a dairy food, then grow and multiply to high enough numbers, then the likelihood that someone eating that food will experience foodborne illness is increased. Dairy animals (cows, goats, sheep, etc.) are known to carry pathogens that may make humans sick. As a result, raw milk (milk that is not pasteurized) and dairy products made with raw milk can be contaminated with pathogens. Because of this, it is important that all dairy products are pasteurized.
Even pasteurized milk dairy products can become contaminated. This may occur after the pasteurization step: when this occurs the contamination event is called a “post-pasteurization contamination” or a “post-processing contamination.”
Cheese outbreaks in BC have occurred due to raw cheeses and pasteurized cheeses. Types of cheese made with raw milk include blue vein cheese, Gouda cheese, and many hard varieties of cheese such as parmesan, asiago, and others. Cheeses made from pasteurized milk include feta, Havarti, mozzarella, curds, and others. Mold-ripened cheese is also made with pasteurized milk and includes brie and camembert.
Raw milk Gouda and Gouda-like cheeses have been linked to two E. coli
outbreaks in BC: one in 2013 and most recently in 2018.
- One person died, five people were hospitalized and another 23 people became ill after eating Gouda cheese that was made with raw milk in 2013. The strain of bacteria causing illness was E. coli O157:H7 known to cause serious infections and illnesses. This cheese was made in BC. The source of the E. coli was believed to be raw milk.
- Seven illnesses occurred in spiced Gouda cheese in 2018. The strain of bacteria causing illness was E. coli O121. This cheese was made in BC. The source of the E. coli was believed to be raw milk.
In both of these outbreaks, the cheese was made with raw milk. When cheese is aged for 60 days or longer, illness-causing bacteria like E. coli should all die off. However, some strains of E. coli are resistant and able to survive in low numbers in the aged cheese. Many cheese manufacturers will heat treat milk before making Gouda style cheese. This extra step helps to reduce E. coli bacteria levels in the milk before it is made into cheese.
Mold-ripened cheeses made in BC were linked to two Listeria monocytogenes
outbreaks in 2002. Over 130 illnesses occurred in two separate events that involved environmental (animal) sources that contaminated water used to make these cheeses. In the first outbreak the culture solutions used to produce the mold rind on the cheese were contaminated with Listeria
bacteria, likely transferred from farm animals to the inside of the plant to the culture solution. The second outbreak was traced to wild bird excrement in the water cistern. Both of these outbreaks were post-pasteurization contamination events. For more information read the paper described in this open source link.
Raw (unpasteurized) milk is not permitted for sale in Canada according to federal food and drugs regulations. In BC, milk safety is regulated by the BC Milk Industry Act and Regulation. Section 6 of the Act states “No sale of dairy products unless pasteurized.” Raw milk cheeses are permitted if in compliance with the Canada Food and Drug Regulations.
Pasteurization of raw milk heats the milk to kill the disease-causing bacteria. Pasteurization is the same as cooking poultry or meat and involves time and temperature to achieve reductions of bacteria. One example is to heat raw milk for a minimum of 30 minutes at 63°C.
Vitamins A and D are added to pasteurized milk to replace those vitamins that are reduced when milk fat (cream) is removed to make lower fat milk products. No other additives or preservatives can be legally added to milk.
Dr. Perry Kendall (former BC Provincial Health Officer), in a 2008 article called "Raw milk isn't safe", said, "Pasteurization of raw milk has prevented thousands of illnesses and deaths and is one of the great advances of public health of the 20th century."
BC is not immune to illnesses caused by raw milk or dairy products made with raw milk. Even though the consumption of raw milk in BC is relatively small because of our laws on raw milk sales, there have been several outbreaks caused by the consumption of raw milk in BC. (To learn more go to the raw milk illnesses tab below).
Raw milk is unsanitary and may contain feces, urine and other environmental contaminants from the source animal and its environment. Pasteurization kills most bacteria in milk.
Several studies and tests confirm that raw milk can contain a number of disease-causing organisms. The “big four" of these organisms are Listeria, Salmonella, E. coli, and Campylobacter. Many of these organisms can cause severe illnesses that, in some cases, may have permanent effects. In severe cases, illness resulting from these organisms can even cause death.
People with compromised or undeveloped immune systems, such as the elderly, people with certain chronic diseases, pregnant women and young children, are particularly vulnerable.
There is no credible or scientific evidence that the consumption of raw milk produces any measurable health benefits.
This information describes the risks of raw milk and provides evidence for illnesses caused by raw milk.