Is raw milk worth the risk?

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There’s no getting around it. Milk comes from the busier end of a cow.

You’ve got the business end of the alimentary system, a tail spreading manure all-round the place and the udder, the source of our milk, is right there in the middle.

Cows aren’t great at hygiene, especially when there is a lot of them in confined spaces, and if you want to get safe milk from a cow you need to be careful.

And that’s not all. Both cows, and the humans who are doing the milking, are susceptible to infection and some of these infections can be transmitted via milk.

Hygiene matters and dairy can be dangerous. Historically, a lot of people have died from diseases transmitted by milk. Most of them children.

Pasteurisation was the breakthrough that allowed us to stop these deaths. But advocates for raw milk say that pasteurisation is destroying the nutritional benefit of milk and that we should go back to raw milk.

So, what should we do? Is raw milk worth the risk?

Dairy’s Dirty Secret: Why Milk Needs Saving

Milk is a highly nutritious substance. After all, it’s mean’t to nourish young mammals and provide them with the fuel they need to grow.

Unfortunately this also makes milk a very good substrate for bacterial growth. This means that unless milk is treated with the utmost care it can carry a high microbial burden.

Milk can carry bacteria such as Campylobacter, Salmonella, Listeria monocytogenes, E. coli, Cryptosporidium and Staphylococcus aureus. All of these microbes can make you very ill indeed.

Cows can also pass zoonotic diseases such as tuberculosis, brucellosis and typhoid fever through their milk. In other words, if a cow is sick it can pass their infection to humans through their milk.

A tragic example of this was the UK Tuberculosis crisis, between 1912 and 1937, where 65,000 people died from tuberculosis contracted from cow’s milk.

It almost goes without saying that milk producers need to be very careful to ensure that they are not producing tainted milk. Pasteurisation is a key step in modern milk production because it destroys any disease causing microbes immediately that are present after milking.

Urbanization and the 19th-Century Infant Mortality Crisis

One of the effects of the industrial revolution, that kicked off in the late 18th century, was the movement of a lot of people from the country to the city.

Mass migration caused overcrowding and strained inadequate infrastructure. When combined with pollution from the new factories and plants, the inevitable result was a host of health problems for the rural refugees.

Urbanisation and Milk Production

Urbanisation also had consequences for milk production.

Because there was no refrigeration, milk had to be produced in close proximity to it’s consumers. So, where milk production had formerly taken place on dairy farms, it was now occurring in overcrowded cities.

Somewhat surprisingly, to modern ears, milk production became associated with distilleries. An industry that didn’t place a lot of importance on milk quality.

Cows were kept in crowded sheds and fed “slop”, a by-product of the distilling process, that resulted in very unhealthy cows; ulcerated mouths, tails falling off, tuberculosis of the lung and intestines, that kind of thing.

The milk coming from these cows was cloudy and sometimes, amazingly, pale blue in colour. This poor-quality milk was then distributed to consumers without the benefit of adequate refrigeration.

Distillers, acting as business so often does, didn’t try to improve the conditions of the dairy cows, instead they responded by trying to ‘tart up’ the milk, seeking to improve it’s appearance using sugar, eggs and even plaster of Paris.

The Shift Away from Breast Feeding

Urbanisation also led to a decrease in the frequency of breast-feeding. Mostly a consequence of women leaving the home and entering the workforce.

The babies still needed to be fed though. So, to compensate, baby formulas based on commercial cow’s milk were adopted.

The increased consumption of inadequately cooled and appalling poor-quality milk inevitably led to a lot of dead infants. Particularly so in the summer months when the temperature was conducive to microbial growth in tainted milk.

The effects of bad milk on children during the warmer months was so noticeable that is was referred to as “summer diarrhea“.

Germ Theory and Louis Pasteur’s Revolutionary Process

Fortunately for human beings not rich enough to enjoy appropriate hygiene and access to clean food and water, in lock-step with the industrial revolution came a revolution in our understanding of the causes of disease.

The development of germ theory led directly to the development of antibiotics, vaccines and pasteurisation.

First developed by Louis Pasteur, who lent his name to the process. Pasteurisation was based on the idea that liquids like beer, wine and milk could be briefly heated to kill micro-organisms responsible for spoilage and disease.

Given the harm caused by urban milk production the practical application of pasteurisation was obvious. Ultimately the combination of mandated pasteurisation and improvements in milk production intended to decrease the contamination and proliferation of micro-organisms in milk got us to where we are today.

In the 21st century milk is a relatively low risk food. We can grab a bottle of milk from the supermarket and be reasonably sure that we’re bringing harm to ourselves or our families.

Until people started drinking raw milk again.

Raw Milk vs. Pasteurised Milk: What Do the Risk Statistics Show?

Over recent years people have started advocating for the benefits of raw milk. Influencers, of course, niche dairy farmers and holistic health promoters have suggested that pasteurisation destroys the nutritional benefits of milk and that we should all be drinking raw milk.

If you go to a raw milk advocacy site you’ll see a long list of arguments that would take a much longer work than this to go through and refute. But most of the arguments boil down to:

• Pasteurised milk is not risk free
• Raw milk is no riskier than pasteurised milk
• Pasteurisation destroys the health benefit of milk and children who drink raw milk have better outcomes when it comes to asthma, allergies and respiratory illnesses
• We’ve been drinking unpasteurised milk for thousands of years so how can it be so bad?

So lets go through and have a look at some of these claims.

Pasteurised Milk is Not Risk Free

In this the raw advocates are completely correct. Pasteurised milk is not risk free and you can still get sick from drinking pasteurised milk.

One area of concern is the bacterium Listeria monocytogenes. This is a serious food-borne infection that can cause severe symptoms like septicaemia, meningitis and endocarditis (heart inflammation).

The problem with Listeria that is that it is still able to grow in the temperatures around 4$\degree$C, the temperature our fridges are generally set. So, if pasteurised milk is infected with Listeria after it has been pasteurised it can continue to grow and cause food poisoning.

Listeria is a very specific risk for pregnant woman, infection can cause severe complications, miscarriage, or stillbirth during pregnancy. Which is why pregnant women are advised to not eat soft cheeses, pate, deli meats and precooked poultry, among many other things.

If anything, the risks associated with pasteurised milk only highlights how dangerous milk can be.

Raw milk is no riskier than pasteurised milk

This is where the raw milk advocates can become a bit disingenuous. Often they will compare the amount of hospitalisations and deaths caused by raw milk and pasteurised milk.

Generally this comparison favours raw milk.

The comparison, though is normally done with raw figures and doesn’t take into account the massive difference in the amount of raw and pasteurised milk that is drunk.

In the USA, only 4.4% of the population had drunk raw milk once in the past year, and a tiny 1.6% having raw milk once per month or more often.

A low end estimate for the amount of milk consumed in the USA per year is around 16 billion litres. So, using simple maths and rounding up to 5% of people drinking raw milk, 15.2 billion litres more pasteurised milk was consumed than raw milk.

If you correct comparisons for this disparity raw milk drinkers are 840 times more likely to contract a food-borne illness from raw milk than those drinking pasteurised milk and 45 times more likely to end up in hospital.

Pasteurisation Destroys the Health Benefits of Milk

For pasteurisation to destroy the health benefits of raw milk we need there to actually be some health benefits to drinking raw milk.

To date the only health benefit with any evidence is that it may be protective against allergies, asthma and respiratory tract diseases when consumed by children.

There are a lot of studies, mostly observational, in children raised in rural areas and on farms showing some effect. That is children who drink raw milk have a lower incidence of these types of diseases than those raised in urban areas who don’t drink raw milk.

Because they are often cross-sectional these studies have caused a bit of debate, there are plenty of potential confounding factors, but there does seem to be some evidence that this is a real effect (for a good review see here).

As for adults there is absolutely no evidence for any benefits that can be gained by drinking raw milk over pasteurised milk. And when you think about it this makes perfect sense. For most people on the planet, their own bodies assume that they will not be drinking milk as an adult and stop producing lactase.

Most adults on the planet can’t drink milk, raw or pasteurised.

This is the paradox of raw milk. The only people who look like they can benefit from raw milk are the very same people who are most at risk of the food-borne diseases it can transmit, that is children.

If only there was another safer source of milk that we could feed our young children that could provided a similar protection.

We’ve Been Drinking Raw Milk for Thousands of Years

It’s true, we’ve been drinking raw milk for thousands of years. It’s also true that in pre-pasteurisation England, between 1912 and 1937, 65,000 people died of tuberculosis suspected to be contracted via cow’s milk (see here and here).

More generally, for most of human history, well up to the 18th century, only 50% children made it to the age of 15.

If the cows milk didn’t get you in childhood then measles, cholera, diphtheria, whooping cough, influenza, tuberculosis or smallpox would get you anyway. Would anyone have even noticed if children were dying because of cows milk?

We’d certainly notice today because the global childhood mortality rate in 2022 was 4.3%, and in some countries, like Japan and Norway, it was around 0.03% (see here if you want to read about where these numbers are coming from).

Increases in human life expectancy have to a great part been the result of our amazing success in reducing infant mortality rates, and pasteurisation was a part of that success not raw milk.

Conclusion

The decision to eat any food stuff involves an assessment of the risks and benefits of eating that food.

Raw oysters kill more people than raw and pasteurised put milk together. But we don’t feed oysters to new-borns, pregnant women avoid them, and we don’t sit down to a plate of oysters for breakfast every day.

Raw milk advocates over-emphasise the benefits of raw milk while trying to down-play the risks. That the risks are pre-dominantly borne by more vulnerable members of the community, children, pregnant woman and the elderly or infirm, is what makes raw milk advocacy so objectionable.

Pasteurisation gives us a fighting chance if we want to consume milk that is more than a day or two old and has been transported far from where it was produced in anything less than perfect conditions.

Given the questionable benefits and the known and well documented risks of drinking raw milk, or even pasteurised milk, pasteurisation makes as much sense now as it did in the 19th century.