What pasteurisation does
Standard pasteurisation heats milk to about 72°C for 15 seconds, then cools it quickly. This kills disease-causing bacteria while keeping the taste close to fresh milk. It is not the same as boiling, and it does not turn milk into a different food.
Nutrition: smaller differences than you might think
- Protein, fat, calcium and lactose: essentially unchanged
- Some B vitamins and vitamin C: small losses, but milk is not an important source of vitamin C anyway
- Enzymes: some, such as alkaline phosphatase, are destroyed (this is how labs check milk has been pasteurised). Humans make their own digestive enzymes, so this matters less than is often claimed
- Lactose intolerance: studies have not found that raw milk is easier to digest for people who are lactose intolerant, because both contain the same lactose
The real risk
Even milk from clean, healthy, well-run farms can carry bacteria such as E. coli O157, Campylobacter, Salmonella and Listeria. Most healthy adults who get ill recover, but these infections can be severe, especially in small children (where E. coli can damage the kidneys) and in pregnancy (where Listeria can harm the baby).
Who should avoid raw milk
The UK government’s guidance names these groups:
- Children and infants
- Pregnant women
- People aged 65 and over
- Anyone with a weakened immune system, for example during cancer treatment
The rules in the UK
In England, raw drinking milk can only be sold directly by registered farms (at the farm gate, by vending machine or online), at farmers’ markets, or by milk rounds, and it must carry a health warning. Wales and Northern Ireland also restrict sales to direct farm-to-customer routes, while sales of raw cow’s milk to the public are banned in Scotland. Elsewhere, laws vary widely, so check locally.
Why the old milk diet books liked raw milk
Writers such as Bernarr Macfadden preferred milk “unaltered since coming from the cow”. At the time, many dairies added chemical preservatives such as formaldehyde, so his worry was partly about adulterated milk, which is no longer an issue. You can read his reasoning in Chapter III of The Miracle of Milk.
If you choose raw milk anyway
- Buy only from a registered, regularly tested farm
- Keep it at or below 4°C and use it within a few days
- Never give it to the vulnerable groups listed above
- If you plan to drink large amounts, such as on a milk diet or GOMAD, pasteurised milk is the much safer choice
Source: GOV.UK: Raw drinking milk; Food Standards Agency.
This article is general information, not medical advice. Please speak to your doctor or a registered dietitian before making big changes to your diet.