♨️ Boiling

Boiling milk means heating it to boiling point to kill the microbes in raw milk that has not been pasteurised. Raw milk can contain Campylobacter, Cryptosporidium, E. coli, Listeria, Brucella and Salmonella. Those most at risk are children under five, people over 65, pregnant women and anyone with a weakened immune system.

Where there are no fridges, FAO lists boiling straight after milking among the ways to preserve milk. The European agency EFSA notes that people who buy raw milk from vending machines are usually advised to boil it, and this removes the microbial risks. In Germany, a farm may sell raw milk directly only with a clearly visible notice, "Rohmilch, vor dem Verzehr abkochen" ("Raw milk, boil before consumption"), and only if it was milked that day or the day before.

Many traditional foods rely on boiled milk. In India, dahi is cultured from it, and hot milk is curdled with acid to make chhena (chhana). The thick skin called malai that forms on boiled milk is skimmed off and cooked down into ghee. Boiling milk easily boils over, which gave rise to the Ukrainian saying "once burned by milk, you blow on water".

Boiling or pasteurising? Both heat milk to kill microbes, but they are used in different places. Pasteurised milk, treated at the dairy, is already safe, and the FDA notes that pasteurisation destroys pathogens without a noticeable loss of nutritional value. Boiling is the home step for raw milk that has not been pasteurised, from a farm or a vending machine; EFSA notes buyers of vending-machine milk are usually advised to boil it. Neither treatment helps with milk allergy, and neither is a cure for lactose intolerance.

On a pack or a vending machine the key words are “raw milk” and “pasteurised milk”. Pasteurised milk, from the chilled shelf of a supermarket or a delicatessen, is ready to drink and needs only the fridge. Raw milk from a farm gate or a vending machine should be boiled before use, and the seller should say so clearly; in Germany the notice “Rohmilch, vor dem Verzehr abkochen” is required. Raw milk has no protected-origin mark that replaces boiling.

Why it matters to you. Pasteurised milk is already safe, but raw milk from a farm or vending machine is best boiled. The US FDA explains that pasteurisation destroys pathogens without a noticeable loss of nutritional value, and raw milk cures neither lactose intolerance nor allergy. Boiling does not remove allergens either: it will not help people who are allergic to milk protein.