The stuff is so dangerous that shops are banned from selling it directly to consumers in England and Wales. And it is banned completely in Scotland, Australia and around half the states in the US.
So who is right? What is the truth about raw milk? And how can something so natural be so dangerous?
All the milk you buy in the supermarket, and most of the milk delivered to your doorstep, is heat-treated, or pasteurised, to kill harmful bacteria. Typically, milk is heated to 72c for at least 15 seconds, hot enough to make milk safe without ruining its flavour.
Raw milk is simply the stuff that's expressed from a cow (or goat or sheep) and bottled without any heat treatment.
When you see a glass of raw milk, the first thing you notice is the colour. It's more yellow than pasteurised - although the colour, and flavour, will change throughout the year, depending on what the cow is eating.
Then you spot the layer of cream. Nowadays, most pasteurised milk is homogenised, or forced through tiny holes to break up the fat and distribute it evenly, meaning we no longer get that inch of cream on top of the milk that people of a certain age remember from their childhood.
Raw milk isn't homogenised. After a couple of days in the fridge, the cream rises to the top to form a solid layer.
British dairy farmer Steve Hook, who produces 12,000 pints - around 40 to 45 per cent of all the UK's raw milk - from his family's farm in Hailsham, East Sussex, says the taste is vastly superior. "It is more creamy, and it has a clean taste," he says.
His customers, who are willing to pay around £2.60 (NZ $6) a pint, also buy it for health reasons.
"Around 80 per cent of people who think they are lactose intolerant are actually intolerant to pasteurised milk," he says. "Raw milk contains natural enzymes and bacteria that help you digest lactose."
Those enzymes are destroyed during pasteurisation, he says, making it more difficult for the body to process.
Supporters of raw milk say it has more vitamins and higher concentrations of "good" bacteria - the sort found in "probiotic" drinks and yoghurts - that can help digestion.
Many consumers drink it to help with eczema, asthma and hay fever. "A lot of customers tell me their eczema has gone in three weeks of drinking raw milk," says Mr Hook.
Many of the claims are anecdotal. But there is some scientific evidence for unpasteurised milk's benefits.
In 2011, a Swiss study of 8,000 children in Germany, Austria and Switzerland found those drinking raw milk were 41 per cent less likely to develop asthma and half as likely to develop hay fever than children drinking the pasteurised stuff.
The researchers said the higher amounts of whey protein in raw milk could protect against allergies. However, they were unsure why the proteins prevent asthma and hay fever.
One theory is that pasteurised milk contains lots of dead bacteria, which may trigger inflammation in the body. Another is that the good bacteria in raw milk help protect against allergic reactions.
A review of the evidence surrounding raw milk in 2011 by Liane Macdonald, of the University of Toronto, concluded that it has higher levels of Vitamins B12, E, B1 and folate. These findings have been seized on by supporters of raw milk - but there's a catch.
Most studies showing that raw milk prevents allergies were done on children living on farms, not those in towns and cities. It's likely life on a farm, with all that exposure to animals and dirt, is what protects children from allergies, not raw milk.
Experts also point out that most of the extra nutrients in raw milk are easily available from our diet.
A review of raw milk in the Journal of Food Control in 2013 by Belgian scientists found that its potential health advantages, and improved flavour, were outweighed by the risks.
The U.S. Centres For Disease Control goes further. It says: "There are no health benefits from drinking raw milk that cannot be obtained from drinking pasteurised milk that is free of disease-causing bacteria."
And those bacteria can be deadly.
In Australia, it can be sold only as "bath milk" - not fit to drink, but suitable for cleansing the skin.
In practise, it is little more than a way to get around the ban and a huge majority of customers who buy raw milk in Australia drink it. Tragically, this resulted in the death of a three-year-old in Victoria last year. Raw milk was banned in Scotland in 1983 after 12 people died from food poisoning linked to it.
Without heat treatment, milk can carry bacteria for TB, salmonella, campylobacter, listeria and E.coli 0157. The microbes get into milk through contamination with cow faeces, from the animals' skin, from udder infections or poor farm hygiene. Diseases such as TB are transmitted directly via milk.
The risks from raw milk are greatest for children, the elderly and those with weak immune systems.
Last year the Food Standards Agency warned parents not to give raw milk to children after five youngsters were taken to hospital with E.coli poisoning.
The FSA said two children, aged ten and 12, fell ill after drinking raw milk sold by Barton Farm Dairy in Barnstaple, Devon. Two other farms linked to the food poisoning of three youngsters, plus a 29-year-old customer, were unnamed.
All are believed to have recovered and the FSA and local council are still considering what action to take against the farms.
Because of well-founded health fears, raw milk is tightly regulated in England and Wales. Supermarkets and shops cannot sell it - just farmers directly to consumers.
All bottles must carry the warning: "This milk has not been heat treated and may therefore contain organisms harmful to health."
Only registered farmers can sell the stuff. They have to be regularly and rigorously inspected.
Mr Hook says: "Our herds are milked in a hygienic environment using sterile milking equipment."
Of all the milk sold in England and Wales, just one pint in 10,000 is unpasteurised. However, demand is growing, according to Mr Hook.
Last year, after a public consultation, the FSA provisionally agreed to allowed it to be sold from vending machines in stores.
The FSA believes that if raw milk is allowed on sale alongside ordinary milk in supermarket fridges, many consumers will buy it without being fully aware of the dangers. And the more people who buy it, the greater the risk of someone falling ill.
Vending machines, plastered with warning signs, are a compromise that "allows wider, but still controlled access to raw drinking milk" according to the FSA. A final decision is due to be taken later this month.
Food poisoning experts are wary about making raw milk more widely available. Prof Christine Dodd, microbiologist at Nottingham University, says: "If you live on a farm and drink it all your life you probably develop some tolerance. The more easily available it is, the higher the risk that people will come down with disease."
The mainstream dairy industry in the UK also opposes making raw milk more widely available. It says the incidence of food poisoning went down after Scotland's ban.
The FSA says it is stuck in the middle between giving consumers choice and protecting them.
Linden Jack, head of its food hygiene policy, says: "Unpasteurised milk could contain harmful bacteria that would normally be killed by heat treatment. However, we recognise that many people prefer to drink raw milk so those controls need to balance consumer protection with choice."
Farmer Mr Hook thinks vending machines are the answer to making raw milk more easily available without risking health.
He also notes that no food is 100 per cent safe. It's a good point. Chicken is a major source of salmonella and campylobacter, yet consumers are trusted to wash their hands and scrub kitchen surfaces after handling raw poultry. No one proposes banning poultry sales.
The raw milk controversy divides consumers, farmers and scientists. The health claims are likely to be exaggerated, but there do seem to be benefits. And there's no question the taste is superior.
But is that worth the small, but real chance of food poisoning?
It boils down to how much risk you and your family are prepared to take for a glass of the real white stuff.
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- Daily Mail
