London - Has pasteurised milk reached its sell-by date?
Over the past few decades, raw - or unpasteurised - milk has been seen as bacteria-ridden Russian roulette in a bottle.
But a growing body of evidence now suggests that pasteurisation may be robbing us of vital protection against serious allergies, as well as destroying a range of life-enhancing nutrients.
While you can legally buy “raw” milk from farmers, fresh milk sold in Britain’s High Streets must, by law, be pasteurised — a technique that involves heating it to 72c for 25 seconds.
This eliminates E.coli and other potentially lethal pathogens such as campylobacter, salmonella and listeria.
However, the process seems to also destroy beneficial elements that protect us from a host of ailments, in particular allergies in children and adults.
A study of more than 1 100 children by paediatric allergy specialists at Ludwig Maximilian University in Munich, Germany, found that those who regularly drank unpasteurised farm milk were significantly less likely to develop asthma.
The findings of this large-scale, long-term (six-year) study are in line with earlier, smaller studies. But the German study also points to omega 3 fatty acids as the substance in raw milk that may be key to the benefits. Tabea Brick, one of the immunologists who led the research, says that these play a crucial role in enabling the body to create chemicals that reduce harmful inflammation.
Asthma is essentially an inflammatory allergic reaction in the airways of the lungs.
“Fresh, unprocessed cow’s milk has a higher content of omega 3 than does pasteurised, homogenised [where it’s treated to stop the cream separating] or low-fat milk,” she says inthe Journal of Allergy and Clinical Immunology.
“This factor partly explains why children who consume the unprocessed product are less likely to develop asthma.”
Our bodies can’t make omega 3 fatty acids, but they can be obtained from foods such as dairy and fish.
Nevertheless, the authors of the study held back from recommending switching to untreated milk.
They worry that the benefits may be outweighed by any potential danger from dangerous stomach bugs.
Instead, the researchers urge that milk producers develop processing methods that are gentler than pasteurisation, that can both protect the beneficial components in milk, while eliminating any potentially dangerous pathogens.
Pasteurisation was first performed in 1862, by Louis Pasteur and Claude Bernard. It was first used industrially in Germany in the 1880s. But for decades it was controversial. It is still not actually compulsory in England and Wales.
In the Twenties, only 1.5 percent of Britain’s milk was pasteurised. The majority of our milk was still raw in 1939. This remained true in many small UK towns and rural areas well into the Fifties.
In the latter half of the 20th century, pasteurisation was the subject of bitter debate in the UK. Food scientists, such as the eccentric television pundit Magnus Pyke, lambasted as “irrational” and “mystical” those who opposed the sterilisation process on the grounds that it destroyed milk’s natural goodness.
But now medical research is discovering raw milk’s ability to alleviate severe allergy.
Last November, researchers at London’s Population Health Research Institute reported in the journal PLOS ONE that UK children who drank unpasteurised milk had a significantly lower risk of rhinitis, hay fever and allergic conjunctivitis.
In a similar vein, when dermatologist Dr Donna Torley, at Southern General Hospital in Glasgow, examined the results of 24 previous research reviews in 2013, she found that consuming unpasteurised milk plays a significant role in reducing the risk of children developing eczema.
The benefits may even be passed on in the womb.
Mothers who drink unpasteurised milk are less likely to have children who suffer childhood asthma and other allergies, according to a study published in the journal Current Opinion.
Scientists have also discovered more about how pasteurisation diminishes the benefits of natural milk.
A study by Australian pharmacists, published in the International Journal of Food Sciences and Nutrition, found the sterilisation process can cut levels of vitamin D by up to 20 percent.
And a report in the British Medical Journal in 2014 cited evidence indicating that pasteurisation kills beneficial bacteria that boost the gut’s ability to absorb nutrients. The bacteria also produce vitamin K, which helps blood to clot and bones to grow properly.
Dr Hilary Longhurst, a consultant clinical immunologist at Barts Health, believes, however, that we should stick with pasteurisation as the “simplest and most cost-effective way to protect public health”.
She adds: “People have forgotten the dangers of infectious diseases such as tuberculosis and foodborne infections.”
Indeed, worries persist about the safety of unpasteurised milk.
In 2014, the Food Standards Agency (FSA) said it had found three separate incidents involving six cases of E.coli infection that were “potentially linked” to drinking it. The cases involved five children aged one and 12 years old and one adult aged 28.
The FSA says unpasteurised milk should not be consumed by children or people with weakened immune systems.
However, rigorous testing found no trace of the harmful bacteria in the farms’ milk sampled.
And last year an in-depth safety review by the FSA ruled that while raw milk should continue to be sold, this could only be direct to consumers on specifically licensed farms, in farm shops and at farmers’ markets.
The FSA believes this is the best way to maintain safe hygiene standards.
Daily Mail