Is raw milk more nutritious than pasteurised?

No, in any way that matters. Pasteurisation reduces vitamin C and some B vitamins by roughly ten to twenty per cent, and milk is not a meaningful source of either. Protein, calcium, fat, vitamin A, vitamin B12 and riboflavin are essentially unaffected. The claims that pasteurisation destroys beneficial enzymes overlook that milk enzymes are denatured by stomach acid before they could do anything, whether or not the milk was heated. The claim about beneficial bacteria describes an uncontrolled mixture of whatever organisms happened to be present, which is not a probiotic in any meaningful sense and may include pathogens. If the nutritional argument were sound, it would show up in comparative analyses, and it does not.

Why do people say they can drink raw milk when pasteurised upsets them?

Possibly because something real is happening, but not because of pasteurisation. The commonly given explanation — that pasteurisation destroys lactase — is impossible: lactase is made by your small intestine, not present in milk, so nothing done to the milk can affect it. A randomised crossover trial in people with self-reported lactose intolerance found no difference between raw and pasteurised milk in symptoms or hydrogen breath testing. What might genuinely differ is the beta-casein variant: milk from some breeds is predominantly A2 rather than A1, and A1 digestion releases a peptide that has been linked to gastrointestinal symptoms in some trials. Fat globule structure, freshness and expectancy may also contribute. Usefully, all of these can be tested with pasteurised A2 milk, which carries none of the microbiological risk.

How large is the actual risk?

Larger than for almost any other food relative to how little of it is consumed. In countries where raw milk is legal it represents a very small share of dairy consumption and causes the substantial majority of dairy-associated outbreaks, with a risk per unit consumed that is orders of magnitude higher than pasteurised milk. The pathogens are not trivial: Campylobacter, which occasionally leads to Guillain-Barré syndrome; Shiga toxin-producing E. coli, which causes haemolytic uraemic syndrome in five to fifteen per cent of infected children, with kidney failure and sometimes permanent damage; Listeria, which causes miscarriage, stillbirth and neonatal death in pregnancy; Salmonella; and Brucella. This pattern is consistent across countries and decades, which makes it hard to explain away as a reporting artefact.

What about the evidence that farm milk protects against asthma?

This is the strongest argument advocates have and it deserves a proper answer. European cohort studies did find lower rates of asthma and allergy in children raised on traditional farms, with farm milk consumption among the exposures associated with protection. The problem is that farm children experience a whole package of early-life exposures — livestock contact, stable dust, endotoxin, microbial diversity — and the protective effect is strongest for that whole package rather than for milk alone. Studies have not isolated milk as the operative factor, and the proposed protective components, such as certain whey proteins, have not been shown to require raw consumption. Research into delivering those components without the pathogens is ongoing, which is the appropriate response to a real but confounded signal.

How does GMJ News cover raw milk?

GMJ News covers pasteurisation methods and the alkaline phosphatase verification test, the specific pathogens and their severe outcomes including haemolytic uraemic syndrome and listeriosis in pregnancy, outbreak surveillance data across jurisdictions, the mechanistic impossibility of the lactose tolerance claim and the trial that tested it, the farm effect on allergy and why it does not isolate milk, A2 beta-casein as a plausible alternative explanation for individual tolerance, H5N1 in dairy cattle, and the regulatory variation between countries. Part of PHIG's contested science and food safety programmes.

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Raw Milk

Q: Does H5N1 in dairy cattle change anything?

It adds a genuinely new consideration that did not exist before. Highly pathogenic avian influenza H5N1 has been detected in dairy cattle with very high viral loads in the milk itself. Infectious virus has been recovered from raw milk samples, and experimental exposure of animals to raw milk from infected cows has produced infection. Pasteurisation has been shown to inactivate the virus, which is reassuring for the commercial supply. Whether drinking raw milk actually transmits H5N1 to humans has not been established, and it would be wrong to overstate it. But it is an active and evolving situation, and it emerged at exactly the moment raw milk was being promoted more widely — which is worth knowing when weighing the decision.

GMJ News knowledge hub · last reviewed September 2026 · Georgian Medical Journal

Summary Statistics Glossary GMJ news FAQ Documents Organizations Research

Raw milk is a settled scientific question being actively re-litigated, and the honest summary is uncomfortable for those promoting it: pasteurisation removes pathogens without meaningfully degrading nutritional value, and unpasteurised milk is responsible for a share of dairy-associated foodborne outbreaks vastly disproportionate to its share of consumption, with documented outbreaks of Campylobacter, Shiga toxin-producing E. coli, Listeria, Salmonella and Brucella (WHO). The specific claims made for it do not survive examination: pasteurisation does not destroy lactase — milk contains none — so it cannot explain improved tolerance; heat-labile losses are confined to modest reductions in vitamin C and some B vitamins, neither of which milk is a significant source of; and beneficial bacteria are not reliably present. The population most attracted to raw milk overlaps substantially with the population least able to tolerate its consequences, since children, pregnant women, older adults and immunocompromised people carry the highest risk of haemolytic uraemic syndrome, miscarriage and invasive listeriosis, and the emergence of H5N1 in dairy cattle has added a further consideration.

Key messages

SETTLED: pasteurisation removes pathogens without meaningfully degrading nutrition

Pasteurisation heats milk to 72°C for 15 seconds, or 63°C for 30 minutes in the batch method, which reliably inactivates Campylobacter, Salmonella, Listeria, Shiga toxin-producing E. coli, Brucella, Coxiella burnetii and Mycobacterium bovis. Nutritional consequences are modest and confined to heat-labile vitamins: a reduction of roughly 10-20% in vitamin C and some B vitamins, in a food that is not a meaningful source of either. Protein, calcium, fat, vitamin A, vitamin D in fortified products, and the great majority of B12 and riboflavin are unaffected.

THE OUTBREAK DATA ARE DISPROPORTIONATE AND CONSISTENT

Raw milk accounts for a small fraction of dairy consumption in countries where it is legal, and a large fraction of dairy-associated outbreaks — surveillance analyses have found unpasteurised dairy responsible for the substantial majority of dairy outbreaks despite representing a very small share of consumption, with an outbreak risk per unit consumed orders of magnitude higher. This pattern is reproduced across jurisdictions and decades, which is unusual consistency for a food safety question and difficult to attribute to reporting artefact.

THE SPECIFIC CLAIMS DO NOT SURVIVE EXAMINATION

Lactose tolerance: pasteurisation does not destroy lactase because milk contains no lactase — the enzyme is produced in the human small intestine, so heat treatment cannot affect it, and a blinded crossover trial found no difference in lactose intolerance symptoms between raw and pasteurised milk. Beneficial bacteria: raw milk contains whatever organisms were present, which is not a defined probiotic and may include pathogens. Enzymes: milk enzymes are denatured by stomach acid regardless of pasteurisation. Asthma and allergy: the farm effect observed in cohort studies is confounded by whole-farm exposure and does not isolate milk.

THE HIGHEST-RISK GROUPS OVERLAP WITH THE MOST-TARGETED AUDIENCE

Children under five, pregnant women, older adults and immunocompromised people carry the greatest risk of severe outcomes: haemolytic uraemic syndrome from Shiga toxin-producing E. coli, which causes acute kidney injury and can require dialysis and cause lasting renal impairment; listeriosis in pregnancy, causing miscarriage, stillbirth and neonatal sepsis with high case fatality; and invasive salmonellosis. Raw milk is frequently promoted for children specifically on the grounds of superior nutrition, which inverts the risk calculus precisely.

H5N1 IN DAIRY CATTLE ADDED A NEW CONSIDERATION

The detection of highly pathogenic avian influenza H5N1 in dairy cattle, with very high viral loads in milk, introduced a novel concern. Pasteurisation has been shown to inactivate the virus in milk. Infectious virus has been recovered from raw milk, and experimental animal exposure has produced infection. Whether raw milk consumption transmits H5N1 to humans is not established, and the risk should not be overstated — but it is a live and evolving question, and it arrived precisely as raw milk consumption was being promoted more widely.

WHAT IS LEGITIMATE IN THE UNDERLYING CONCERN

The instincts driving raw milk interest are not all misplaced and dismissing them wholesale is unproductive. Interest in less industrialised food, in supporting small-scale local producers, in animal welfare, and in scepticism about consolidated industrial food systems are defensible positions that can be pursued without consuming unpasteurised milk. Some people also genuinely tolerate raw milk better, which may reflect A2 beta-casein content in some herds, fat globule structure or simple expectancy rather than pasteurisation status — and there are pasteurised A2 and traditionally produced options that address the preference without the microbiological risk.

Key statistics

72°C / 15s

standard pasteurisation, reliably inactivating Campylobacter, Listeria, STEC, Salmonella and Brucella

WHO/Codex

10-20%

reduction confined to vitamin C and some B vitamins — nutrients milk is not a major source of

FSA/EFSA

Disproportionate

unpasteurised dairy causes the majority of dairy outbreaks from a small share of consumption

CDC/EFSA surveillance

No lactase in milk

pasteurisation cannot destroy an enzyme milk does not contain — the tolerance claim is mechanistically void

Ann Fam Med RCT

Highest risk

children under 5, pregnancy, older adults, immunocompromised — HUS, listeriosis, invasive salmonellosis

WHO/CDC

H5N1

high viral loads found in milk from infected dairy cattle; pasteurisation inactivates the virus

FDA/USDA/WHO

Raw milk — where the disagreement actually lies

Source: Bars show strength of supporting evidence. This is a settled food safety question being re-litigated rather than a genuine scientific dispute.

Glossary of key terms

Pathogens of concern in raw milk
MicrobiologyCampylobacter jejuni is the most frequent cause of raw milk outbreaks, producing severe enterocolitis and, in a small proportion, Guillain-Barré syndrome weeks later. Shiga toxin-producing E. coli, including O157:H7, causes bloody diarrhoea and haemolytic uraemic syndrome in around 5-15% of infected children, with acute kidney injury requiring dialysis and long-term renal sequelae in some survivors — antibiotics are contraindicated as they may increase HUS risk. Listeria monocytogenes causes invasive disease with high case fatality, particularly in pregnancy, neonates, older adults and the immunocompromised. Salmonella, Brucella abortus and melitensis, Coxiella burnetii causing Q fever, Mycobacterium bovis and Yersinia enterocolitica complete the principal list.

Pasteurisation methods and testing
Food technologyHigh-temperature short-time pasteurisation heats milk to 72°C for at least 15 seconds in a continuous plate heat exchanger, the dominant commercial method. Low-temperature long-time or batch pasteurisation uses 63°C for 30 minutes. Ultra-high-temperature treatment at 135-150°C for a few seconds produces shelf-stable milk with more pronounced flavour and vitamin changes. The alkaline phosphatase test provides verification: this enzyme is naturally present in raw milk and is inactivated at slightly higher thermal conditions than Coxiella burnetii, the most heat-resistant relevant pathogen, so a negative phosphatase result confirms adequate pasteurisation. Thermisation at lower temperatures reduces but does not eliminate pathogens and does not satisfy pasteurisation standards.

The farm effect and the hygiene hypothesis
Immunology/EpidemiologyEuropean cohort studies including PARSIFAL and GABRIELA found lower rates of asthma, hay fever and atopic sensitisation among children raised on traditional farms, with farm milk consumption among the associated exposures. This is the strongest evidence raw milk advocates possess and deserves a serious answer rather than dismissal. The difficulty is isolation: farm children also experience early and intense exposure to livestock, stable dust, endotoxin, a diverse microbial environment, and differ in family structure, antibiotic use and other factors — and the protective association is strongest for whole-farm exposure rather than milk alone. The proposed protective components, including whey proteins and microbial diversity, have not been shown to require raw consumption, and trials of alternative delivery are ongoing.

The lactose intolerance claim
PhysiologyThe claim that pasteurisation destroys lactase and therefore causes lactose intolerance is not merely unsupported but mechanistically impossible: lactase is produced by the brush border of the human small intestine, and milk does not contain it. Nothing done to milk can affect the enzyme the drinker produces. A randomised crossover trial in adults with self-reported lactose intolerance compared raw milk, pasteurised milk and soy milk and found no difference in symptoms or hydrogen breath test results between raw and pasteurised milk. This is an unusually clean example of a popular claim that can be refuted from first principles before any trial is consulted, and it is worth using as a teaching case for exactly that reason.

Regulation across jurisdictions
PolicyApproaches vary widely, which is sometimes cited as evidence of scientific disagreement and generally is not. The United States prohibits interstate sale of raw milk for direct consumption while individual states permit varying degrees of intrastate sale, farm-gate sale or herdshare arrangements. Scotland prohibits sale entirely; England, Wales and Northern Ireland permit direct farm-gate and farmers market sale with mandatory warning labelling. Australia and New Zealand prohibit sale for human consumption. Several European countries permit sale with strict testing regimes, and France maintains substantial raw milk cheese production under regulated conditions. Raw milk cheese aged beyond defined periods is treated differently in many jurisdictions because ageing, acidity and salt reduce but do not eliminate risk.

A2 milk and the tolerance question
Dairy scienceSome people genuinely feel better on certain milks, and there is a plausible mechanism unrelated to pasteurisation. Beta-casein exists in A1 and A2 variants differing by a single amino acid; digestion of A1 releases beta-casomorphin-7, which has been proposed to cause gastrointestinal symptoms in susceptible individuals. Trials comparing A1 and A2 milk have shown differences in symptom scores and transit in some studies, with the evidence still developing. Milk from certain breeds and herds is predominantly A2. The clinically useful point is that people who tolerate a particular farm's raw milk better may be responding to breed, fat globule structure, freshness or expectancy rather than to the absence of pasteurisation — and pasteurised A2 milk allows that preference to be tested without microbiological risk.