Under the Lens: Microbiologists Nicola Holden and Gil Domingue weigh in on the raw milk debate

(Press-News.org) Manchester City footballer Erling Haaland recently sparked a heated debate when he revealed that he drinks raw milk as part of a whole-food diet intended to maintain peak physical condition.

The revelation drew criticism from health experts who warned that anyone emulating the professional footballer could be leaving themselves vulnerable to harmful bacteria that are normally destroyed by pasteurisation.

US Secretary of Health and Social Services Robert F Kennedy Jr. is another high-profile advocate of raw milk who believes it offers superior nutrition, easier digestion, and protective qualities against allergies and asthma due to beneficial bacteria and enzymes. However in the USA, it was reported that greater access to unpasteurised milk was associated with more food poisoning outbreaks between 2013 and 2018.

The latest episode of Applied Microbiology International’s ‘Under The Lens’ series turns the spotlight on raw milk, with AMI Trustee, Professor Emmanuel Adukwu, interviewing two members of the learned society’s  Food Security Advisory Group with differing perspectives on the subject - Professor Nicola Holden, from Scotland’s Rural College, and Dr Gil Domingue, who runs a data analysis consultancy.

Pasteurised milk v. raw milk Addressing mounting public confusion, Professor Holden pointed out that while debate over the merits of pasteurisation is nothing new, it exists to inactivate potential food pathogens and works brilliantly at maintaining the nutritional composition of milk. The two microbiologists noted that there are no meaningful differences in the nutritional value of pasteurised milk versus raw milk.

Dr Domingue said he had become more aware of the issue of asthma and allergies and the “hint that maybe if you can preserve certain components of raw dairy milk post processing, it might help with asthmatic challenges” but expressed dissatisfaction at the slackness of terminology in some of the literature, saying the gold-plated standards are just not there yet.

Drawing parallels to COVID-19 communication challenges, the pair discussed how headline-grabbing stories mask the whole truth, providing consumers with easy-to-believe messages that often lack scientific rigour. Anecdotal evidence, such as farming families’ children experiencing fewer allergies, can spread rapidly through social media despite insufficient research to properly interpret such observations.

“That presents a challenge because as we know, trying to get to data and evidence takes a long time sometimes, but social media and media platforms move very quickly and respond very quickly, responding to whatever is driving the conversation at the time,” Dr Domingue noted.

Tantalizing papers He pointed to recent legitimate scientific investigation into the potential health benefits, noting some ‘tantalizing’ papers from central Europe.

“We’ve mentioned in our conversation and original article, the role of fatty acids and microRNAs - microRNAs weren’t heard of a few years back, but here they are and they’re obviously now featuring as epigenetic regulators if you want, of gene expression,” he said.

“But the papers we’ve cited from these studies have all stressed that raw dairy milk per se is dangerous or has a potential to be dangerous, and the more you drink of it, the more you increase the statistical chances of catching something.”

Asthma impact Professor Holden noted that one of the asthma societies had alluded to a trial looking at the impact on young children ingesting minimally processed milk as opposed to UHT.

“So there is momentum building, but I think we’re in the very, very early stages,” she commented.

One aspect that came under the spotlight was the distinction between raw milk soft cheese and aged hard cheeses in terms of microbiological safety, which matters significantly for consumer risk assessment.

Professor Holden pointed out that soft cheeses generally present a higher risk compared to aged cheese due to the environmental conditions they offer to potential pathogens, including higher water activity, different pH and temperature conditions, and different surrounding microbiota: ‘Soft cheeses are recognised as an important source of some of the most notorious pathogens, particularly in countries like Italy and France.” Although she noted that a 2024 outbreak in the USA involving cheddar demonstrated that pathogens can still survive in harder aged cheeses.

Consumer protection The pair agreed on the need for improved consumer protection through clearer product labelling, potentially similar to tobacco warning labels. They stressed the need to bring all stakeholders together—including raw milk advocates and regulatory bodies—to enforce regulations governing production and sales, which vary significantly across regions.

Dr Domingue mentioned a heart-breaking experience as part of a multidisciplinary team attending a patient who had had a miscarriage as a result of contracting an organism from raw dairy milk.

“She had drunk it thinking it was good for her health - she’d been misinformed - so there is that human impact. So I think the message for people is that there are real consequences to consuming raw dairy milk and people need to look for clear scientific evidence, and there’s a need for scientists to try to connect more with the community and the public in informing them about the risks for consumers,” he said.

Message to the public Asked by Professor Adukwu, ”If you could speak directly to a parent, a nutritionist or policymaker thinking of promoting raw milk, what would you want them to understand most?”, Professor Holden stressed: “For me, it would be, please don’t give raw milk to anyone who’s at risk for foodborne illness.

“The biggest problem about raw milk is the risk of foodborne illness, and that guidance from all of the food safety authorities is absolutely key there.”

Under The Lens is a series of fascinating science conversations in The Microbiologist magazine which will lift the lid on what microbiologists are doing to transform the world.

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