Health experts have issued a warning over trendy ‘raw’ cheeses after a man died from listeria poisoning, as the popularity of unpasteurised dairy surges in the UK.
Whether it’s Brie de Meaux, Comté or classic Parmigiano Reggiano, many of the world’s best-known cheeses are made using raw milk, which has not been heat-treated to kill bacteria.
Supporters say this preserves flavour and beneficial microbes – but scientists warn it can also allow dangerous pathogens to survive.
West Sussex painter Roger Parkes fell seriously ill and died in February 2023, days after eating a ‘Valentine box’ of artisan cheeses bought by his wife, Carina.
Following his death, Wiltshire-based producer The Old Cheese Room recalled batches of its Baronet Reblochon. An inquest later concluded Mr Parkes died from multiple organ failure and meningitis linked to listeria infection.
His widow is now suing the company for more than £200,000.
But just how risky is raw cheese – and should we be worried about listeria?
Professor Catherine Rees, a microbiologist at the University of Nottingham, explains that listeria is a particular concern in raw-milk cheeses because it can continue to grow even at refrigeration temperatures.
Whether it’s Brie de Meaux, Comté or classic Parmigiano Reggiano, many of the world’s best-known cheeses are made using raw milk
‘Listeria is the one everyone in the industry worries about,’ Professor Rees told The Telegraph.
‘Unlike many other bacteria, it can survive and slowly multiply in the fridge.’
Listeriosis – caused by the bacterium Listeria monocytogenes – is typically mild, with flu-like symptoms such as fever, muscle aches and nausea.
But in vulnerable groups, including the elderly, pregnant women and those with weakened immune systems, it can become life-threatening, spreading to the bloodstream and brain, causing sepsis or meningitis.
The bacteria is usually killed during pasteurisation, meaning it is more commonly associated with raw dairy products as well as ready-to-eat foods such as deli meats, smoked fish and pre-packaged sandwiches.
Many foods can harbour the organism and contaminated produce may not look or smell spoiled.
Latest UK Health Security Agency figures show 179 cases of listeriosis were reported in England and Wales in 2024, with 28 deaths recorded among non-pregnancy-related cases.
Seven outbreaks were investigated, linked to a range of foods including smoked fish, chocolate mousse, strawberry desserts and pre-packed sandwiches.
Roger Parkes (pictured) fell seriously ill and died in February 2023, days after eating a ‘Valentine box’ of artisan cheeses
Following Mr Parkes’ death The Old Cheese Room, a Wiltshire artisan firm, issued a product recall on their ‘Baronet’ Reblochon
However, experts stress that infection remains relatively rare given the huge quantities of food consumed each year.
Food safety specialist Sylvia Anderson told The Telegraph that strict regulations are in place across the UK food industry.
‘There are controls, testing and serious penalties for companies that fail to meet safety standards,’ she said. ‘If listeria is found in a product, something has gone wrong in the production process.’
Even so, contamination can occur at multiple stages – including after pasteurisation – through poorly cleaned equipment or cross-contamination.
Industry figures have also pointed out that pasteurisation removes not only harmful bacteria but also beneficial microbes that contribute to flavour.
According to Neal’s Yard Dairy, a London artisanal cheese retailer, ‘the worst thing about pasteurisation is also the best thing about pasteurisation: it kills microorganisms in milk’ – including both harmful and beneficial ones.
But experts warn that lapses in hygiene at any point in the supply chain can allow dangerous bacteria to spread.
Consumers also play a role in reducing risk. Listeria is widespread in the environment and can contaminate food at home, particularly if products are left out at room temperature or kept beyond their use-by date.
Food safety guidance recommends keeping raw-milk cheeses refrigerated and consuming them promptly after opening.
Once removed from the fridge, they should not be left out for extended periods, as bacteria can multiply rapidly.
Thorough cooking will kill listeria, significantly reducing the risk of infection.
While most people can safely enjoy artisan cheeses, health experts advise those in higher-risk groups to take extra caution – or avoid unpasteurised products altogether.
And as the popularity of raw dairy continues to grow, experts warn that even small lapses in food safety can have serious – and sometimes fatal – consequences.
