They reported their findings in the New England Journal of Medicine. “Vegan cheese substitutes have been recommended as an alternative to raw milk cheese for people at risk of listeriosis infections, including pregnant women.
We report an outbreak of listeriosis in France between April and December 2022, which affected four pregnant women who had premature births (at a mean of 32 weeks of pregnancy) and the case of a 38-year-old person with a compromised immune system who suffered from meningoencephalitis (inflammation of… Brain and meninges; note) fell ill,” wrote Alexandre Leclercq from the Institut Pasteur in Paris and his co-authors in the world’s most respected medical journal a few days ago (DOI: 10.1056/NEJMc2400665).
Three-year-old child in the hospital
After a warning from the French authorities, further cases were discovered in Belgium (in a three-year-old child), in Germany (in a person with pregnancy-related sepsis) and in the Netherlands (meningitis in a baby following birth), the German Medical Journal also wrote. The scientists sequenced the genetic makeup of the listeria that had caused the serious infections: the bacteria were actually identical. When those affected were questioned, it turned out that they had consumed vegan cheese from the “Jay & Joy” brand from a French manufacturer. In January 2023, the producer recalled several varieties of the “Jay & Joy” brand.
The product recall affected a vegan goose liver substitute product as well as substitute products for brie or blue cheese. “Made from raw almond, cashew or coconut milk, these alternative semi-soft substitute products imitate other dairy products (e.g. Camembert, goat and blue cheese),” wrote the scientists involved in the investigation of the affair.
No pasteurization
A possible problem, according to the experts: “Such products are marketed as healthier than cheese made from (animal) milk and as free of food-borne pathogens because they are plant-based. But they are not subjected to hygiene measures such as pasteurization, to keep contamination in the raw material, in production or following production under control.”
The types of milk that come from plant sources are apparently potentially a good breeding ground for listeria. In a comparative study cited by Marc Lecuit (Institut Pasteur/Paris) in the New England Journal of Medicine, listeria in milk made from nuts even grew significantly faster than in cow’s milk (Food Microbiology 2023; DOI: 10.1016/j.fm.2022.104143).
The physicochemical properties of these products (such as pH and water activity) would enable the growth of L. monocytogenes, Lecuit wrote. At least in the United States, vegan substitutes continue to be inappropriately promoted as safe alternatives to raw animal milk products. Salmonella contamination was also detected. Manufacturers should be aware of the risks of pathogens in vegan cheeses too.
Listeria is known to cause life-threatening invasive infections, especially in older people or people with weakened immune systems. Only recently in Wiener Neustadt, the managing director of a now closed cheese factory stood before a criminal court for listeria cases (grossly negligent homicide in five cases and grossly negligent grievous bodily harm in two cases) and was sentenced to 13 months in prison.
