Cereulide in baby food has caused a global scandal. Image: imago images
Infants should only receive the best nutrition. But what is that actually? Two experts about powder milk, additives that are not always necessary and the poison cereulide, for which every second import containing ARA oil has been tested since Tuesday.
March 4, 2026, 2:44 p.mMarch 4, 2026, 2:44 p.m
“Formula” means milk powder for infants in English. That fits: it’s a complex mixture, almost the magic formula for new life. It’s logical that the products are tested more strictly than any other food. A poison like cereulide, which caused the global baby food scandal, shouldn’t remain undetected for long.
Furthermore, the bacterium that produces it is Bacillus cereus, widespread. Food manufacturers and catering establishments have long been under scrutiny for this common source of food poisoning. Cereulide is often found in cereals, pasta or rice because the bacteria likes starch. Bacillus cereus does not reproduce when stored dry, but the spores survive and can become active again if conditions change. Above all, the toxin from the bacteria remains in the products if they secreted it during production.
The fact that this is also possible with infant formula is a very late realization after the cases of sick babies that have become known in the last few weeks.
Lots of sugar for a rapidly growing brain
The powder consists mainly of carbohydrates in the form of lactose, i.e. milk sugar. Unlike normal sugar, this is first broken down into glucose and galactose in the intestine and is therefore not harmful to teeth. No other mammals provide their offspring with as many carbohydrates (7%) as primates, which include humans: they are necessary for rapid brain growth.
The protein content of cows’ milk is more than twice as high at 3.5 percent. Because calves have to grow quickly. Marine mammals, on the other hand, provide their offspring with an above-average amount of fat so that an insulating layer can be built up quickly.
When baby powder didn’t exist, people sometimes tried cow’s or goat’s milk when a mother couldn’t breastfeed and a wet nurse couldn’t help out. But all the protein in the form of casein clumps together in the stomach acid. “Human children have difficulty digesting it, which leads to stomach cramps,” says human biologist Thierry Hennet from the University of Zurich. His research focus is breast milk.
Today it has long been known which proteins are the right ones for babies and how high the fat content should be (4 percent). The research now revolves around the substances in the remaining 0.3 percent of breast milk: minerals, vitamins, antibodies, fatty acids and the famous oligosaccharides. These short-chain carbohydrates usually cannot be digested, but as prebiotic fiber they promote healthy intestinal flora.
Not everything that is advertised is super healthy
“When it comes to oligosaccharides, a lot of it is pure advertising,” says Hennet. “The artificially produced substances are not the same as the real ones.” There are also 100 to 200 types of them in breast milk and these make up the magical mix. If you only take a few of them, the effect will be different. “It is impossible to create the same complexity artificially,” says Hennet.
There is more evidence of benefit for fatty acids, including the omega-6 fatty acid, in which the toxin cereulide was found. Infants need arachidonic acid (ARA) for brain development, muscle building and the immune system. In 2008, the EU approved oil rich in arachidonic acid as a food ingredient. It is made with a common soil fungus, Mortierella alpina. It was classified as problem-free and non-toxic. But it was not taken into account that this fungus is often allowed to grow on soy flour. So starch, which, as I said, is an ideal nutritional basis for the bacterium Bacillus cereus.
In December 2025, Nestlé reported possible contamination of its baby food with cereulide.Image: KEYSTONE
A lot of time passed since its development in the 1990s and approval in 2008 until the risk was now discovered. “Nobody looked closely,” says Lars Fieseler from the ZHAW Wädenswil. According to the food microbiologist, this indicates that contamination of arachidonic acid has not yet occurred. Otherwise, many infants would have become sick or even died, which would not have gone unnoticed.
Expert: “This mix is not a Betty Bossy recipe”
In individual cases, especially with babies born prematurely, things look different: “Within a week after birth, their microbiome grows from zero to a billion bacteria per cubic centimeter of stool in the intestine,” says breast milk expert Hennet, “it is important that these are healthy bacteria.” Bacteria that promote inflammation can destroy parts of the intestines of infants – breast milk protects against this. That’s why donated breast milk is now given to premature babies or sick infants if the mother is unable to breastfeed. The milk from the first few days, colostrum, is full of important antibodies. “This mix,” says Hennet, “is not like a Betty Bossy recipe, but rather individual from mother to mother.”
A few weeks later, however, the magic formula of baby food may not be as important as it is often made out to be. At least for healthy children who grow up in the Western world under good hygiene conditions. “Breast milk is an additional protection for the immune system, but it is not super critical in this country,” says Hennet, who is otherwise a big advocate of breastfeeding. “Nature has various back-up systems.” Soon after birth, the baby’s immune system produces antibodies itself. And by the time it is fed solid food, the microbiomes of breastfed and unbreastfed children no longer differ.
Despite the risk of toxins in the industrially produced arachidonic acid and although it is not prescribed for infant formula, the additive is no longer dispensed with: Mortierella Alpina is contained in all infant powder milk available in this country, from Aptamil, Beba, Bimbosan, Hipp and Holle. Since Hipp and Holle have suppliers other than those from China, they were not affected by the scandal.
Since last week, imports of Mortierella Alpina have only been permitted in the EU if they have been tested for cereulide. The European Food Safety Authority has set a maximum limit. Half of all shipments containing oil rich in arachidonic acid must be checked at the border. When asked, the Federal Office for Food Safety and Veterinary Affairs said that Switzerland has the same requirements. They came into force on Tuesday, March 3rd. In order to generally keep the risk of developing germs low, a bottle of baby milk should be drunk within two hours and never warmed up again. (aargauerzeitung.ch)