Nestlé announced a recall of some batches of baby formula during the week of Jan. 5, and on Jan. 13 the firm’s CEO, Philipp Navratil, posted a video apology on Nestlé’s website.
The recall is due to contamination by the cyclic depsipeptide cereulide and is related to the formula ingredient arachidonic acid (ARA), though the connection between the two substances is not clear. Here we try to answer some of your questions about the chemicals involved in this recall.
What is Nestlé doing and why?
Nestlé has issued an infant formula product advisory after detecting cereulide in some baby formula. Formula is being recalled in more than 50 countries around the world. In the UK, for example, batches of Nestlé’s SMA brand formula are being pulled from shelves.
What is cereulide?
Structure of cereulide.
Cereulide is a toxin made by Bacillus cereus bacteria. Cereulide’s cyclic dodecadepsipeptide structure has a high affinity for potassium ions. The toxin inserts itself into cell membranes, where it transports potassium ions, thereby disrupting mitochondria and damaging cells. There is some evidence that the toxin also binds to 5-HT3 serotonin receptors in the gut and causes nausea and vomiting. Nestlé reports that no illnesses have been confirmed in connection with its products.
“What makes it so dangerous is the toxin itself is so stable and resistant to degradation,” says T. Martin Schmeing, a biochemistry professor at McGill University who has studied the enzymes that make cereulide. “So if you have contaminated material, you could cook it, microwave it, boil it; you could use harsh cleaning products that use extreme pH to break things down; or you can use enzyme treatment like proteases to break things down, and that could kill all the bacteria that makes cereulide. But the actual cereulide will still be there. It will not be destroyed of any of these treatments.”
Nestlé connects the presence of cereulide in baby formula to a quality problem with ARA, an ingredient added to many formulas, from an unnamed supplier.
What is ARA?
Structure of arachidonic acid.
Along with docosahexaenoic acid (DHA), ARA is one of the two main long-chain polyunsaturated fatty acids that are added to baby formula to make it more like human breast milk. DHA can be extracted from fish oil or produced by algae fermentation. ARA, in contrast, is commercially made only by fermentation.
One of the pioneers in the business, the Dutch firm DSM, now DSM-Firmenich, developed a method in the 1990s for fermenting ARA from the filamentous fungus Mortierella alpina. DSM-Firmenich has told news organizations that its products are not affected by the recall. The stock price of another ARA supplier, the Chinese firm Cabio Biotech, has fallen since the recall announcement. Cabio says on its website that it is the first Chinese company to commercialize ARA. It also uses M. alpina.
How did cereulide contaminate ARA?
B. cereus contamination is common, so it’s likely that the bacteria tainted the ARA oil at some stage during its processing.
Monika Ehling-Schulz, head of the Institute of Microbiology at the University of Veterinary Medicine Vienna, has studied cereulide for 25 years and helped develop the test to detect the toxin in food. She says that it’s possible for cereulide to get into ARA if the fermentation or any other processes used to make the ARA oils has been contaminated with B. cereus or cereulide. “As both ARA and cereulide are highly lipophilic, cereulide might eventually be coextracted along with ARA,” she says, “or it is also conceivable that cereulide entered the ARA oil through a contaminated ingredient during the oil-refining process.”
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