French prosecutors have opened criminal investigations into five baby formula companies: Nestle, Lactalis, Danone, Babybio, and La Marque en moins. The probes come after mass recalls due to concerns over contamination with the toxin cereulide. Eight complaints in France report infants vomiting after consuming the formula. Last week, Nestle and Danone recalled products in over 60 countries, including the UK. Officials say at least 36 infants in the UK suffered suspected food poisoning after consuming the formula. Cereulide is a toxin that resists cooking and can cause nausea, vomiting, and stomach cramps. It was linked to an ingredient called arachidonic acid (ARA) oil, which mimics some breast milk properties. The UK Food Standards Agency identified a third-party ARA supplier as the contamination source and no longer uses it. This supplier is believed to be China's Wuhan-based Cabio Biotech, which has not yet commented. China's market regulator asked domestic formula makers to test for cereulide but did not name companies. French prosecutors will determine if the formula makers are liable and are coordinating with local probes investigating the deaths of three babies in France. Nestle and France's health ministry say no evidence yet links the contamination to these deaths. So far, 28 batches from Nestle (SMA brand) and Danone (Aptamil and Cow & Gate) are recalled. Both firms say the recalled batches were made some time ago and likely are not available in UK stores, but parents should check home supplies. Nestle announced plans to run five factories nonstop in France, Spain, Germany, Switzerland, and the Netherlands to boost formula production. The Swiss company said, "We are focused on increasing the availability of infant formula to meet demand, providing parents and families with high quality products they can trust."