At least 89 people have complained of illness to the U.S. Food and Drug Administration following the market withdrawal and eventual recall of Chobani yogurt due to a mold that caused cups to bloat and sour before their expiration date. The complainants reported becoming ill after eating the recalled yogurt. Some have called or written into Food Safety News describing episodes of vomiting and nausea after eating yogurt that appeared “fizzy” or “carbonated.” One caller reported having a “very upset stomach” and that they “couldn’t keep anything down” for several days. But as the allegations of illness file in, experts have begun looking into whether the mold, Mucor circinelloides, could be the source of foodborne illness. The early analysis says it’s not. Food safety experts contacted by Food Safety News on Tuesday largely said they did not know of any historical evidence describing the mold as a foodborne pathogen, but they were not experts on the topic and declined further comment. The mold does not produce a toxin that would cause a vomiting response, according to Cornell University food science professor Randy Worobo, Ph.D., who spoke about the mold with the Huffington Post. It’s far too early to say whether the yogurt actually caused any illnesses, Worobo said. It is not clear if any of the 89 complaints reported by the FDA have involved tests for any known foodborne pathogens. Proving a connection between a certain food product and an illness is often problematic unless the sickened individual provides a stool sample that can be tested for pathogens and those same pathogens are found in samples of the suspected food, said food safety attorney Bill Marler. (His law firm, Marler Clark, underwrites Food Safety News.) Knowing the exact pathogen sickening a patient can help give clues as to what food source might have sickened them. “Lots of things can make you ill, and without knowing the bacteria or virus that made you sick, it’s difficult to pinpoint the food source because the incubation period could be days or weeks depending on the pathogen,” Marler said. Even though the reported illnesses were not likely caused by the mold, Worobo suggested it might be possible that the yogurt contained another foodborne pathogen responsible for sickening those who reported illness. Or, he said, the sour, fizzy yogurt could just be causing a gag reflex.