A bagged salad mixture is being blamed for the sudden outbreak of cyclospora last week in at least two states, but officials are not releasing the name or brand of the salad until more research can be done.

Health officials in Iowa and Nebraska say they believe the stomach bug that affected over 300 people–and hospitalized over 20 across various states–was more than likely caused by the greens, which were a mixture of romaine and iceberg lettuces as well as cabbage and carrots. 80% of those affected reported a common use of the salad, but until further information can be gathered, officials can’t say for sure that it was the cause of the illness.

“Iowans should continue eating salads as the implicated prepackaged mix is no longer in the state’s food supply chain,” said Steven Mandernach, chief of the Food and Consumer Safety Bureau of the Iowa Department of Inspections and Appeals.

The CDC and the FDA are working together to track the source of the illness and to determine whether the bug was is part of the same outbreak in every state that reported sickness. As of now, the CDC reports that Iowa, Texas, Nebraska, Florida, Wisconsin, Illinois, New York City, Georgia, Missouri, Arkansas, Connecticut, Kansas, Minnesota, New Jersey, New York, and Ohio have all shown signs of cyclospora.