The U.S. Food and Drug Administration said Friday it found no evidence that Jolly Time microwave popcorn had been contaminated or tampered with, despite claims from consumers in four states who said they got sick after eating the snack.

The FDA said it began testing samples of the product, made by the American Pop Corn Co., in Sioux City, Iowa, after three people in New Hampshire became ill April 26.Since then, dozens of others in Maine, New Hampshire, Vermont and upstate New York have reported coming down with diarrhea, nausea and cramps after eating Jolly Time Butter Flavored Microwave Popcorn.

The FDA's Boston office said samples had been tested by three of the agency's laboratories for "pesticides, rodenticides, heavy metals, toxins, spoilage and tampering," but said no evidence of any contamination was found.

The FDA said the federal Centers for Disease Control had assisted in the testing, but did not elaborate.

Federal inspectors also examined the plant's Chicago packaging center and found no problems, the FDA said.

Similar tests have been conducted by state health officials in New Hampshire and New York, who also reported earlier this week there no evidence to explain the reports of illness.

Susan Epstein, acting director of the New Hampshire Public Health Services Division, said the agency had received a small number of reports of people suffering gastrointestinal problems after eating other kinds of popcorn, suggesting the symptoms may not have a common cause.

After the first outbreak, officials warned consumers against eating Jolly Time popcorn with lot numbers 11003-B or 11013-A.