Irvine, Calif. ? Authorities found ground-up castor beans with trace amounts of the poison ricin in two jars of baby food that had been tampered with, officials said Wednesday.

U.S. Food and Drug Administration officials who tested the baby food said the ricin was not in the purified form that could be deadly. Rather, it was a less toxic, natural component of the castor beans, which can be obtained from ornamental plants.

“It’s unlikely there would be serious injury with the level of castor bean found in those two jars we tested,” said Dr. David Acheson, chief medical officer with the FDA’s Center for Food, Safety and Applied Nutrition.

Small amounts of the food were eaten, but the babies had no symptoms, he said. No arrests have been made.

The jars of Gerber Banana Yogurt also contained notes that referred to an Irvine police officer, but their exact contents were not disclosed.

Authorities called it an isolated case and said no more contamination was found at the store where the two jars were bought. “There’s no reason to believe there is any more out there,” said Dan Henson, a special agent with the FDA.

The Gerber Products Co., based in Parsippany, N.J., is working with investigators. Authorities told the company the contamination “absolutely” occurred after the food was manufactured, said Gerber spokeswoman Terry Boylan.