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 can 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 David Acheson, chief medical officer with the FDA's Center for Food Safety and Applied Nutrition. He said small amounts of the food were eaten, but the babies exhibited no symptoms.

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

The FBI and Orange County district attorney's office were investigating the discoveries, on June 16 and May 31, as cases of food tampering and were testing other baby food from the store where both jars were purchased. In Washington, two federal law enforcement officials speaking on the condition of anonymity because of agency policy said there was no evidence of widespread ricin contamination of baby food.

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.

The FBI still is trying to determine how ricin, which can be fatal if swallowed, inhaled or injected, turned up in a U.S. Senate mailroom.

Also unsolved is the case of two letters found last year in postal facilities that contained ricin and were signed by "Fallen Angel," who objected to new government rules for long-haul truckers.