The sick ate fresh tomatoes tained by salmonella at two restaurants from the same chain, said the Los Angeles Times, quoting federal officials at the Food and Drug Administration (FDA).

But the FDA declined to name the chain or the restaurant locations, citing confidentiality. A spokesman for the agency also declined to provide the time frame for the cases or say whether the restaurants were in the same state.

The Chicago Department of Public Health identified nine people who ate at a restaurant in May and came down with salmonella, said Tim Hadac, a spokesman for the department.

None of the nine Chicago victims were hospitalized. Hadac said the department was withholding the name of the restaurant, which he said had several related restaurants in the city but was not part of a national chain.

But FDA officials stressed that the locations where the illnesses were reported were not an indication of where the contaminated tomatoes originated.

"The restaurants are not the problem. The tomatoes are what is making people sick across the country, and we don't know where they came from," FDA spokeswoman Julie Anne Zawisza wrote in an e-mail.

So far, 228 people have contracted salmonella in 23 states since mid-April, health officials said. The FDA said the "vast majority" of tomatoes produced during the outbreak were "very likely" from Florida or Mexico.

The FDA is warning consumers to avoid Roma, plum and standard round tomatoes, but the agency has declared cherry and grape tomatoes and tomatoes still attached to the vine to be safe to eat. All California-grown varieties are considered safe because the agency has cleared the state as a source of the outbreak. ¡¡