U.S. Food and Drug Administration Commissioner Andrew von Eschenbach says the agency hopes to identify the source of a nationwide salmonella outbreak linked to tomatoes "in the next few days."

Speaking at the Commonwealth Club in San Francisco, von Eschenbach said Tuesday night that consumers should immediately report any signs of illness that they think might be related to eating tomatoes.

But he said it's safe for consumers to eat tomatoes grown in states such as Florida and California that investigators have determined are not responsible for the outbreak.

U.S. health officials say there have been no confirmed deaths linked to the outbreak, which has been reported in at least 17 states. More than 160 people have been sickened since April.