Washington (AP) The government's food safety chief says tomatoes ``aren't off the hook'' -- but the nation's record salmonella outbreak could have been caused by something else.
The government will test numerous other types of fresh produce in the hunt for the source of the salmonella, but officials aren't saying exactly which vegetables they're tracking.
The only hint: items served with fresh tomatoes. Doctor David Acheson with the FDA says being more specific without more evidence would be ``irresponsible.''
The outbreak is continuing weeks longer than food-poisoning experts had expected.
Disease detectives are exploring whether tomatoes and other produce are sharing a common packing or shipping site where both might become contaminated, or whether multiple foods might be tainted while being grown on adjoining farms or with common water sources.