US officials have warned against Roma, round and plum red tomatoes
Supermarkets and restaurants in the US have stopped selling certain types of tomatoes because of salmonella fears.
The US Food and Drug Administration (FDA) is still searching for the source of an outbreak that has affected at least 145 people in some 17 states.
The FDA has warned against eating raw plum, round or Roma red tomatoes unless they are from certain states or abroad.
McDonald's, Burger King and Taco Bell are among the chains to have stopped serving those types of tomatoes.
Cherry and grape tomatoes and those sold with the vine still attached have not been associated with the outbreak.
Home-grown tomatoes are also safe to eat raw, US officials say.
Symptoms of salmonella, which usually appear within 12 to 72 hours of eating contaminated food, include diarrhoea, nausea and vomiting, headaches, stomach cramps and fever.
The US Centers for Disease Control and Prevention said on Saturday there had been 145 reported cases - all caused by the same unusual type of the bacteria, salmonella saintpaul - since mid-April.
The illness has struck most often in New Mexico and Texas.
At least 23 people have been treated in hospital in the present outbreak but no-one has died as a direct result of infection.
The giant US chain Wal-Mart is among a number of US supermarkets to pull the types of tomato under suspicion from its shelves.
Tomatoes that have not been associated with the outbreak come from US states that include Arkansas, California, Georgia, Hawaii, North and South Carolina, Tennessee and Texas.
The symptoms of salmonella can last for several days, but most people make a full recovery within a week.
Those most at risk of developing severe illness are the elderly, infants and people with weakened immune systems.