Grocery stores and restaurants are taking precautionary measures to protect customers from tomatoes that may be tainted with salmonella, Houston television station KPRC reported.

The H-E-B grocery chain issued a recall for fresh Roma and large, red round tomatoes following the outbreak of the Saintpaul strain of salmonella. Kroger stores posted signs in its produce departments to inform customers certain tomatoes were not available.

Twenty-one cases of salmonella have been reported in Texas, most coming from the Houston area. According to the CDC, cases were reported in Arizona, Colorado, Idaho, Illinois, Indiana, Kansas, New Mexico and Utah since April 23.

The consumption of raw Roma and large, red round tomatoes has been implicated as the likely source of infections, officials said.

Anastacio Lopez, manager of Pappas BBQ restaurant, said the restaurant would not serve tomatoes in salads on burgers and or burgers as a result of the outbreak. It also suspended serving pico de gallo until the source of the strain is confirmed.

Although their restaurant had not received an official order to stop serving tomatoes, Lopez said it wants to protect its customers.

"We're going to wait to see what the health department says," he said. "Our customers come first."

More than a dozen people have been hospitalized as a result of the outbreak, according to the Centers for Disease Control and Prevention. No deaths have been reported.

Consumers were also advised to:

Cook tomatoes to 145 degrees for at least 15 seconds to kill salmonella

Avoid buying bruised or damaged tomatoes

Throw away tomatoes that appear to be spoiled

Thoroughly wash all tomatoes under running water

Refrigerate cut, peeled or cooked tomatoes within two hours or throw them away

Separate tomatoes that will be eaten raw from any raw meat, poultry, seafood or vegetables

Wash cutting boards, dishes, utensils and countertops with hot water and soap in between handling of different foods

Wash hands thoroughly

Symptoms of salmonella infection include headache, stomach pain, diarrhea, nausea and vomiting.

Illness from salmonella normally lasts four to seven days, and most people generally recover without treatment. People with symptoms are advised to drink plenty of water, get extra rest and visit a doctor as soon as possible.

When severe infection occurs, salmonella may spread from the intestines to the bloodstream and then to other body sites and can cause death.