Roma and other large-sized tomatoes have been linked to a Salmonella outbreak that spans nine states, according to the US Centers for Disease Control and Prevention (CDC). Although the tomatoes in question have not been recalled, the CDC urges consumers to cook them instead of eating them raw.

In Texas, 21 people have become sickened with a salmonella infection since mid-April. Other states involved include Illinois, Indiana, Idaho, Utah, Colorado, Kansas, New Mexico, and Arizona. So far, no deaths have been reported in any states affected by the tainted tomatoes.

An investigation is said to be in the early stages but investigators on local, state, and federal levels are working together to identify the source of the problem and which tomatoes, specifically, are affected.

All tomatoes grown at home are still safe to eat as are small, cherry-type, tomatoes and those sold with a portion of the vine attached. Before eating them, Romas and beefsteak-style tomatoes should be cooked to at least 145 degrees for no less than 15 seconds to kill off any potential salmonella bacteria that might be on them.

If salmonella infection symptoms should occur, consumers are urged to drink plenty of water, stay rested, and consult a physician. Symptoms include headache, nausea, vomiting, diarrhea, and stomach pains. Most people recover without medical intervention within about a week but the infection can be life-threatening to others. Of particular concern are the elderly and anyone of any age with impaired immune system function.