Just as we're heading into peak tomato season, we're faced with news of a salmonella outbreak linked to raw tomatoes. What began in mid-April as a few cases in New Mexico and Texas has now spread across 17 states. To date, 167 people have been infected with Salmonella Saintpaul (a rare strain of the bacteria) and 23 people have been hospitalized reports the Centers for Disease Control and Prevention.

Salmonella-bacteria living in the intestinal tracts of animals including humans-are transmitted when people eat food contaminated with animal feces. Those infected experience flu-like symptoms–fever, diarrhea, nausea, vomiting and abdominal pain-within 12-72 hours of consumption. Typically, the illness lasts four to seven days without requiring treatment but can be serious in children, the elderly and people with weak immune systems.

"You don't want to cut tomatoes entirely from your diet–they're low in calories, rich in cancer-fighting vitamin C and high in fiber," says Sarah Klein, spokeswoman for the food safety program at the Washington, D.C.-based Center for Science in the Public Interest. "Not all tomatoes are affected by this warning." Follow these tips and you'll get the fresh flavor without the risk.

Avoid This at the Supermarket

While the Food and Drug Administration (FDA) has not yet identified the specific source and type of contaminated tomatoes, investigators believe raw red plum, red Roma, or round red types to be the culprits. "You can't detect salmonella with the eye, so it's best to skip these varieties altogether for now," says Klein. "If the bacteria has found its way to the tomato's interior–at the stem where it was picked from the vine or through a small crack–it's not something you can scrub away."

Some 280 grocery stores nationwide have pulled the tomatoes in question from shelves and most are refunding purchases. The FDA has released this list of states shown not be the source of the outbreak, but, says Klein, this only helps if you can be certain of your tomato's origins. There is good news. You can still safely munch on juicy cherry and grape tomatoes, as well as tomatoes sold with the vine still attached and homegrown tomatoes, which have all been cleared by the FDA.

Avoid This in Restaurants

Cooked sauces and ketchup are not affected by the outbreak, says Klein, but fresh salsa, guacamole, pico de gallo and tortilla fillings often contain raw tomatoes so bypass those menu options. If you're unsure what type of tomato a restaurant serves, request that they be left off your salad or burger. Taking them off your dish when it arrives at the table won't protect you; you could still get sick from cross-contamination. A growing number of restaurants–Burger King, Chipotle Mexican Grill, McDonald's, Outback Steakhouse and Taco Bell, among others–aren't taking chances and have voluntarily removed the targeted tomatoes from their dishes.

Steps to Safe Produce Prep

About 40,000 cases of salmonella are reported every year in the U.S., and it's more common in summer, reports the CDC. Here's a list of refresher tips to help you play it safe when preparing fresh produce:

  • Discard bruised, damaged or spoiled produce
  • Wash hands with warm water and soap before and after preparing raw produce
  • Wash fruits and vegetables under running water, not in a water-filled sink
  • Use a clean knife and cutting board when slicing fruits and vegetables
  • Wash cutting board in between each type of food you prepare
  • Keep fresh produce from contacting other raw foods and surfaces they touched
  • Cook tomatoes at 145° for at least 15 seconds to kill salmonella

If you've recently eaten raw tomatoes (including dishes containing them as ingredients or condiments) and experience flu-like symptoms, contact your doctor.

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(Orginally printed Summer 2008)