Tomatoes and Salmonella: What to Look Out For

Over the weekend, the FDA issued a warning to consumers to abstain from certain types of tomatoes due to an outbreak of salmonellosis, an infection caused by the bacterium Salmonella. Since April, there have been 167 reported cases of salmonellosis nationwide caused by Salmonella Saintpaul, an uncommon form of salmonella. No deaths have been reported.

Given the current salmonella outbreak, is it still safe to eat tomatoes?

Yes, but only certain types. The FDA is currently tracking the source of the tomato-borne salmonella infections, but the agency has declared that cherry tomatoes, grape tomatoes and tomatoes sold on the vine are safe.

So what types of tomatoes are not safe?

Large round tomatoes (sometimes called beefsteaks) and the egg-shaped ones, (called plum tomatoes or Roma tomatoes) that are traditionally used to make sauce.

What should I do with tomatoes I already have?

If they are of the unsafe type (see above), do not eat them. The market where you bought them might refund your money; otherwise throw them out.

What if I plan to cook with them?

The FDA does not recommend cooking tomatoes to prevent illness from this outbreak; the types of tomatoes implicated in this outbreak should not be eaten period.

Why are certain varieties safe? Is there something about their genetic makeup that makes them resistant?

No. It all has to do with where the tomato was grown. Certain states and countries specialize in specific types of tomatoes. Until the FDA can pinpoint exactly where the infection occurred, it is advising consumers to avoid the types of tomatoes that are grown in the areas that have not been ruled out.

So where are the contaminated tomatoes from?

For now, the FDA has issued a list of places whose tomatoes are safe for consumption. The list includes 19 states, including California and New York, and seven countries including the Netherlands, Israel and Canada. Conspicuously absent from the list are two major sources of tomatoes, Florida and Mexico.

What about local farm tomatoes?

There is no reason to avoid tomatoes grown locally, but since the local tomato season is still at least a month away, a local farm stand selling tomatoes probably got them from elsewhere. Check to see that it wasn’t Florida or Mexico. There is no cause to worry about a farm stand selling its own hydroponically grown tomatoes.

How would a tomato get infected with salmonella?

Salmonella is a type of bacterium that lives in the intestinal tracts of humans and animals and is transmitted, initially, through contact with feces. You can understand why chicken might become infected — it’s hard to keep birds from interacting with their own excrement — but a little harder to see how a tomato would become a victim. The culprit is usually water: Crops come into contact with water when they are irrigated, fertilized, washed and processed. If that water came into contact with infected animal feces — not hard to imagine if livestock is being raised nearby — it can pass salmonella onto the crops.

Does salmonella have anything to do with salmon?

No. The bacterium Salmonella enterica var. Choleraesius, which causes hog cholera, was discovered in the late 19th century by an American veterinary pathologist named Daniel Elmer Salmon and his colleague Theobald Smith. Thereafter the entire genus was named salmonella.