Since April, there have been 167 reported cases of salmonellosis nationwide caused by Salmonella Saintpaul, an uncommon form of Salmonella. More than 20 hospitalizations as well as one possibly related death have been reported.

Restaurants and grocers have stopped selling many tomato products, but many consumers still have questions about the risks the produce poses, including whether cooked tomatoes are safer than raw ones.

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

Yes, but only certain types. The Food and Drug Administration is tracking the source of the tomato-borne Salmonella infections, but has declared cherry tomatoes, grape tomatoes and tomatoes sold on the vine as 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, traditionally used in sauce.

What should I do with tomatoes I already have?

If they are of the unsafe types (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 to infection?

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 grown in the areas that have not been ruled out.

So where are the contaminated tomatoes from?

That has not been pinpointed, so for now, the FDA has issued a list of places whose tomatoes are safe for consumption. The list includes 19 states, including New York, California and Florida and seven countries, including the Netherlands, Israel and Canada. Conspicuously absent from the list is one major source of tomatoes, Mexico.

How would a tomato get infected with Salmonella?

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 – Salmonella can pass to crops.

Where does the name Salmonella come from?

The genus was named after American veterinary pathologist Daniel Elmer Salmon.