People might want to think twice before starting a veggie diet these days, as the Salmonella risk remains high all over the United States. Federal officials have warned that tomatoes carrying an uncommon type of Salmonella, known as Saintpaul, may still be on the market.

The following types of tomatoes have been associated with the outbreak: raw red plum, red Roma, round red tomatoes, and products containing these tomatoes. However, the U.S. Food and Drug Administration recommended consuming them if grown and harvested from certain areas (a complete list can be found here).

Since mid-April, a total of 810 cases of cases of Salmonella have been reported, and the number could grow if infected tomatoes are still on the market. As the outbreak reaches into its third month, health authorities advise consumers to remain cautious.

The clinical features of a Salmonella infection are diarrhea, fever, abdominal cramps, which occur 12-72 hours after the infection sets in. Left untreated, patients may deal with severe infections afterwards.

Despite the fact that some people are able to recover without treatment, others may develop severe infections, which spread to the bloodstream and other body sites, and can cause death. Seeking medical treatment is advised in all cases.

Ken Lee, director of the Ohio State University Food Safety Center, explained for The Boston Globe how tomatoes may get infected with Salmonella:

After being exposed to the sun as they come off the vine, and cooled after they have been picked up, tomatoes contract. This causes all the bacteria and dirt on the surface of the tomato to be sucked inside, which makes washing them an ineffective way of avoiding Salmonella infections.

The FDA advised consumers to limit their tomato consumption as much as possible, and be aware of not only raw tomatoes, but also of dishes that may contain tomatoes (salsa, guacamole, pico de gallo, fillings and many other dishes).

Up to this point, cases of Salmonella have been identified in 36 states and the District of Columbia, and although many of them date back to mid-May, the risk of infection is still present.

As Salmonella infections are being reported every day, health authorities are now questioning whether tomatoes are the real or only cause for the outbreak. The FDA continues to be concerned with the fact that people are still exposed to this uncommon strain of Salmonella.

Tomatoes may not the only ones responsible for the outbreak, according to Dr. David Acheson, associate commissioner at the U.S. Food and Drug Administration. Other ingredients may have contributed as well, and tests will continue until a source is identified.

The investigators are currently analyzing water and other environmental samples in order to establish what the real cause of the Salmonella outbreak may be. However, there is no guarantee that the source will ever be found.

The FDA complained that one of the many challenges standing in the way of determing a source for the outbreak is that there is no product code, no “sell by” date, no markings on the tomatoes, and that the product is hard to be traced back to the producer, since most of the times the tomatoes come from multiple sources.

No deaths have been reported so far, except for a man in his sixties from Texas suffering from cancer. Reports have shown that at the time of his death, he also had a Salmonella Saintpaul infection, which may have contributed to his death.