The worrying 17-state salmonella outbreak recently led to the voluntary withdrawal by a large number of companies of the three tomato varieties believed to be the source of the disease.

McDonald’s, Burger King, Subway, Taco Bell, Wal-Mart, Albertsons, Smith’s and many others decided to put a hold on their clients’ consumption of red plum, red Roma and round red tomatoes until the source of the spread will be identified and safety bulletins will announce the end of the crisis.

Apparently, the recalls have caused a lot of economic damage to numerous businesses including farms, groceries, restaurants and even to places where the products were announced as safe.

So far the national food poisoning managed to sicken 167 people and all efforts have been concentrated on finding the exact source of the dangerous bacteria. At this point, several states including the United States’ top tomato producers Florida and California, have been cleared of any kind of involvement in the national food poisoning incident.

"It's narrowing down rapidly. We hope that in the next few days we'll be in a position to identify the exact source," U.S. Food and Drug Administration Commissioner Andrew von Eschenbach said during a statement in San Francisco, according to the Associated Press.

Since 1990 there have been 13 cases of tomato-associated outbreaks, with the largest one back in 2004 when more than 500 people in five states turned out to be infected.

Salmonella is a bacterium that causes several illnesses including typhoid fever, paratyphoid fever and food borne illness. It can be caught by handling reptiles such as iguanas and turtles but is generally transmitted to humans by eating foods contaminated with animal feces.