Atlanta ? A salmonella outbreak potentially linked to produce has sickened at least 172 people in 18 states, health officials said Monday.

Health officials think the bacteria may have spread through some form of produce; the list of suspects includes lettuce and tomatoes. But the illnesses have not been tied to any specific product, chain, restaurants or supermarkets.

No one has died in the outbreak, which stems from a common form of salmonella bacteria. Eleven people have been hospitalized, health officials said.

Outbreaks of food-borne illness have repeatedly made headlines this year. Certain brands of packaged spinach, lettuce, carrot juice, beef and unpasteurized milk recently were recalled after they were found to be tainted with illness-causing bacteria. The most serious outbreak, first reported in September, involved spinach tainted with E. coli bacteria that killed three people and sickened more than 200.

The CDC detected the salmonella outbreak two weeks ago through a national computer lab system that looks for patterns and matches in reports of food-borne illness. The U.S. Food and Drug Administration has joined the investigation and will try to help trace the outbreak to its origin.

The states involved are Arkansas, Connecticut, Georgia, Indiana, Kentucky, Maine, Massachusetts, Michigan, Minnesota, North Carolina, New Hampshire, Ohio, Pennsylvania, Rhode Island, Tennessee, Virginia, Vermont and Wisconsin.

Fifty-one cases reported in Massachusetts in September are the same strain as that in the national outbreak, said Donna Rheaume, a spokeswoman for the Department of Public Health. It was not immediately clear whether those cases were in addition to the 172 reported nationwide.

Salmonella generally cause a nonfatal, diarrhea-causing illness. Other symptoms can include nausea, vomiting, abdominal cramps, fever and headache.