U.S. investigators are visiting farms in Florida and Mexico this Saturday and Sunday as they narrow their search for the source of tainted tomatoes that caused a salmonella outbreak.

The outbreak has now sickened about 552 people in 32 U.S. states and the nation's capital of Washington D.C.

Food safety inspectors are expected to visit tomato farms, warehouses and packing facilities in Florida and Mexico.

The U.S. Food and Drug Administration has identified the path of the tainted tomatoes.

Authorities say now federal investigators are retracing the route in search of the contamination source.

Food safety officials initially suspected the source originated in Florida or Mexico because they are the main suppliers of the fresh tomatoes that caused people to get sick.

Officials linked the outbreak to raw plum, Roma and round tomatoes.

Some information for this report provided by Reuters.