Inspectors are collecting soil, water and produce samples, reviewing export logs and combing packing plants in three major tomato-growing states in Mexico.
But the U.S. Food and Drug Administration appears no closer to finding the source of a mysterious salmonella outbreak that has sickened more than 940 people nationwide. It's not even 100 percent sure that tomatoes are the cause.
A team of three FDA inspectors has gone through five farms in the western states of Jalisco and Sinaloa in the past two weeks, looking at all aspects of tomato production: greenhouses, packing plants and shipping methods for the trip north to the U.S.
They also plan to visit the northern state of Coahuila to finish their study.
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The results can't come too soon for the three Mexican states that were targeted by the FDA, along with farms in Texas and Florida.
Bonanza 2001 farm in Autlan, Jalisco, which normally exports about 12,000 tons of tomatoes a year to the U.S., has hundreds of tons sitting in a warehouse, said spokesman Luis Almejo.
The outbreak, which began in April in the U.S., has affected people in 40 U.S. states, more of a third of them in Texas, according to the Centers for Disease Control and Prevention. There have been 225 cases reported since June 1 – evidence that the source likely has not been contained.