The probe by three inspectors from the U.S. Food and Drug Administration and one from U.S. Centers for Disease Control and Prevention – accompanied by Mexican officials – started Monday, and has not yet concluded.
U.S. officials have said they believe that green onions grown in Mexico and served in the United States were contaminated with hepatitis somewhere in the growing, packaging or delivery process.
But Baja California State Interior Secretary Bernardo Martinez that in visits to farms and packing houses in Mexicali and Ensenada – both of which are located in this state – the inspectors had not found any physical evidence of hepatitis infection.
Inspectors also visited a farm in neighboring Sonora state, and are expected to continue their inspections. U.S. officials were not immediately available for comment on the report.
However, it appears that in at least some visits, the inspection teams did not take samples of water or plant material, suggesting that testing for the physical presence of the virus may not have been among their objectives.
Martinez said some producers may decide to sue the U.S. government for damages caused by a drop-off in scallion sales following the announcement of the suspicions.
U.S. health officials have said the hepatitis strains found in Pennsylvania are very similar to those found in smaller outbreaks that occurred in Tennessee and Georgia in September. Those earlier outbreaks were traced to three companies known to have supplied Mexican green onions in those states. It is unclear whether they are the same companies currently being investigated.
Authorities are still trying to determine where along the supply chain the onions in the Pennsylvania case were contaminated. The CDC said the onions could have been contaminated with the virus a number of ways, including poor hygiene by infected workers at any stage of the onions' journey.
In the Mexicali Valley alone, there are 15,600 acres of green onions with an estimated commercial value of $44 million, according to Mexican Agriculture Department statistics.
Mexico sends nearly $3 billion in produce to the United States each year.