The Mexican government has shut down four firms that export scallions to the United States for failing to comply with good agricultural practices.
The announcement came Sunday night after the Food and Drug Administration named several Mexican firms that handled green onions linked to hepatitis A outbreaks in Tennessee, Georgia and Western Pennsylvania.
The Mexican government did not identify the companies.
"It's still not conclusive, the evidence that those green onions were contaminated in Mexico," said Miguel Monterrubio, spokesman for the Mexican Embassy in Washington. "However, as a precaution, the government of Mexico decided to shut down these companies."
At the same time, Mexican vegetable growers yesterday questioned why the FDA has focused on them -- and not their U.S. counterparts -- in the hunt for a source of the outbreak affecting patrons who ate at the Chi-Chi's restaurant in Beaver Valley Mall.
Farms in the United States and Mexico often rely on the same group of laborers.
The viral strains implicated here and in outbreaks in three Southern states are found on both sides of the border, said Lee Frankel, president of the Fresh Produce Association of the Americas in Nogales, Ariz.
"It appears FDA is using certain assumptions to narrow the field down as opposed to tracing things back to whomever the supplier might be," said Frankel.
FDA implicated eight Mexican firms this weekend for having handled green onions linked to the recent outbreaks. Mexican scallions have not yet been linked to a hepatitis A outbreak in September in North Carolina.
As of yesterday, the number sickened in the Chi-Chi's outbreak stood at 605, with three deaths.
The eight firms listed by FDA this weekend are actually operated by four companies, said Joe Baca, director of the office of compliance at FDA's Center for Food Safety and Applied Nutrition. The firms identified operate packing sheds in northwest Mexico, Baca said.
The United States began stopping shipments from all of the firms at the border this weekend. There is no test for hepatitis A virus that can be reasonably performed at the border, Baca said, so importers have been given the option of destroying the scallions or returning them.
No source of contamination has been determined, Baca said.
"There's a possibility that the onions were exposed to water that contained the virus, or ... you had workers in the field that were suffering symptoms of hepatitis A," he said. "These onions require a lot of handling."
A third possibility is that ice used in shipping scallions could have been contaminated, Baca said.
Mexican officials inspected the firms last week, he said, and they plan another inspection. That will be followed by visits from FDA officials, said Monterrubio, the embassy spokesman.
FDA has not released information about its tracing of green onions got growers to distributors to the Beaver County Chi-Chi's. Pennsylvania Department of Agriculture officials have said Chi-Chi's scallions passed through distributors in Salinas, Calif., Arlington, Texas, and Newport, Ky.
The food distribution system is complicated making it difficult to re-trace, said Kathy Means, spokeswoman for the Produce Marketing Association, an international trade association of produce companies. But the information released by FDA should ease concerns in the general public about all green onions, she said.
"It's unfair to blame everyone else because one or more companies made a mistake," Means said. "They should be held accountable, but the entire produce industry should not be held hostage."
Monterrubio noted that while the government has shut down four exporters of Mexican green onions, another 22 remain in business.