Produce's long journey means many ways for contamination to spread

FRESNO, Calif. -- Processed produce has a long journey from the grower to the table, increasing the number of chances for contamination -- and making it easier to spread.

For example, scallions, initially suspected as the source of an E. coli outbreak that has caused dozens to fall ill, can be grown in one place, washed and trimmed in another and shipped across country to be chopped up and repackaged by yet another processor.

"That's a lot of points along the way. There's a lot of opening and closing, a lot of handling going on," Trevor Suslow, a vegetable specialist at the University of California, Davis, said Monday. "If there is an issue with any particular product then it's more likely that more locations would get it simultaneously."

Outbreaks can be prolonged because of the extended shelf life of the produce. Green onions can be stored for up to a month at near-freezing temperatures, according to the U.S. Department of Agriculture. The storage life decreases to about a week if the scallions are chopped, which is the form preferred by many food service companies who value the efficiency of ready-to-go products.

Most don't think of fresh produce as dangerous, Suslow said. Yet the number of foodborne illness outbreaks linked to produce is second only to seafood, but each outbreak involving produce affects more people -- about 50 on average.

Last week, Taco Bell ordered the removal of green onions from its 5,800 restaurants nationwide after tests suggested the bacteria that sickened dozens of customers in the Northeast may have come from tainted scallions from a field in southern California.

Federal officials said Monday that testing had failed to confirm green onions as the source.

E. coli, or Escherichia coli, is found in the feces of humans and livestock. Most E. coli infections are associated with undercooked meat. The bacteria also can be found on sprouts or leafy vegetables such as spinach.

E. coli is a common and ordinarily harmless bacteria, but certain strains can cause abdominal cramps, fever, bloody diarrhea, kidney failure, blindness, paralysis and death.

The latest outbreak comes as California growers are trying to recover from an outbreak earlier this year linked to spinach in which three people died and more than 200 fell ill. Spinach growers are working on new food safety standards, said Dave Kranz, a spokesman for the California Farm Bureau Federation.

"When something like this happens everyone goes back and checks and double-checks their process," Kranz said.

Caroline Smith DeWaal, director of food safety for the Center for Science in the Public Interest, a nonprofit watchdog group, said she believes food safety changes at farms are long overdue.

She and her group want the federal government to set regulations for growers to follow on manure, irrigation water and sanitation facilities.

"Consumers want to feel safe in consuming fresh fruits and vegetables and I think that confidence is slipping," DeWaal said.

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Associated Press writers Garance Burke in Fresno, Calif., and Alex Veiga in Los Angeles contributed to this report.