On the path from farm-to-fork, there are many ways that foods can pick up nasty germs like the E. coli bug sickening more than 1,600 people across Europe. But there are steps consumers can take to avoid getting infected.
Health officials haven't pinpointed the source of the food poisoning outbreak that has hit Germany the hardest, but they're focusing on lettuce, tomatoes and cucumbers.
E. coli lives in the guts of people and animals and ends up in fecal matter. Those germs can end up in the water that irrigates fields or is used to wash just-picked crops. Or it winds up on the equipment used to harvest and pack up produce, said Jeffrey T. LeJeune of Ohio State University's Ohio Agricultural Research and Development Center in Wooster.
Other sources are animal waste used as fertilizer or from wildlife in the fields. And people are also a major source of contamination, said LeJeune, a veterinarian who has studied E. coli.
"And not just the chef at the greasy spoon who doesn't wash his hands," said LeJeune. "It can happen anywhere along the chain."
Many large farms avoid using manure because of the risk, he said. Manure is typically treated and dried before it is applied to a field, but "there's nobody standing over a farmer's shoulder all the time."
Organic farmers tend to use more manure and natural fertilizers than non-organic producers. Hilde Kruse, a food safety expert at the World Health Organization, said organic food producers were under the same obligations as any other farmers to ensure their practices meet proper hygiene standards.
"It's very difficult to guarantee that compost is sterile and if you can't do that, you are essentially spreading contaminated feces on food intended for human consumption" said Dr. Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota.
The European outbreak, which involves a super-toxic E. coli bug, was initially linked to organic cucumbers from Spain, but tests didn't back that up. Based on what patients said they ate before getting sick, health investigators are still focused on cucumbers, tomatoes and lettuce. Greens like lettuce and spinach make it easy for bacteria to hide within leafy folds.
LeJeune says washing fruits and vegetables helps remove E. coli but "you're not going to get rid of it all." He suggests removing "hot spots" _ damaged or dead parts like the brown edges on lettuce.
Other advice: Wash your hands before preparing or eating food _ especially after using the bathroom or changing a diaper; keep raw meat separate from other foods; and thoroughly cook food.
He also recommends just making better food choices _ skipping things like an undercooked hamburger or unpasteurized apple juice to avoid getting sick.
AP Medical Writer Maria Cheng in London contributed to this report.