Is Washing Veggies Enough?

Here's some news that should comfort mothers everywhere: Americans are eating more leafy greens than ever. Consumption rose 9 percent between 1996 and 2005, according to a report issued this week by the Centers for Disease Control. But the bad news is that leafy-green-associated outbreaks of foodborne illnesses went up much more: 39 percent since 1996.

Researchers say they are not sure exactly why the rate of illness has increased more than consumption, but they do note that many foodborne disease outbreaks can be traced to a local food preparation source. Of course, in outbreaks that were widespread, the contamination was likely to have originated at the farm or in the processing plant. (Think of the 2006 recall of spinach due to E. coli contamination that was traced back to the farms where it was grown.)

Consumers can't exactly patrol commercial spinach fields, or the kitchens of their favorite restaurants, but they can make their at-home food preparation safer, both to prevent illness due to bacteria and to help alleviate concerns about pesticide residue. But is washing produce in tap water alone enough to make it safe, or should we be doing more?

"Washing is an important step, and it helps, but it can't guarantee elimination of contamination," says Trevor Suslow, an agriculture extension specialist at the University of California at Davis. Pathogens and bacteria can almost glue themselves onto produce and can get into wrinkles, openings or small cuts. That said, Suslow and other experts say it's far better to eat fresh fruits and vegetables, just washed at home, than to forgo them. "The benefits of a diverse diet far outweigh the very, very small risk of consuming contaminated products."

What do the food safety experts do? They wash their produce in running tap water—and eat up. For example, Al Bushway, professor of food science at the University of Maine, uses a spray nozzle on his kitchen faucet to clean lettuce and a vegetable brush to clean apples. He doesn't use chlorine washes, since they give at best a "slight" reduction in microbial load. (If you really want to use chlorine, mix a tablespoon of it with a gallon of water, then rinse it off afterward.)

To further reduce risk, the experts recommend washing not just the fruit you consume with the peel on, like apples, but also fruits and vegetables that are peelable or have inedible rinds, like bananas and melons. When you slice or handle produce, bacteria could be transferred from the peel or rind to your hands or to a knife and then to the fruit or vegetable you're eating—as could chemical residues. Washing before you peel reduces that risk. With green leafies you can take the extra step of removing the outer layer of a head of lettuce, for example, and then washing, says Michael Doyle, director of the center for food safety at the University of Georgia. "The contamination largely occurs on the outside, whether it's fruits or vegetables." Like Bushway, Doyle doesn't spend money on commercial fruit and vegetable "washes." They do a good job of removing soil and trace chemical residues, say experts, but they don't help much with bacteria.

Also, rewash bagged products, even if the packaging indicates they've been prewashed. "Anytime you do more chopping and wounding, it releases nutrients [bacteria] can grown on," says Suslow. "If you combine that with abusive temperature management, at shipping, retail or by the consumer, they will begin to multiply, and you increase your risk." Consumers need to get food into the refrigerator instead of leaving it in a hot car or trunk, he says, where bacteria can grow.

If you're truly concerned, use heat-treated canned or frozen fruits and veggies. Cooking at temperatures over 160 degrees Fahrenheit also kills bacteria, though you'll lose some vitamin C. And for those with compromised immune systems, sprouts may not be a good idea. "They're grown under optimal conditions for growing pathogens," says Doyle. "Bacteria need three things for growth: the right temperature, nutrients, water." Sprouts grow in a watery, warm environment, and the bacteria grow within them so you can't wash them away.

However you prepare your produce, remember that eating fresh fruits and veggies is one of the best paths to good health, so don't be scared away from a good salad.

For more information from the Food and Drug Administration on the best way to wash and prepare fresh fruits and vegetables, click here.