STEVE INSKEEP, host:
And let's continue now with our regular report on your health. Today we'll focus on the health effects of cleaning your food. You could try those expensive veggie washes or you can just rub the apple on your sleeve to clean it off. We've spoken to scientists who've tested these methods.
And NPR's Allison Aubrey reports.
ALLISON AUBREY: The editors of Cook's Illustrated, a serious foodie magazine, like to focus on the technique of cooking. And recently editor Jack Bishop took up a matter that's been on lots of people's minds lately.
Mr. JACK BISHOP (Senior Editor, Cook's Illustrated): We wondered ourselves about what's the best way to be, you know, washing an apple, or the best way to be washing a pear.
AUBREY: To answer this the magazine did some comparative testing. They cleaned apples and pears in four different ways. They washed them with an antibacterial soap; that, by the way, is not recommended by food safety experts. They also tried washing with a vinegar solution, rinsing with water only, and scrubbing with a brush. To measure how well each technique worked, they swabbed the outside of the fruit with sterile Q-tips, then rubbed the little bits of grime onto Petri dishes.
Mr. BISHOP: And then let those go at 80 degrees for several days to sort of see how the bacteria would grow or not, and then actually physically counted the bacterial colonies that were present.
AUBREY: It turns out the scrub brush removed 85 percent of the bacteria more than the water alone. But the technique that worked the best was the vinegar solution. It removed 98 percent of the bacteria, and Bishop says it's easy to do.
Mr. BISHOP: I've got a bottle filled with three cups of cold water and one cup of distilled white vinegar. And it's in a spray bottle - the kind you might mist your plants with.
(Soundbite of spraying)
AUBREY: Bishop sprays the apple with about six squirts of the solution - just enough to coat the surface - and then rinses it under the tap.
Mr. BISHOP: The cold water will obviously wash away any residual flavor from the vinegar and finishes the cleaning process.
AUBREY: So it's really less than a 30-second investment?
Mr. BISHOP: It's a 30-second, 50-cent investment, because the vinegar is just so inexpensive. And if you put it in your pantry and you've got the bottle filled and ready to go, you don't need to do it every single time you go shopping.
AUBREY: The technique works best for smooth-skinned fruits and vegetables. When you get to broccoli, lettuce leaves, or spinach, as we've learned from recent nationwide recalls, produce is harder to clean. Bishop's team found soaking lettuce in the vinegar solution works well, though it's much more labor intensive.
Mr. BISHOP: You're going to have to separate out the leaves, and that may be where it gets to be somewhat impractical because you need a fair amount of vinegar in order to get a big enough bowl that's going to be three parts cold water and one part vinegar.
AUBREY: The folks at Cook's Illustrated are not the first to document the effectiveness of acidic washes. Researchers at the Institute of Agricultural and Environmental Sciences at Tennessee State University tested vinegar wash against plain water and a commercial product called Veggie Wash they purchased at a grocery store.
Sandria Godwin oversaw the project.
Dr. SANDRIA GODWIN (Tennessee State University): We did not really find the Veggie Wash as effective or necessary.
AUBREY: Godwin says they do get rid of most bacteria, but so does water alone when it's used to soak and rinse produce.
For vegetables such as broccoli or cauliflower that have lots of crevices, she recommends a two-minute soak, even though this contradicts the advice of government food safety experts, who are concerned about cross-contamination of bacteria.
Dr. GODWIN: So they're not recommending the soaking of foods now because that puts the bacteria in the sink itself. We still think you ought to go ahead and do the two-minute soak, and then wash your sink after you get through.
AUBREY: For people who aren't willing to go to all this trouble, what about that old technique of rubbing or polishing a piece of fruit to get the grime off? There's not much research, but Godwin did have one student look into it a little bit.
Dr. GODWIN: We lined people up in here and we had them all blow on these apple and rub them on their shirts and their lab coats to see if it was effective. And surprisingly, you know, it did something. You know, it's better than nothing, but it depended on how clean your shirt was.
AUBREY: So she does not recommend it. Here's a better tip. Since bacteria and dirt are usually trapped at the blossom and stem ends of fruit, the Tennessee researchers say slice both ends off before eating.
Allison Aubrey, NPR News.
INSKEEP: You can get some more tips on what to do to avoid food-borne illness at npr.org/yourhealth.