You're about to shovel a greasy fistful of french fries into your mouth. Stop. Where have your hands been today? Did you wash them before your drive-thru lunch? If you're like most folks, then you probably did not. People wash their hands only 30 to 50 percent as often as they should, say experts. Why so dirty? Maybe it's that we're all so on-the-go these days. Who has time for personal hygiene?

It was a relief, then, when quick-and-easy waterless "alcohol gel hand sanitizers" started appearing in stores. After all, soap and water are so old-fashioned. As the maker of the first sanitizer to hit the consumer market, Purell, likes to encourage customers, "When you can't get to soap and water, Purell Instant Hand Sanitizer is a convenient, effective way to kill germs that may cause illnesses transmitted by hands. Use it anytime, anyplace."

Anyplace indeed -- clerks in the grocery store now have a bottle of the clear gel at their stations; new parents offer gel squirts to anyone wanting to cradle their newborn -- this time-saving product has even been spotted in fast-food restaurants. Hand sanitizers seem to provide cleanliness on the fly.

Too good to be true?

Often used as a replacement for the traditional method of cleaning hands -- soap and water -- hand sanitizers are actually too good to be true. Last month Barbara Almanza, Ph.D., R.D., professor and food-service sanitation expert at Purdue University, announced that hand sanitizers "do not significantly reduce the overall amount of bacteria on the hands, and in some cases they may even increase it." Not a very reassuring thought for people who use sanitizers to avoid passing germs. If Almanza is right, we could be passing more bacteria, not less.

Almanza is critical of the public's new overdependence on hand sanitizers. "I don't think the public has a good understanding of the appropriate use of hand sanitizers," she says. "The analogy I use is how in restaurants dishes are washed in three steps: first the visible dirt is removed, then the dishes are rinsed, and then they're sanitized. If we jumped right to the sanitizers, we'd be glossing over the dirt that might be there. The same is true of hand washing."

In fact, Almanza is supported by a 1994 study on the efficacy of different soaps and instant hand sanitizers, sponsored by General Mills Restaurants, Inc. The findings are surprising, especially considering that hand sanitizers' sole claim is to kill germs. The study found that the use of sanitizers actually resulted in a significant increase in bacteria on the hands -- more than double the original amount. Purell's product increased the load of bacteria by a whopping 156.7 percent. By contrast, washing with soap and water significantly reduced the amount of bacteria on hands.

Battle of the studies

Mike Dolan, vice president of research and development for Purell, doesn't agree with the General Mills study findings or with Almanza's contention that sanitizers can increase bacteria. "Absolutely not," he insists, " ... to say that it increases microbial counts is just ludicrous." Dolan goes on to say that "the [General Mills] study has been discredited by most in the field. You can get these findings in a lab, maybe, but not in the real world."

A 1999 study performed by the U.S. Food and Drug Administration's Center for Food Safety and Applied Nutrition, however, echoes the findings of the General Mills study. FDA scientists state, "Alcohol gel sanitizers that do not require rinsing may be ineffective on their own due to the fact that there is no mechanical action to wash away bacteria. Thus the end result may be increased resident bacteria ... on the hands." The FDA study continues, "As they dry, alcohol products [in hand sanitizers] may pull resident bacteria from deeper skin layers, thus an increase in resident bacterial counts may be noticed."

"Resident" bacteria are different from the transient germs we tend to pick up on doorknobs or countertops. While the alcohol in sanitizers did kill the transient organisms, it also stripped the skin's natural layer of protective oil, thereby releasing resident bacteria from the deeper skin layers. "Generally, resident bacteria are not the type that will make us sick," Almanza emphasizes, "but the assumption is that when you have an increase in overall bacteria, the chances are better that a disease-causing strain may be present."

Despite such findings, manufacturers of alcohol-based hand sanitizers advertise their products as almost 100 percent effective at eliminating bacteria. Purell's website claims, "Purell kills 99.99% of most common germs that may cause illness. It's used on hands without soap, water or towels, leaving them feeling refreshed and soft." It is true that alcohol is effective in killing germs on contact. But according to the General Mills study, tests used to determine the germ-killing potential of gel sanitizers are done on nonporous surfaces. The 99.99 percent rating is applicable only when sanitizer gels are tested on inanimate (nonporous) surfaces, like a countertop, rather than on human hands. Even a Purell-sponsored study done last year concluded that sanitizers should be supplemented by hand washing after three to five consecutive uses.

Regarding the company's claims of 100 percent germ-killing effectiveness, Sandy Katz, vice president of the Consumer Group at Purell, is careful to recommend hand washing as well. "I want to stress that Purell should be used as part of a hand hygiene regimen when soap and water are either unavailable or inconvenient. It is a supplement to, not a replacement for, hand washing," he says.

The old fashioned way

Experts say the best method for getting hands really clean is still warm water, soap, and friction -- for at least 20 seconds. And for times when you just can't get to a sink -- such as during camping trips or picnics -- Almanza recommends taking a pump thermos along. "If you know you'll be away from a sink, one alternative is a pump thermos with warm water," she says. "The flowing water effect is very important. Just sloshing your hands around in a tub of water is not as effective."

And if someone is in a car at the McDonald's drive-thru? "Get out of the car and use the rest room!" Almanza asserts. Probably good advice before shoveling in the fries.