March 18, 2004 -- Germs are part of my life, what I do every day at work. I've been a microbiologist for more than thirty-some-odd years. And I think it's important for individuals to understand that 80 percent of all infectious disease is contracted by contacting or touching.

It is the interface of individuals, one with another, and their environment, that causes infection. I'm not a believer in living in a bubble. But I am a believer in cutting down on the unnecessary infections. People don't realize that in the home, 50 percent to 80 percent of food-borne illnesses are contracted by items that are handled in the home. And 60 percent to 65 percent of all colds are contracted in the home.

Wash Your Hands

Of course, the most important thing to be learned in the home is to wash your hands. In 80 percent of all infectious diseases transmitted by contact, both direct and indirect, washing your hands can become the No. 1-critical thing to do for your own protection.

People don't wash their hands. If 80 percent of all infectious disease is transmissible by contact both directly and indirectly, hand-washing is like a godsend. That's something everybody should be doing, after food prep, after contamination, before eating or drinking anything, and after using a restroom. It's common sense.

To wash hands effectively, wet your hands and lather with soap. Then rub the soapy water all over your hands and fingers, not forgetting to clean under your fingernails, for 20 or 30 seconds. Rinse, and repeat. For your health's sake, you should wash your hands several times during the course of the day. At a minimum you should do so before eating, after using a bathroom facility, and after contaminating your hands with a cough or sneeze.

Cross Contamination

An example of cross contamination is easily illustrated by using a chicken that is infected with salmonella. You cut up the chicken and wash away the remains. You use a sponge to clean up the mess. After rinsing the sponge, you may use it to clean up a countertop, or an appliance — where you apply those germs that were from the chicken to the refrigerator door or a countertop. Individuals may come in after you've cleaned and pick up the salmonella.

Clean Your Sponges

It is of paramount importance to clean your sponges properly. The solution to cross contamination is to have a small bowl containing 1 ounce of bleach in a quart of water. Whenever you are done cleaning an area, soak the sponge in the solution and let it air dry. The combination of the bleach and the dryness will kill all dangerous bacteria. Make sure to change the solution once a day.

Be Careful Not to Transmit in a Pool

Going into a pool, for example, is another way you can contract E. coli 0157. If a kid has that organism, goes into a pool that's not properly chlorinated, and other kids use it and ingest the water, that's another way. There are many germs out there that are highly dangerous. There are many others that are beneficial, and useful, and we all need germs in our everyday life.

Keep Your Toilet Lid Closed

When using the bathroom it is important to lower the seat cover before flushing. High-powered toilets can launch germs and bacteria into the air when flushed and these particles could spread throughout the bathroom, onto countertops, on your comb or toothbrush.

Besides lowering your toilet seat cover, make sure to keep your toothbrush in your medicine cabinet, because guests to your restroom may not lower the seat cover.

Sanitize Your Plunger

The bathroom can be a hot spot for bacteria and germs. For example, take the toilet cleaning brush or the plunger that people use to remove clogs. Usually there are feces present when a plunger is used to remove a clog. Many people rinse it out as the flush of water comes, and they'll take that plunger and put it right next to the toilet, for the next event.

Rinsing the plunger is not enough to kill dangerous bacteria. A good technique would be to throw some bleach in the un-clogged toilet and allow the bleach to kill the organisms on the plunger.

Bedding

A close look at your sheets can find fungi, mold, pollen, hair and skim cells. The average person sheds about 1 ½ million skin cells per hour. Human skin cells attract mites and mite feces, which are allergenic and microscopic. Changing your sheets weekly will cut down on these items being present.

An additional plan of attack should be semi-permeable covers over your mattress and pillows. This will keep the mites at a minimum. In five to 10 years, 10 percent of the weight of the pillow can be dust mite debris. If you have an impervious cover, all you have to do is use a new pillowcase once a week. Seal mattresses inside plastic or heavily woven impervious coverings.

Change Your Carpets

There is a lot of changing done in the bedroom and skin cells and hair follicles attract allergenic mites. You should not have a carpet in your bedroom. In my home, I have no wall-to-wall carpeting. I have area rugs, and mostly hard-surfaced floors. That's something that you can do, very easy to do. If you do have a rug, vacuum appropriately. This means vacuuming frequently and vigorously. Be sure vacuum is fitted with air filters that prevent allergens and dirt from being recirculated into the household air. Make sure to change the filter bag and repair any leaks.

Washing

It's not enough to separate your laundry by colors and whites. That will prevent colors from running but it will not kill bacteria. If you wash your underwear with anything else it's important to add bleach or you may be spreading fecal organisms from your underwear to other items. What will kill everything is if you increase the hot water to a germicide level. Many new machines have a germicide cycle for this reason.

Sneezing Precautions

Try sneezing into your elbow so that it gets on your clothes and not on your hands, where you will pass it on to others.

Antibiotic Resistance

Antibiotic resistance does not come as a consequence of using antibacterial products too often. These include soaps and the portable gels. Antibiotic resistance comes mainly because of inappropriate or improper use of antibiotics by physicians. Some 150 million prescriptions are written annually in this country. And 60 percent of them — that translates to 90 million prescriptions — are for antibiotics. Of those, 50 million are absolutely unnecessary or inappropriate.

Conclusion

Do not be a germophobe, be germ-aware, be prudent, and use common sense, and you'll cut down on your infections.

Advice for Children

Wash hands before eating or drinking, and after using a bathroom facility. Never use someone else's eating or drinking utensils. Wash dirty toys and objects that have touched the ground. Never eat food that has fallen on floor or ground. Practice proper cold and flu etiquette, such as covering one's mouth and nose during a sneeze or cough.

For People With Pets

When you stroke, handle, or pat your pet, avoid touching your mouth, nose, and eyes until you can wash your hands. Your turtle or lizard, for example, can carry salmonella, a leading cause of gastrointestinal disease. Make sure your pets' vaccinations are up to date. Keep pets well-groomed. Wash your hands after a cleaning a cat's litter box or using a pooper-scooper for a dog's feces.

For Food and Drink

Wash your hands often with soap and water. Wash in between preparation of different foods and after completing different stages of preparation. Cut meats and vegetables with separate knives and cutting boards, or carefully wash knife and cutting boards in between the two. [Look for plastic cutting boards with an embedded anti-bacterial substance such as triclosan. Such a product cleanses the inner surfaces of slices and fissures in the board.] Cook meats and poultry thoroughly. Assume that the outer surfaces of all fruits and vegetables are contaminated. Don't leave food sitting out at room or outdoor temperatures for an extended period of time. Reheat and serve leftovers only once. Pay attention to expiration dates. Exercise care with the communal plate. The label "organic" does not necessarily mean "safe" or "germ-free."

Dr. Philip Tierno is the director of clinical microbiology and diagnostic immunology at New York University Medical Center. His most recent book is The Secret Life of Germs.