Sources of contamination

Hand-to-hand or hand-to-food contact. Most viruses and bacteria that cause colds, flu, and foodborne illnesses are spread this way. People with hepatitis A, noroviruses, salmonella, or the bacteria staphylococcus and streptococcus can pass these illnesses on to others by handling food.

Raw meats, poultry, and fish. These carry many harmful bacteria. One of the most serious is E. coli. This is the organism found mostly in undercooked beef, pork, and lamb. It is one of the most common causes of foodborne illness, according to the CDC. This type of bacteria causes hemolytic uremic syndrome, a serious condition that may cause kidney failure, which kills 2% to 4% of children affected. Older adults and those with weakened immune systems are also at increased risk.

Chicken, turkey, and poultry. These are linked to shigella, salmonella, clostridium, and campylobacter. These are bacteria that cause diarrhea, cramping, and fever. Meat or shellfish can be contaminated with toxoplasmosis. This is a parasitic disease dangerous to both pregnant women and unborn babies.

Seafood, particularly oysters, clams, and other shellfish. These can be contaminated with the vibrio species of bacteria that causes diarrhea or they can be contaminated with hepatitis A virus or norovirus.

Unpasteurized cheese and some meat. These can be contaminated with a strain of bacteria (Listeria monocytogenes) that can cause disease in people. It can also cause miscarriage or damage to a developing baby during pregnancy. Listeria is often found in soft cheeses such as brie. It's found more often in imported cheeses than in U.S. cheeses. Listeria is one of the few bacteria that grow well in the 40°F (4°C) temperature of a refrigerator.

Contaminated fruits and vegetables. These can carry many organisms and parasites, depending on where they were grown and how they were processed. Fresh fruits and vegetables may become contaminated with salmonella, E. coli, and listeria.

Contaminated kitchen gadgets

Items in the kitchen can be contaminated by contact with contaminated people, foods, pets, or other environmental sources.

The main way that contamination spreads in the kitchen is by our hands. Too often, people don't wash their hands before making food. And people often don't wash their hands between handling possibly contaminated foods such as meat and other foods that are less likely to be contaminated, such as vegetables. This cross-contamination is a main cause of foodborne disease.

Kitchen items that often become contaminated include:

• Can openers

• Cutting boards

• Countertops. Most people use their countertops not only for food prep, but also for possibly contaminated items such as grocery bags, mail, or household objects.

• Dishrags, towels, sponges, and scrubbers

• Garbage disposals

• Sink drains and the J-shaped pipe under the sink (called a P-trap). This holds some water to block sewer gas from seeping back up through the sink.

• Refrigerators

• Complex appliances such as food processors, blenders, and eggbeaters

Cleaning vs. disinfecting

Many people think that if something looks clean, it's safe. A kitchen can look perfectly clean. But it can be contaminated with a lot of organisms that cause diseases. Cleaning and disinfecting are two different things. Cleaning removes grease, food residues, and dirt, as well as a large number of bacteria. But cleaning may also spread other bacteria around. Disinfecting kills organisms (bacteria, viruses, and parasites).

Disinfectants and sanitizers are widely available as liquids, sprays, or wipes. Any of these will work well, killing almost all bacteria and viruses. You can also make your own inexpensive disinfectant. Just add 1 tablespoon liquid chlorine bleach to 1 gallon of water. Store the solution in a spray bottle and make a new solution every 2 to 3 days.

You should clean thoroughly before you disinfect. Food or grease buildup won't allow the disinfectant to get through.

How you dry your dishes and utensils also plays an important role in kitchen sanitation. From least effective to most effective, drying processes can be ranked:

• Drying with a dishtowel (least effective)

• Drying with a paper towel

• Air drying

• Drying in the dishwasher

• Sterilizing cycle in dishwasher, if available (most effective)

Cleaning hands and disinfecting the gadgets

Always wash your hands before eating, before making food, and after cleaning up the food prep area.

Outside the kitchen, you should wash your hands:

• After using the bathroom

• After handling pets or cleaning up after them

• After caring for another sick person

• After blowing your nose, coughing, or sneezing

• Any time that you think your hands might be contaminated

To wash your hands, use soap and water. Always clean the palms, the top surfaces, between the fingers, and up the wrists. Short fingernails help maintain cleanliness.

According to the CDC, plain soap works the best. Studies have shown that there is no added benefit in using antibacterial soaps and cleaners. They may be linked to antibiotic-resistant infections. Alcohol-based antibacterial hand sanitizers can come in handy when there is no water for washing. But they don't work against all viruses, including norovirus. Follow this method for good handwashing:

• Use soap and warm running water.

• Lather your hands well.

• Wash all surfaces, including between your fingers, the palms and backs of your hands, wrists, and under your fingernails.

• Wash thoroughly for 20 seconds. (Ask your children to say their ABCs while they wash—that way they'll spend enough time washing.)

• Rinse well.

• Make this a habit, especially before meals and after using the bathroom, whether you're sick or not.

If soap and water are not available, an alcohol-based hand sanitizer that contains at least 60% alcohol can be used to clean your hands. When using these products:

• Apply the gel to the palm of one hand.

• Rub your hands together.

• Rub the product over all surfaces of your hands and fingers until they are dry.

Here are some tips to prevent infections from kitchen gadgets:

• Can openers, handheld and electric. Clean after each use. After cleaning, wipe with your bleach solution (or commercial disinfectant). Let air dry.

• Cutting boards. If practical, keep two cutting boards. Use one for meat and one for fruits and vegetables. Clean after each use. The meat cutting board should be sprayed or wiped with your bleach solution and allowed to air dry. Rinse the board in clear water before the next use. This helps remove the remaining bleach taste from the board.

• Countertops. Clean them well. Then spray or wipe with bleach solution. Allow to air dry. If there is a remaining "frost" from the bleach, it may be wiped off with a clean cloth.

• Dishrags, towels, sponges, and scrubbers. These are often highly contaminated. You shouldn't use a sponge in the kitchen. Use a clean dishcloth daily. After use, rinse thoroughly and air dry. If you use the dishcloth for wiping the floor or wiping up after pets or any general cleaning, put it in the laundry and get a clean one. Scrubbers (metal or plastic) should be washed in the dishwasher each time you run it. If you don't have a dishwasher, rinse them well to remove any visible food residue. Then soak them in your bleach solution for 10 minutes.

• Garbage disposals. The film that builds up on the inside of the disposal is filled with bacteria. Use a long-handled angled brush and a chlorinated cleansing powder to scrub the inside walls of the disposal and the underside of the rubber splash guard. Let the cleanser remain in place (don't rinse) until the next time the disposal is used. This gives the chlorinated disinfectant time to kill the bacteria. This should be done at least once a month. Make sure the disposal is off and can't be turned on during this procedure.

• Sink drains and P-trap. Before going to bed, pour 1 cup of hot water into the drain. Wait a minute for the drain to soak up heat from the water. Then pour in 1 cup of chlorine bleach (undiluted). Let this stand overnight. This should be done every 1 to 2 weeks. This will help sanitize the drain and keep odors down. But it will also help keep the drain running freely.

• Refrigerators. The fridge should be cleaned thoroughly from time to time. After cleaning, it should be wiped with your bleach solution. Then the food should be put back in. Spills should be cleaned up right away. Don't let food get moldy or decay in the fridge. If you have a recalled food item in your refrigerator, it's important to throw out the food and clean your refrigerator.

• Complex appliances, such as food processors, blenders, and eggbeaters. The dishwasher is the best way to clean these items. First, check the items well and remove any bits of food. Then put the washable parts of these items in the dishwasher.