The germ bomb lurking in your kitchen

Tea towels used when cooking can be seriously contaminated. Photo: Getty

Surprise! It's not your sink faucet or doorknob (though they're gross, too).

It's your hand towel, and it's teeming with major germs that could make you sick - like, salmonella-sick. That's what food safety researchers at Kansas State University found when they watched videos of people prepping recipes in a test kitchen. In their findings, published in the journal Food Protection Trends, the tool we associate with cleaning quickly became a leading cause of dangerous cross-contamination.

The videos showed people handling kitchen towels with dirty hands and after splash-and-dash washing jobs, and also drying well-cleaned hands with the same contaminated towels. People also checked their phones while cooking, likely transferring germs from everywhere they've been, including the bathroom (where microorganisms such as norovirus and E. coli commonly dwell), to the towel and ultimately, their food.

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“Probably the most surprising things we saw were lack of hand washing and how people consistently overhandled towels - even wiping the counter with them,” says lead study author Jeannie Sneed, Kansas State University food safety specialist. “Towels were the most contaminated of all the contact surfaces we tested.”

In the study, funded by the USDA Food Safety and Inspection Service, three groups of participants prepared recipes - using raw ground beef or chicken and a ready-to-eat fruit salad - in a test kitchen. To track the spread of bacteria, the researchers coated the raw meat with Lactobacillus casei, a harmless microorganism often found in yogurt but not in meat.

“Coating the meat allowed us to trace the microorganism through the kitchen,” Sneed explains. “By doing this, we could identify which surfaces became contaminated.” After the meal prep, more than 90% of the fruit salads that participants prepped alongside the meat dish showed traces of L. casei. Previous research has found that salmonella - the bacteria found in raw meat and poultry that may cause deadly food-borne illness - can grow on cloths overnight, even after they were washed and rinsed in the sink.

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While the USDA doesn't recommend using sponges because of how well their wet environment supports microbial growth, towels are still fine - if you use them thoughtfully. “I would recommend frequent washing of kitchen towels, but the frequency depends a little on how they are used,” Sneed explains. “If you use them while preparing raw meat, consider changing them at the end of the day. If you are only reheating foods, they may not be exposed to microorganisms.”

Ultimately, the best advice may just be to keep your hands clean. “Meticulous hand washing - with warm, soapy water with rubbing for 15-20 seconds - would definitely decrease the possibility of contaminating the towels,” Sneed says. The Academy of Nutrition and Dietetics estimates that proper hand washing could halve the cases of food-borne illness.

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Sneed's golden rules for safe handling of kitchen towels:
1. Thoroughly wash your hands - with soap and warm water - both before meal prep and after handling fresh produce or raw foods such as meat or eggs.

2. Don't use the same towel for every task. Have different towels for different purposes (drying hands, drying dishes, cleaning). Sneed designates certain cloth towels as being only for drying clean hands. She also doesn't shy away from using the odd paper towel, especially to wipe down counters (and she doesn't re-use them).

3. Drop those dirty rags in the washing machine daily or right after using them to prep raw foods such as meat or eggs.

4. Separate ready-to-eat foods, such as fresh fruits and vegetables, from raw meat and poultry to avoid cross-contamination. Sneed color-codes her cutting boards for each purpose.

5. Resist checking your phone or tablet while preparing food, or if you must click and swipe, wash your hands afterward and wipe down food-prep surfaces with a disinfectant solution.