Lunch Box Safety: What Germs are in Your Kid's Bag?

A 2011 study published in Food Protection Trends found that reusable grocery bags are seldom washed and often harbor nasty bacteria, including e.coli. Reusable lunch bags have the same potential for collecting germs.

Insulated lunch bags protect food better, says Vandana R. Sheth, RD, CDE Spokesperson for the Academy of Nutrition and Dietetics, but they're no guarantee. Read on for our tips to make sure your child's lunch bag remains as clean (and green) as possible.

Washing reusable, cloth lunch bags in either hot, soapy water or the washing machine destroys more than 99 percent of bacteria, according to Gerba's study. Moisture creates an optimal environment for pathogens, so be sure to dry lunch bags in the dryer or let them to air dry completely before folding them up to keep bacteria at bay. We've all done it, but leaving lunch bags in the car is a sure recipe for bacteria. Empty lunch boxes as soon as you get home and store them in a clean, dry place.

Bacteria has a "sweet spot" temperature where it thrives, so Katie Clark, MPH, RD, CDED recommends, "Avoid the danger zone between 40 and 140 degrees Fahrenheit." Stock up on reusable ice packs to keep cold foods cold, or freeze lunch fare such as water, juice, fruit or even yogurt. They'll stay cool and keep the other foods around them from spoiling, and thaw by lunch time. A 2011 study published in Pediatrics found that over a whopping 90 percent of preschoolers' lunch items in packed lunches were kept at an unsafe temperature, which can lead to bacteria such as e.coli multiplying at an alarming rate inside of your child's lunch box.

If you're sending your budding foodie to school with a warm soup, fill a thermos with very hot water and wait a few minutes. Drain the water, then add the hot soup to the thermos and seal—taking the time to heat up the thermos beforehand will ensure your kid is greeted with warm comfort come lunchtime. Insulate hot or cool foods away from each other to make sure neither one ends up at an unsafe temperature. If you're cooking or heating up a dish before slipping it into the lunchbox, give it a chance to cool completely before packaging it up. Once it's packed up, keep the lid off until the very last second; this prevents condensation and makes the lunch container easier for tiny fingers to pry open.

One of the biggest offenders in lunchbox safety is a liquid that leaks, resulting in nasty bacteria that multiply and contaminate other foods, according to Sheth. Drain water-laden foods, such as tofu or baby carrots, in a colander or on paper towels and then pack into a paper cup to contain the spread of moisture. Store foods separately in sealed containers, and be sure your kid knows to seal them back up before returning them to the bag.

It's critical to pass on critical food safety rules to your child now, to establish healthy eating habits. Teach your child to store her wash her hands before lunch, store her reuseable bag in a cool, dry place and always give her food a once-over before digging in. "If something looks or smells funny, don't eat it," cautions Sheth. Sometimes kids chow down on lunch leftovers after school, when food can be at dangerous temperatures. Avoid any worry by having your little one toss her leftovers immediately after eating lunch.

You're careful about the spread of germs from meat products, but fruits and veggies also carry pathogens on their surfaces and should be washed. Cut into an unwashed apple and you're bound to transfer germs to the fruit. Leave the food whole if you can, since bacteria starts to grow once it's sliced. Washed grape tomatoes, apples, grapes, baby carrots and celery are great options. If your preschooler needs smaller portions, chop it carefully and keep it chilled with a tiny ice pack or frozen water bottle.

Some super foods naturally ward off bacteria, which make them ideal choices for your little one's lunch. Garlic, onion, allspice and oregano round out the strongest antibacterial choices, while thyme, cinnamon, tarragon, cumin and lemongrass kill almost as much harmful bacteria—up to 80 percent of it. Liberally seasoning dishes—especially in warmer climates—will help keep them from spoiling before the lunch bell rings.

You've followed all the rules at home, so it's time to involve yourself at school. Remind your child to hang up his lunch box next to his backpack, instead of throwing it on the floor, and chat with teachers about pre-lunch hygiene. How often are lunch tables cleaned? The more you know, the better you'll be able to plan for a bacteria-free lunchtime.

Reusable lunch bags save money, the planet and keep your little one from harm, provided you follow strict safety rules. Keep the lunch bags clean and the food at the right temperature, and your little one will can enjoy homemade fare at school. If you're still worried, pack shelf-stable products like applesauce, granola bars, whole fruit, and peanut butter sandwiches to ensure a happy, healthy child at lunchtime.