Something I learned recently while writing about the listeria outbreak in the U.S. is that not only can listeria survive inside a refrigerator, it's one of the few bacteria that can actually continue to grow, albeit more slowly.

That means if you place a listeria-contaminated food item in your fridge, the germs can contaminate your refrigerator shelves and actually spread to your other foods. 

Listeria is killed off during the cooking process, but that’s not much help if your listeria-contaminated hotdog drips juices onto your fruit drawer. You might kill off the listeria when you cook up that hotdog, but if you grab an apple and forget to wash it, you could still find yourself with a case of listeriosis.

So how do you keep your fridge from a becoming a homemade cauldron of foodborne illness? Here are a few tips culled from the U.S. FDA and Health Canada for keeping your fridge safe:

Storing food

• Keep your refrigerator at 4 degrees Celsius or lower (40 degrees F), and the freezer at -17 Celsius or lower (0 degrees F).
• Place an appliance thermometer in the refrigerator and check the temperature periodically.  Adjust the temperature control to keep foods as cold as possible without causing them to freeze.
• Place all foods in either plastic bags, covered containers, or well-wrapped in tin foil. Make sure foods do not leak juices onto other foods.
• Eat up precooked and ready-to-eat foods as soon as you can. The longer they are stored in the refrigerator, the more chance listeria has to grow.
• Store opened packages of deli meat and meat sliced at a local deli no longer than 3 to 5 days in the refrigerator.
• Store opened packages of hotdogs no longer than 1 week
• Keep leftovers in the fridge for no more than three days. “It's better to be safe than sorry,” says Donald Zink, senior science advisor at FDA’s Center for Food Safety and Applied Nutrition.

Clean Refrigerator Regularly

• Clean up all spills in your refrigerator right away -- especially those involving hot dog and lunch meats, raw meat, and raw poultry. Use paper towels in the cleanup, to avoid transferring germs from a cloth towel or sponge.
• Clean the inside walls and shelves of your refrigerator with warm water and liquid soap, then rinse.
• As an added measure of caution, sanitize your refrigerator monthly using the same procedures described below for kitchen surfaces.

Clean Hands and Kitchen Surfaces Often

• Thoroughly wash food preparation surfaces and cutting boards with warm, soapy water after each use.
• To sanitize your counters and sinks, you can buy sanitizing products, but you can also make your own. All it takes is 1 teaspoon of bleach added to one 1 litre of water. Spray or flood the surface liberally, and let it stand for 10 minutes.  Then rinse with clean water.
• Bleach solutions get less effective with time, so discard unused portions daily.
• Dish cloths, towels and cloth grocery bags should be changed often and washed in the hot cycle of your washing machine.