Kitchen Safety, Part 1: Fridge & Freezer Tips

September 20, 2010

The refrigerator is one of the most important things in your kitchen when it comes to food safety.

The refrigerator is one of the most important things in your kitchen when it comes to food safety. Bacteria exist everywhere. If kept at the appropriate temperature, your refrigerator slows the growth of bacteria. Here are some tips to make sure you are refrigerating and freezing foods properly.

• Make sure the refrigerator temperature is 40 degrees Fahrenheit or below, and 0 degrees Fahrenheit or below in the freezer. Occasionally verify these temperatures using an appliance thermometer.
• Refrigerate or freeze perishables, prepared foods and leftovers within two hours.
• Never defrost or marinate food at room temperature. Use the refrigerator. You can also thaw foods in airtight packaging in cold water (change the water every 30 minutes, so the food continues to thaw). Or, thaw in the microwave if you’ll be cooking the food immediately.
• Divide large amounts of leftovers into shallow containers for quick cooling in the refrigerator.
• Don’t over-stuff the refrigerator. Cold air must circulate to keep food safe.

Freezing is one of the most convenient and least time-consuming methods of preserving foods. The extreme cold slows down the growth of microorganisms and chemical changes that affect quality or cause food to spoil. However, quality largely depends on being freezer savvy: how food was wrapped, how fast it froze, how long it is kept, the freezer’s temperature and whether the food should have been put on ice in the first place.

When freezing foods, packaging materials are important. They must be moisture- and vapor-resistant, durable, and leak proof to maintain the quality of food. When packing, leave headspace of half to one-and-a-half inches to allow for expansion. Label packages with the date the food was frozen.

Containers that are appropriate to use include: plastic freezer containers, plastic freezer-weight bags, aluminum foil, foil pans, coated freezer paper, heavy plastic wrap, and zip bags. You should not freeze in glass jars (which can break), cottage cheese or yogurt containers, bread wrappers, produce bags, or wax paper. These are generally not airtight or thick enough.

There are several factors that can compromise good food that was frozen badly. Here are some things to watch out for and prevent:
Freezer Burn: To minimize the risk of freezer burn, caused by moisture loss, don’t thaw and refreeze food numerous times. That causes food to dry out faster. If food does suffer from freezer burn, cut off the affected areas -- before or after cooking - and use the rest of the food.
Microorganisms: Growth is stopped when food is frozen, but microorganisms are not destroyed. When food is thawed, they become active again and multiply; food must be cooked to be safe.
Ice Crystals: Formation of small ice crystals is better for food. Large ice crystals tend to rupture cells and may cause a texture change.
Temperature: The storage life of foods is shortened as temperature rises. A temperature of 0 degrees or lower should be maintained to keep foods at top quality. Fluctuating temperatures result in growth in the size of ice crystals, further damaging cells and creating a mushier product.
Air: Oxygen may cause flavor and color changes if the food is improperly packaged. Many foods change color when frozen due to lack of oxygen or especially long storage. For example, red meat can turn brown but it is still safe to eat.
Enzymes: Freezing slows enzyme activity, and most food keeps when put in the freezer. In vegetables, however, enzymes must be inactivated before freezing.

Time Limits for Food Storage* 
Soups and Stews, vegetable or meat: refrigerator: 3-4 days, freezer: 2-3 months
Ham fully cooked whole: refrigerator: 7 days, freezer: 1-2 months
Ham fully cooked sliced: refrigerator: 3-4 days, freezer: 1-2 months
Fresh uncooked meat: refrigerator: 3-5 days, freezer: 6-12 months
Leftover meat: refrigerator: 3-4 days, freezer: 2-3 months
Gravy and meat broth: refrigerator: 1-2 days, freezer: 2-3 months
Fresh raw poultry: refrigerator: 1-2 days, freezer: 12 months
Cooked poultry: refrigerator: 3-4 days, freezer: 3 months
Cooked poultry with broth/gravy: refrigerator: 1-2 days, freezer: 3 months

*Source: United States Department of Agriculture