Have you opened some frozen food to find it has a dry, grayish surface or lots of ice crystals clinging to the surface? This is freezer burn. Freezer burn is simply the result of air coming into contact with food, and while it may not look appetizing, it is usually safe to eat.
The phenomenon of freezer burn happens when tiny ice crystals on the food’s surface evaporate directly into vapor without first going through the liquid water phase – a process scientifically termed sublimation. This moisture loss or dehydration leaves the food’s surface layers dried out and discolored.
Freezer burn happens when food is not adequately wrapped to remove oxygen, which has a bleaching effect on the food surface. Food stored constantly at 0 °F will always be safe. Only the quality suffers with lengthy or inadequate freezer storage.
The bleaching and moisture loss effect of freezer burn may not make food unsafe to eat, but it certainly affects the taste, texture, and color. Severely freezer-burned food will have an off taste and smell that is especially noticeable. It’s best to toss any food that exhibits severe freezer burn as the quality does not merit the effort to save or prepare it. Products exhibiting mild freezer burn are usually fine to eat by cutting away the burned area either before or after cooking. Foods with a higher water content are more likely to get freezer burn.
A few simple precautions will help to avoid freezer burn and ensure frozen foods remain at peak condition at time of use and eliminate food waste. Here are some tips from the experts:
- Use freezer-safe containers. Only use bags, jars, paper and containers that are labeled for freezer use. These products are designed to keep air out.
- Remove as much air as possible. Air is the enemy of frozen food. Vacuum sealers do a wonderful job of removing air. However, squeezing the contents without smashing will also remove a lot of air. Some people like to insert a straw into the corner of a zipper bag and pull air out before the final close. If using freezer containers, crumple a piece of waterproof paper on top of the food to help minimize headspace. This helps prevent freezer burn, ice crystal formation, and keeps food pieces from drying out.
- Maintain the freezer temperature at zero degrees F or lower to help freeze food fast and stay frozen solid. Foods stored near or in freezer doors or at the top of a chest freezer should be eaten first as these areas are for short-term storage. Also avoid packing the freezer tightly; air must be able to flow freely around the food.
- Let foods cool before packaging. The USDA recommends cooling food as rapidly as possible, either in the refrigerator or in an ice bath. Cold foods are less likely to trap steam inside the packaging. Steam, like air, is detrimental to frozen foods as it turns to ice crystals. Individual blanched vegetables, fruits, meat pieces, and baked goods are best if cooled and then flash frozen on baking trays (tray pack method) for an hour or two before packaging.
- Store-packaging may be left on meat products but they should be over-wrapped in freezer paper, heavy duty foil or plastic wrap, or placed in freezer bags prior to freezing for long-term storage.
- Label and date. Freezing keeps food safe almost indefinitely. However, there are recommended storage times for best quality. Refer to the FDA Refrigerator and Freezer Storage Chart which lists optimum freezing times for best quality.
Freezer burn affects food’s quality but not its safety. Even though the food is safe to eat, it doesn’t mean one should. Freezer burn fundamentally changes a food’s chemical composition, affecting its flavor and texture. All foods are susceptible to freezer burn but with proper packaging and freezer management, the problem can largely be eliminated.
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