11 Freezer Storage Mistakes That Are Ruining Your Frozen Food

Avoid these common food storage blunders.

The freezer might very well be a home cook's best friend. It allows you to preserve food for later use, whether you're stashing away delicious leftovers or storing an abundance of summer berries. And you can stock your freezer with frozen ingredients from the supermarket, making it convenient to whip up quick meals throughout the week.

But the freezer is only as efficient as you make it. To ensure you're getting the most out of this handy appliance—while also reducing the risk of foodborne illness and food waste—think about your freezer habits. We've compiled the 11 most common freezer mistakes, according to experts. Learn how they can negatively affect your food, plus what you can do to correct them.

Meet Our Expert

• Mitzi Baum, MSc, food safety instructor at Michigan State University and CEO of STOP Foodborne Illness

• Bryan Quoc Le, Ph.D., food scientist, food consultant, and author of 150 Food Science Questions Answered

• Jay Weinstein, chef instructor of plant-based culinary arts at the Institute of Culinary Education

Related: 6 Common Food Storage Mistakes to Avoid, According to Food Scientists

Not Checking or Correcting Your Freezer's Temperature

If your freezer is not set to the correct temperature of 0 degrees Fahrenheit, frozen foods can thaw, giving harmful bacteria an opportunity to grow, says Mitzi Baum, MSc, food safety instructor at Michigan State University and CEO of STOP Foodborne Illness. Eventually, they can multiply to large amounts, potentially causing foodborne illness once consumed. This is especially likely "if the foods are thawed improperly and not cooked to the appropriate temperature to kill bacteria," says Baum.

The fix: Check your freezer's temperature and set it to 0 degrees, which will inactivate microorganisms, including bacteria, yeast, and mold.

Freezing Hot Food Right Away

After you cook food, it can be tempting to stash it in the freezer straight away to save time, but it's not the best move. Putting hot food in the freezer can raise the temperature inside the box, prompting other foods to start thawing, says Baum. This will encourage harmful bacteria to multiply and grow, increasing the risk of foodborne illness and freezer burn.

The fix: Hot food must be cooled properly before freezing, says Baum. The best practice is to separate the food into shallow containers and then cool it in the refrigerator. The smaller portions will allow the food to rapidly cool and move through the temperature danger zone (40 to 140 degrees Fahrenheit), or the range in which bacteria multiply most quickly, according to Baum.

Freezing Vegetables With High Water Content

Avoid freezing vegetables that contain high levels of water (such as cucumber, zucchini, lettuce, and fresh tomatoes) when you want to maintain their crispy texture. "Foods with high water contents form ice crystals very easily, which expand and damage the tissues of the food material," says Bryan Quoc Le, Ph.D., food scientist, food consultant, and author of 150 Food Science Questions Answered. "This causes enzymes inside the cells to be released, many of which further degrade [the tissues]." Once the vegetables thaw, the ice crystals will melt and leak through the cells, carrying away flavorful juices and leaving behind a soggy mess, says Jay Weinstein, chef instructor of plant-based culinary arts of the Institute of Culinary Education.

The fix: If you want to preserve the crispiness of raw, high-moisture vegetables, skip the freezer and refrigerate them instead. But if you've already made this freezer mistake, don't be so quick to toss out the mushy produce or its juices. Both components will "still give nutrition and dimension to purees and stews," says Weinstein. For example, thawed frozen raw tomatoes aren't good for a salad but can be used to make an excellent tomato sauce.

Not Quick-Freezing Individual Food Items

When freezing individual items like balls of cookie dough or berries, take the time to freeze them separately before putting them in a freezer-safe container or bag. Small foods will stick together when they're frozen, as moisture can transfer from one surface and recrystallize onto another, according to Le. This creates what experts call "strong ice bridges," a big hard lump of the items all frozen together, making them difficult to separate, whether you're trying to bake cookies or measure frozen berries for a smoothie. Freezing such items individually first will lock their moisture in place, says Le, ensuring they freeze without sticking.

The fix: Individually quick-freeze foods by separating them onto a baking sheet or pan and freezing until solid. Then pack them for longer freezer storage, says Weinstein.

Overfilling the Freezer

"If your freezer is too full, [it] can slow down the cooling process," says Le. That's because heat has to transfer through the frozen material, which can act as an insulator. The slower cooling process can promote the risk of textural changes, as water crystals in food can grow and break the cell walls of food, explains Le.

The fix: Store enough food in your freezer so it's about 75 percent full.

Underfilling Your Freezer

It's equally important to avoid underfilling your freezer. If your freezer is too empty, it will fill with warm external air every time you open the door, says Weinstein. This "makes the compressor work harder to re-chill the box, taking more time to freeze," he says. However, when packed with just enough food, the freezer will retain a steady, low temperature without significant fluctuations, says Weinstein.

The fix: Again, keep your freezer about 75 percent full. Avoid pressing non-frozen items against frozen ones, as this will raise the temperature of the latter, compromising their shelf-life. "Leave a half-inch of space [between food] and cool items before freezing," says Weinstein.

Not Sealing Containers Properly

Without proper storage, items can quickly develop freezer burn—the enemy of well-preserved frozen food. It's all due to the ultra-low humidity in the freezer, which "sucks moisture from exposed food surfaces, leaving behind leathery, discolored, and desiccated product," says Weinstein. Likewise, the water in the food is no longer liquid, so it's unable to form an effective barrier against oxygen and prevent freezer burn, says Le. It's worth remembering that food with freezer burn is safe to eat, but it will have undesirable flavors and textures.

The fix: Always use freezer-safe containers with air-tight lids. When using freezer-safe bags, press out as much air as possible and avoid overfilling, as this will make it hard to seal. If appropriate, wrap food tightly in aluminum foil or freezer paper to protect the food.

Using Non-Freezer Safe Containers

Another freezer storage mistake is storing food in any old container you have on hand; some materials are not safe for very low temperatures. Specifically, "plastics that contain polyvinyl chloride, polystyrene, and polycarbonate become extremely brittle when they're frozen," says Le. "This can cause the material to shatter—especially if the food is liquid and expands—and exposes the food to excess air or plastic particles."

The fix: Only use freezer-safe bags or containers. Some vessels might have a snowflake logo on the bottom to indicate they are safe for the freezer.

Related: 9 Ingredients You Didn't Know You Could Store in Your Freezer—Including Eggs and Leftover Wine

Freezing Food Without Labeling and Dating

When properly frozen, food will be safe to eat indefinitely. But as far as quality goes, it's best to consume frozen food within a certain time frame for optimal taste and texture. The only catch? Unless you label each freezer container with the item and date, it can be difficult to remember when
it's time to use (or toss) the food. This will increase the risk of freezer burn and, ultimately, food waste.

The fix: Use freezer tape or pens with freezer-safe ink to label food containers. Write the date the food was cooked or opened and the date by which it should be eaten. The latter will depend on the type of food; for example, frozen fruit is best enjoyed within eight to 12 months, while cooked ham slices should be eaten within one to two months.

Defrosting Food at Room Temperature

Even if food has been frozen properly, it can still pose a safety hazard if it's thawed at room temperature. The practice allows bacteria to rapidly multiply, increasing the risk of severe food poisoning if the food isn't handled and cooked properly, says Baum. This can happen even if the
center of the food is frozen, as the outer layer may defrost first and enter the temperature danger zone.

The fix: Defrost food in the refrigerator, where the temperature is safe and consistent. It can take about a day for food to fully thaw. Another option is to put the frozen food in a tightly sealed plastic bag and submerge it in cold tap water. Replace the water every 30 minutes.

Opening the Freezer During a Power Outage

It can be tempting to open the freezer and check on food during a power outage, but doing so is a mistake. Opening the freezer door will release cold air, ultimately lowering the internal temperature of the freezer, says Baum. This can trigger thawing, thereby speeding up the process of food
spoilage.

The fix: "Always keep the freezer closed during a power outage," says Baum.

Read the original article on Martha Stewart.