Many people have leftover frozen foods that have been in the freezer for a long time. Food kept constantly frozen at 0°F will always be safe to eat, but the quality will slowly deteriorate over time. Freezing prevents bacterial growth, but it doesn’t completely inactivate microbes. The maximum recommended freezer storage time for frozen foods is 3 to 12 months for best quality. However, frozen foods stored continuously at 0°F or below can safely be eaten indefinitely, though the quality and flavor will slowly diminish over time.
Does Frozen Food Go Bad?
Frozen food itself cannot really go bad in a biological sense if it remains properly frozen at 0°F or below. Foodborne bacteria and mold cannot grow in frozen temperatures, so the food will never spoil or become contaminated while frozen. However, frozen foods will undergo slow chemical changes during prolonged storage that affect taste, texture, and nutrition. Enzymes and chemicals in the food break down over time. As food deteriorates, it loses moisture, vitamins, and undergoes oxidation. The end result is poorer flavor, rancidity, freezer burn, and diminished nutritional quality. While still safe to eat, the food’s quality slowly decreases the longer it is frozen beyond the recommended storage time of 3 to 12 months.
Changes in Frozen Food Over Time
The following changes occur in frozen foods stored for prolonged periods past the recommended times:
Loss of Flavor and Texture
Frozen foods will slowly lose flavor, aroma, and texture over time. Chemical changes from enzymes and oxidation break down the quality of the food. Reactions continue to occur even at frozen temperatures, just at a much slower rate. The food’s texture may dry out or become mushy. Signs of freeze-thaw cycles, such as water crystals, make the texture seem stale.
Freezer Burn
When frozen food is exposed to air in the freezer, it loses moisture. This causes freezer burn, which dries out the product. Freezer burned spots will be dry and leathery. The food is still safe, but the texture and taste suffer. Properly wrapping or packaging frozen foods prevents freezer burn.
Loss of Nutrition
Studies show measurable vitamin and nutrient loss occurs in frozen products over time. The nutrient loss varies with the food type and length of storage time. Blanched vegetables can lose up to 50% of vitamin C content after a year. Fish can lose up to 10% of its vitamin B content after 6-8 months. The longer the food is frozen past recommended times, the fewer vitamins and nutrients it will retain.
Rancidity
Fats and oils in frozen foods can go rancid. Lipid oxidation causes unpleasant rancid flavors and odors. Foods with higher fat content are more susceptible. Signs are unpleasant bitter, cardboard, or paint-like flavors. Rancidity makes the food less appetizing but still edible. Properly packaging foods with oxygen barriers helps prevent rancidity.
Color Changes
Frozen foods can undergo color changes from prolonged freezing. Bright green vegetables may dull or yellow. Red meats turn brown. These color changes are not harmful, but foods lose visual appeal.
Safety of Eating Frozen Foods After 2 Years
While frozen foods stored continuously at 0°F are safe indefinitely, the quality deteriorates over time. Foods frozen for over 2 years past the recommended storage time will still be safe, but the quality is less than ideal. Safety risks are minimal for properly frozen foods, but quality issues are:
– Marked decline in texture, flavor, color
– Increased rancidity and freezer burn
– Substantial loss of nutrients
– Unpleasant odors, colors, textures
Hard textures become leathery and dry. Pre-cooked foods can lose appeal. The freezing process causes physical and chemical changes over time that lower frozen foods’ quality.
Most people find the flavor and texture unacceptable after 1-2 years beyond the recommended storage time. But there are no safety issues if commercially frozen foods remain frozen. Temperature fluctuations introduce more risk due to potential microbial growth during thawing periods. If properly kept at 0°F or below, frozen foods are safe beyond 2 years, but they will just taste stale.
Can You Refreeze Thawed Frozen Foods After 2 Years?
Previously frozen foods that thaw in the refrigerator are safe to refreeze provided they still contain ice crystals or are at 40°F or below. However, foods thawed for more than 2 days in the fridge should be discarded.
Thawed foods that were frozen for over 2 years beyond the recommended storage time should also be discarded, even if they were properly refrozen before thawing completely. The quality of the food already will have deteriorated. Refreezing previously frozen foods held for very prolonged times will further lower the quality.
Quality vs Safety
The safety of frozen foods decreases mainly when they thaw then become exposed to bacterial growth at unsafe temperatures. As long as frozen foods remain solidly frozen for years, they do not pose safety risks upon thawing and eating. However, the eating quality – flavor, texture, taste, aroma, appearance – will gradually diminish over years of frozen storage beyond recommended times even at constant 0°F temperatures. Freezer burned, dry sections may be unappetizing. Rancid fats and oils cause strong odors and flavors. While still edible, frozen foods held multiple years beyond stated storage times on packaging will be poor in quality and appeal.
How to Maintain Quality in Long-Term Frozen Storage
To maintain the highest quality when freezing foods for prolonged storage:
– Use high quality foods when freezing – very fresh, not near expiration
– Freeze foods at peak ripeness when flavors are best
– Prepare foods for freezing according to tested recipes and methods
– Package foods airtight to prevent freezer burn and moisture loss
– Ensure no air pockets in packaging
– Seal containers tightly
– Label packages with contents and dates
– Monitor freezer temperature to keep constantly at 0°F or below
– Organize freezer to cycle oldest foods to top
– Only freeze foods with tested recipes for long freezing times
– Consume foods by recommended freezer storage times
Proper packaging, freezing methods, temperature control, and aliquot sizes help retain quality in long-term frozen storage past normal times. But for best quality, abide by recommended maximum freezer storage durations.
Conclusion
While commercially frozen foods are safe to eat indefinitely when properly stored at 0°F, the quality slowly diminishes over prolonged storage beyond recommended times. Foods frozen for over 2 years will likely suffer degraded texture, flavor, aroma, and nutrition the longer the storage duration. But there are no actual food safety risks if the foods remain solidly frozen. For best quality, abide by recommended freezer storage times of 3 to 12 months for most frozen foods. Practicing sound freezing methods maximizes quality retention in long-term frozen storage situations. Monitor foods for rancidity, freezer burn, and other undesirable changes.
