Basic Steps for Freezing Foods
Date: May 1989 (Revised April 1995)
Source: NDSU Extension Service Nutrition Specialists
For high quality frozen foods, start with high quality fresh food. Freezing will retain quality, but cannot improve it.
Work under sanitary conditions. Have all necessary equipment and packaging materials ready before you begin to work with the food.
Choose packaging materials that will prevent air contact with the food and moisture loss from it. For semi-fluid foods, use rigid plastic or wide-mouth glass containers you can close tightly. For more solid foods, you can use freezer bags, heat-sealable bags, coated freezer paper or heavy-duty aluminum foil. You can reuse plastic containers originally used for frozen foods if you can clean them thoroughly. Do not reuse paper cartons that originally held milk, cottage cheese or similar products.
Blanch or steam all vegetables and cool them quickly in ice water before freezing. This step inactivates enzymes that will damage flavor, nutrients and texture during freezer storage.
You can freeze fruits with or without sugar. Those you freeze with some sugar however, will have better texture and color. Use an antioxidant like ascorbic acid or citric acid to keep light-colored fruits like apples, peaches, or red cherries from discoloring.
Repackage meats you purchase at the supermarket before freezing them for long-term storage. The wrap used on fresh meats will allow oxygen to contact the surface of the meat. The meat will get freezer burn if you store it in the freezer for more than a few weeks. For short storage, just place the supermarket wrapped meat in a tightly closed plastic bag before freezing.
Freeze foods as quickly as possible. This helps form tiny ice crystals that will not damage the food as much when it is thawed.
Be sure to keep the freezer at 0 degrees F or lower to protect food quality.
Use all products within a reasonable time. Keep an inventory of food in the freezer to help you determine this. As long as food is kept solidly frozen, it will not become unsafe to eat. But it will lose quality during extended storage--nutrients, flavors and appearance will decline.
If you have further questions, contact your county office of the NDSU Extension Service.
Refreezing Food
Date: May 1989 (Revised April 1995)
Source: NDSU Extension Service Nutrition Specialists
Occasionally, frozen foods are partially or completely thawed because of delays in storing food, a power outage, or a change of plans for cooking the food.
The basis for determing safety in refreezing foods is how long and at what temperature they have been held. Look closely at frozen foods you thawed partially or completely to determine whether you should refreeze them.
Refreezing needs to be done quickly. Clean the freezer before refilling. If the freezer has an adjustable temperature control, turn it to the coldest position.
Check each package or container of food. Non-rigid containers can often be checked without opening by squeezing to feel for ice crystals. If they need to be opened, they should be carefully rewrapped.
Certain foods may be safely refrozen if they still contain ice crystals, or if they are still cold--about 35 to 40 F--and if you held them no longer than one or two days at that temperature. Put the relabeled packages in the coldest part of the freezer leaving space for circulation, and use within two or three months as quality is diminished.
Any signs of spoilage, off odors or color in any food indicates the food should be disposed of without tasting.
Meats such as beef, pork, veal, lamb and poultry can be refrozen when they are still firm with ice crystals. Meat still safe to eat can be cooked and refrozen. Discard meats if any signs of spoilage are present.
Fruits usually ferment when they start to spoil which will not make them dangerous to eat but will spoil the flavor. Defrosted fruits that smell and taste good can be refrozen.
Thawed fruits suffer in appearance, flavor and texture from refreezing; if they do, you can make them into jam.
Vegetables should be refrozen only if they contain plenty of ice crystals and still have a firm-to-hard core of ice in the center. Spoiled vegetables can be dangerous.
Shellfish, prepared foods or leftovers should not be refrozen if defrosted. If the condition of the food is poor or even questionable, get rid of it. It may be dangerous.
You can cook and eat thawed food mixtures like casseroles, pot pies, dinners, or pizzas if you are certain they have not reached a temperature above 40 F for more than one to two days. Do not refreeze these foods.
Never refreeze melted ice cream, cream pies, eclairs or similar foods.
Unfrosted cakes, uncooked fruit pies, bread, rolls, and similar bakery rolls can be refrozen. Their quality may suffer, but they will be safe to eat.
The investment in the foods in your freezer may be significant, but so are the benefits of serving safe foods.
If you have further questions, contact your county office of the NDSU Extension Service.
