MSU Extension Food Preservation

Every year consumers call the United States Department of Agriculture (USDA) Meat and Poultry Hotline and Michigan State University Extension asking if food items are safe in their home freezers. Understanding the concepts from the USDA can help avoid some of the freezing confusion.

Freezing food and maintaining it at 0° Fahrenheit will keep it safe. The quality could suffer during lengthy freezer storage. Freezing keeps food safe by slowing down the movement of molecules, causing microbes to enter a dormant stage. The freezing process preserves food for extended periods because it prevents the growth of microorganisms that cause both food spoilage and foodborne illness.

Proper packaging materials for freezing food protects the flavor, color, moisture content and nutritive value of foods from the harsh climate inside the freezer. Using inappropriate containers will give your food inadequate protection and reduce the quality of the product.

Exactly which container to choose depends on the type of food to be frozen and your personal preference. Do not freeze fruits and vegetables in containers with a capacity over one-half gallon. Foods in larger containers freeze too slowly which results in an unsatisfactory product. In general, packaging materials must have these characteristics:

• Moisture vapor resistant
• Durable and leak proof
• Do not become brittle and crack at low temperatures
• Resistant to oil, grease and water
• Protect food from absorption of off-flavors or odors
• Easy to seal
• Easy to mark

Cartons for cottage cheese, ice cream and milk do not resist moisture vapor sufficiently to be suitable for long-term freezer storage.

Rigid containers and flexible bags or wrapping are two general types of packaging materials that are safe for freezing.

Rigid containers made of plastic or glass are suitable for all packs and are especially good for liquid packs. Straight sides on rigid containers make the frozen food much easier to remove. Rigid containers are often reusable and make storage in the freezer easier because they can be stacked.

Regular glass jars break easily at freezer temperatures. Choose wide mouth, dual-purpose jars made for freezing and canning if you wish to use glass. These jars have been tempered to withstand extreme temperatures and the wide opening allows easy removal of partially thawed food. Covers on rigid containers should fit tightly, if they do not, reinforce the seal with freezer tape. Freezer tape is especially designed to stick at freezing temperatures.

Flexible freezer bags and moisture vapor resistant wrapping materials such as plastic freezer wrap, freezer paper and heavyweight aluminum foil are also suitable for dry packed products with little or no liquid. Bags can also be used for liquid packs. Bags and wraps work well for foods with irregular shapes. Remove as much air as possible before closing for best results.

Ensure that your efforts to freeze foods result in delicious meals at a later date. Remember that the type of container you choose when freezing food can make a difference in the quality of the end product. Your choice of proper freezer packaging materials makes for tastier food.

MSU Extension recommends you also keep an appliance thermometer in your freezer. In the event of a power outage, this device will help you determine if your food is still safe to keep or consume. Following these simple guidelines will allow your foods to remain safe while frozen.

Michigan State University Extension offers programs related to food preservation, food safety, food health and more. To find a program near you visit http://msue.anr.msu.edu/events.