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University of Illinois Extension

Freezing & Freezer Containers

The enzymes in fruits and vegetables must be inactivated prior to freezing to help avoid color and flavor changes, as well as loss of nutrients. Enzymes in vegetables are inactivated by blanching while enzymes in fruits are controlled by using chemical compounds, such as ascorbic acid (vitamin C).

Select fruits and vegetables suitable for freezing. Frozen melon is not allowed in a cottage food operation. See the list from National Center of Home Food Preservation of foods that do not freeze well. Choose fresh, young, tender vegetables and fresh, firm-ripe fruits.

Containers for Freezing

  1. Rigid containers- made of plastic or glass and often reusable, such as plastic freezer containers with tight-fitting lids or wide-mouth canning jars. Do not use regular glass jars; they break easily at freezer temperatures.
  2. Flexible bags or wrappings- plastic freezer bags and moisture-vapor resistant wrapping materials, such as plastic freezer wrap, freezer paper and heavy-duty aluminum foil are suitable for dry packed foods with little or no liquid. Bags can also be used for liquid packs. Press to remove as much air as possible before closing.

Several materials are not good for long-term storage of frozen food. Foods stored in these materials for long periods of time may develop freezer burn and absorb undesirable odors. The materials include wax paper, paper cartons, cottage cheese cartons, cardboard ice cream or milk cartons, any rigid container that may crack and any container that has a poorly fitting lid. Do not freeze fruits and vegetables in containers over one-half gallon; foods freeze too slowly.

Vacuum packaging removes more air from the package than could be pressed out. It is important to note, however, that this removal of air and oxygen does not eliminate the possibility for bacterial growth. While it may limit spoilage bacteria (bacteria that causes deterioration), a vacuum package environment may actually accelerate the growth of pathogens such as Clostridium botulinum. These pathogenic bacteria can cause serious illness and death. Vacuum packaging cannot be used as a food preservation method alone. Important steps must be taken when vacuum packaging perishable foods for refrigerator or freezer storage. Follow manufacturer’s directions carefully for your appliance.

Best Practice: Do not use vacuum packaging in a cottage food operation.

See National Center for Home Food Preservation for more information.

Leave appropriate headspace

Leave space between packed food and closure of the package to allow fruits and vegetables to slightly expand. Containers with wide top openings generally need ½-inch headspace per pint and 1-inch headspace per quart. Containers with narrow openings generally need a little more headspace unless using a dry pack.