Using Dry Ice to Keep Food Cold
Julie Garden-Robinson, Food and Nutrition Specialist
Dry ice may be used to keep food cold in a freezer in an emergency situation. Dry ice is not always easy to find. Check the telephone book yellow pages, with your power company, or with a local dairy or cold-storage warehouse.
Dry ice registers a temperature of minus 216 degrees F., so use it with care. Follow these guidelines:
- Wear gloves when handling dry ice.
- Allow 2½ to 3 pounds of ice per cubic foot of freezer space. A 50-pound block of dry ice should keep food safe in a full 18-cubic-foot freezer for at least two days. More will be needed in upright freezers, and ice should be placed on each shelf. Your supplier may be able to cut blocks into slabs.
- If food from upright freezers can be tightly packed in coolers with dry ice, it may be easier to keep the food frozen for a longer period of time.
- If a freezer has a limited amount of food in it, pack the food compactly in coolers with dry ice.
- Fill a partly empty freezer with material like crumpled newspaper, clean bath towels or blankets to cut down on air circulation, which hastens dissipation of dry ice.
- Some suggest separating dry ice from direct contact with food packaging by placing boards or heavy cardboard between packages and ice. Ice may be wrapped in brown paper for longer storage.
- As dry ice dissipates, it becomes a gas. To avoid gas fumes, wait a few moments after opening the door of a chest freezer before bending over it. Stand back a bit when opening the door of an upright freezer.
Source: U.S. Department of Agriculture