Cold Chain Protocol - Vaccines and Biologics
Appendix 2: Defrosting a Refrigerator/Freezer
Frost-free freezers do not need to be manually defrosted. They have regular defrosting cycles three or four times a day when the freezer temperature increases and melts the ice automatically.
For freezers in non-frost free refrigerators:
- Remove all products from both compartments of the unit and place them into alternate storage unit(s) in accordance with written protocols.
- Turn off the power and unplug the unit.
- Remove all frozen packs from the freezer (keep frozen, if possible).
- Keeping the freezer door open, allow all the frost to melt.
- Loose ice can be removed by hand; no sharp tools or sharp instruments should be used to remove the ice.
- A container of warm water (not greater than +50°C) inside the compartment can reduce defrosting time.
- Once the frost has melted completely, clean thoroughly and wipe the unit dry. (This is also a good time to clean the refrigerator compartment).
- Connect the power and ensure that the thermostat is turned to an appropriately cold setting.
- Wait for each compartment of the unit to stabilize at the proper temperature range.
- Monitor and record the temperature every half hour for the next few hours until stable temperatures between +2.0 and +8.0°C have been reached in the refrigerator.
- Vaccines and biologics that require to be stored frozen should be in a freezer that is maintained at -15°C or colder.
- Re-stock each compartment with the product.
- Continue to monitor and record the temperature every half-hour for the next few hours.
- If defrosting is necessary once a month or more frequently, the door may not be sealing properly, the door may have been opened too frequently, or there may be other mechanical problems with the freezer. Consult a technician and monitor temperatures carefully.
Communicable Disease
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