Cold Chain Protocol - Vaccines and Biologics

Appendix 1: Instructions for Refrigerator and Temperature Monitoring Maintenance

Weekly/Monthly Maintenance

  1. Check for Ice Build Up in Freezer
    • If you have a manual defrost freezer, it is quite normal for ice and frost to accumulate inside the compartment.
    • A thin layer of frost does not affect the cooling performance but a thick layer of frost negatively affects the efficiency of the system.
    • When frost has accumulated to a thickness of 1cm or so, the unit requires defrosting.

Quarterly Maintenance

  1. Clean Coils and Motor – Dust and dirt build up affects the transfer of heat from the coils and, therefore, the efficiency of the unit.
    • Unplug the unit and use a soft brush, cloth, or vacuum cleaner with an attachment hose to remove any dirt or dust from the surface of the coils.
    • After cleaning, plug in the unit and document that the power is restored and that the temperature has been maintained.
    • Avoid cleaning the coils and motor at the end of a working week. Accidentally damaging the coils will cause a problem that may not be detected until the following working day.
    • This process should only take a few minutes; therefore, it is not necessary to transfer the product to another storage unit as long as the doors remain tightly closed for the duration of the procedure.

  2. Clean Inside of Fridge and Freezer – quarterly or as needed.
    • Remove the vaccines and biologics from the compartments and store them in a functioning unit.
    • Unplug the unit or turn off the power and wash all inside surfaces and shelves with warm, slightly soapy water.
    • Dry thoroughly then plug in the unit or turn the thermostat back to an appropriately cold setting.
    • Wait for the unit to stabilize at the proper temperature range monitoring and recording the temperature every half-hour for the next few hours.
    • Restock each compartment with the vaccines and biologics, continuing to monitor and record the temperature every half-hour for the next few hours.

  3. Door Seal – check the integrity of the door seals.
    • The door seals should not be torn or brittle and there should be no gaps between the seals and the body of the unit when the doors are closed.
    • The doors should open and close properly and fit squarely against the body of the refrigerator. For this to happen, the hinges must be correctly adjusted.
    • If there are any problems with the door seals, consult a technician as necessary and monitor temperatures carefully.

Annual Maintenance

  1. Thermometer Check – Thermometers and other temperatures recorders must be checked annually to ensure:
    • Temperature measurement is accurate via a Slush Test.
    • Batteries are maintained and changed regularly as recommended by the manufacturer, keeping in mind warranty requirements.
    • Cables or probes are not damaged.

  2. Centralized Alarm System Check – External monitoring services should be tested occasionally (like a fire drill) to ensure the service is able to function properly in the event of an actual cold chain failure.

Instructions to Conduct a Slush Test

  1. Fill a polystyrene or plastic cup two-thirds (2/3) with cold water. Place cup in the freezer until a fine layer of ice forms on top and a small section of ice forms within the fluid (about two (2) hours). If ice is present, this ensures the mixture is 0°C.
  2. Place the temperature probe in the middle of the cup (do not touch the sides)
  3. Observe the temperature after two (2) minutes. Within that time, the temperature should drop to 0°C.

Most thermometers are calibrated to ±1°C or better. If the temperature reading is more than 1°C above or below 0°C after two (2) minutes, replace the battery and test again. If temperature is still not within range, contact the thermometer manufacturer for instructions on recalibration or replace the thermometer.

Communicable Disease Control (CDC)
Public Health
Manitoba Health

4th Floor - 300 Carlton St.
Winnipeg MB  R3B 3M9  CANADA

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204-788-8200 or 1-888-315-9257