Best Practices to Mitigate Risk Transporting Produce

DRC’s Trading Assistance Staff has contacted Thermo King to understand better how a reefer unit operates and to learn what they recommend as best practices for transporting fresh fruits and vegetables. Here’s a list containing valuable insights you can use when preparing your next load:


✔ Pre-cool and store cargo at a desired temperature to remove heat.

  • Confirm the product is at the desired temperature before loading.
  • Refrigeration units are designed to maintain temperature, not to change it.

Run Reefer Unit 20 Minutes in “High Speed Cool”.

  • To remove residual trailer/body heat.
  • Perform Automatic “Pre-Trip” to confirm proper unit operation.
  • Unit: MUST” pass test.
  • If Auto Pre-Trip fails, follow your company’s prescribed procedures, or contact your local dealer for assistance.

Set unit controller to the desired temperature.

  • Verify the settings after changing it to confirm that it is correct.

Select Mode of Operation.

  • “Continuous Run” or “Cycle Sentry”. For fresh fruits and vegetables, always run the unit on the “Continuous Run” mode.

Pre-cool trainer and truck body.

  • To desired temperature to remove residual heat.

Turn the unit “OFF” while loading.

  • To minimize heat and humidity entering trailer / truck body.
  • Verify product is at proper temperature.

Load Product quickly and efficiently.

  • Provide adequate air circulation around and through the entire load.

Close doors and start unit.

  • Re-confirm Continuous Run operating mode and set point temperature.

Strip curtains.

  • Always recommended in distribution.
  • Keep conditioned air in and outside air out.

Door openings.

  • Minimize the number door openings and their duration.
  • Ambient air migrates in, and trailer / body air migrates out.

Proper airflow is CRITICAL.

  • Poor air distribution causes product deterioration, even with adequate unit capacity.
  • Obstructions cause poor air flow and product hot spots.
  • Proper air circulation: Unobstructed paths on all 6 sides of load.

Good airflow has 4 Key Factors:

  • Use three-way block pallets to help provide adequate air flow.
    • Do not obstruct floor under cargo. It prevents air from returning to the unit.
  • Slip sheets and hand stacking are not optimal for temperature management.
    • Inside of trailer / body must be clean to prevent contamination:
    • T-Floor must be free of obstruction.
    • Debris can block air circulation.
    • Debris can be pulled into unit, resulting in insufficient cooling.
    • Use loading patterns that provide adequate air pace.
  • Exercise Caution!
    • Provide adequate air space between top of the cargo and ceiling.
    • Products should be loaded evenly to avoid air flow restrictions.
  • Do not block unit evaporator air inlet (return air). It restricts air flow.
    • Do not load product tight against unit, walls, or doors.
    • Do not load product to ceiling. It causes air to short cycle.

Verify Pre-cooling.

  • Pre-cooling product and trailer / body to desired temperature prior loading.
  • Position trailer / body tight against dock seals when delivering. Supervise opening and closing of doors.

Do not operate unit with doors open.

  • Until will blow conditioned air out and draw outside air in.

Keep doors closed whenever possible.

  • Keep door openings few and fast. Cold stays in, heat out.
  • Turn unit “off” before opening doors.
  • Box temperature recovery time is significantly increased by the entry of outside air.
  • The greater the difference between set-point temperature and actual box temperature, the longer it will take to recover back to set-point.

Use strip curtains.

  • Strip curtains reduce internal and external air exchange. This helps to limit interior temperature changes.

Non-refrigerated docks:

  • Turn refrigeration unit “off”. Minimize product exposure to ‘improper temperature areas.’
  • Maintain an effective seal between trailer / body and dock.

Refrigerated docks and refrigerated cross docks:

  • Back trailer / body tightly against docks seals before opening doors.
  • Minimize door openings.

Cross docks distribution:

  • Move product quickly. Minimize the time it will be exposed to ‘improper temperature areas.’

Ground delivery for:

  • Supermarkets
  • Convenience stores
  • Restaurants
  • Direct Store Delivery

Turn refrigeration unit ‘off.’

Minimize door openings.

Use strip curtains.

The information in this article was provided by Randy Green of Thermo King Eastern Canada, Ontario Division.

Contact: Randy Green at [email protected]

Thermo King

Thermo King, founded in 1938, is the world leader in manufacturing transport temperature control systems for a variety of mobile applications including trailers, truck bodies, buses, shipboard containers, and railway cars. Thermo King products are backed by a nationwide dealer network which provides expert factory-trained service and a complete line of genuine and competitive parts.

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