A reefer setting, an air sensor and a product probe describe different things. Understand those differences before comparing a shipment's records with written product instructions.
In This Guide
What It Means
- Reefer setpoint: the operating target selected on the refrigeration unit, not a measurement of every product.
- Supply-air temperature: air leaving the unit for the trailer, influenced by the unit's operating cycle.
- Return-air temperature: air returning to the unit after circulating, not necessarily the warmest or coldest part of the load.
- Product or pulp temperature: a measurement of the product using an appropriate method; it samples a particular item or location.
Why It Matters
These measurements are not interchangeable. Sensor location, operating cycle, door openings, load geometry, packaging and product thermal inertia can produce different readings. A trailer-air record does not prove the temperature of every pallet or establish product condition.
How It Works
Pre-cooling and maintaining conditions
A trailer is generally intended to maintain product conditions rather than rapidly cool warm product. Product pre-cooling and trailer pre-cooling are separate tasks. Confirm both when required by the shipper or product owner, along with setpoint, operating mode and acceptable loading conditions.
Airflow and loading
Use the equipment and shipper's loading instructions to maintain air paths around and through the load as appropriate. Blocked circulation and unsuitable packaging can create local differences even when a unit display appears normal. A generic spacing rule cannot replace the actual equipment and product instructions.
Common Challenges
- Comparing a return-air display directly with a pulp measurement
- Missing sensor location, calibration information or Celsius/Fahrenheit units
- Treating gaps between recorded readings as proof of unchanged conditions
- Assuming a brief spike or an average reading establishes safety or product disposition
Best Practices
At pickup and delivery, document time, measurement type, units, sensor or probe location, method, product identification, available calibration information, written requirements and relevant door or handling events. Preserve original logger files and identify missing periods. Follow the shipper's procedure for product measurements and escalate discrepancies to the responsible product owner or quality team; this guide does not advise acceptance, rejection or release.
This is OTR transportation-planning guidance, not legal advice, food-safety certification, product-disposition or carrier approval, a substitute for shipper SOPs or product-owner instructions, or a guarantee of shelf life or condition. The shipper or responsible product owner supplies temperature and handling instructions; receiver requirements and qualified specialists govern product decisions.
When to Use This Service
Prepare your produce handoff and use the tools as planning references, not shipment approval.
Official references: CFIA explains applicable Canadian preventive-control requirements; FDA explains the U.S. sanitary-transportation rule and role-based responsibilities, including scope, exemptions and agreements. These are distinct from OTR planning recommendations. The USDA handbook is historical technical guidance, not a current regulation or universal commodity-temperature prescription. Check applicable current requirements with the responsible shipper, importer and appointed customs broker.
Read fresh-produce transportation guides and the reefer setpoint and product-temperature guide.
Planning references only—not legal advice, food-safety certification, product-disposition or carrier approval, substitutes for shipper SOPs or product-owner instructions, or guarantees of shelf life or product condition. Confirm written instructions with the responsible parties.
Numerical commodity examples are general references, not universal transport temperatures or shipment instructions. Follow the product owner’s, shipper’s and receiver’s current requirements.
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