Glossary
Reefer
Shorthand for a refrigerated trailer or truck body. A reefer's cooling unit failing, or a door left open too long, is the specific risk cold chain temperature monitoring is built to catch before a load is lost.
What Reefer means in practice
A reefer is a refrigerated trailer or truck body, and its main risk is that it fails quietly. A compressor can stop, or a door can stay open too long at a delivery stop, while the trailer is hours from anyone watching. Multi-stop routes carry more of that risk, since every stop is another door opening.
Monitoring works best when it measures the product rather than the air. A Bluetooth temperature puck placed at product height, about two-thirds of the way back and away from the evaporator discharge, reads the load and reports through the GPS tracking device. Set the alert band a degree or two wider than the product specification, with a delay of a few minutes, so a door opening does not page the dispatcher but a compressor failure does.
Multi-compartment trucks under pharmaceutical or similar audits usually need wired, calibrated probes in each compartment instead. Either way, the per-trip log ties each reading to a time and location, which becomes the delivery record.
Read the full explainer
The definition above is the short version. The page below explains Reefer in depth, with the rules, numbers and examples behind it.
Cold Chain Compliance for Food & Beverage FleetsGuides that explain Reefer
- How Does Trailer GPS Tracking Work, With or Without a Truck?
- GPS Fleet Tracking for Food and Beverage Distributors: Routes, Temperature and Delivery Windows
- Trailer Tracking Software and Systems: Reports, Alerts and Integrations
- One Bluetooth Gateway for Thirty Sensors on a Truck or Trailer
- Bluetooth Temperature Sensor Puck: A Ten-Year Wireless Thermometer for Reefers and Coolers
- Wired Reefer Temperature Monitoring for Multi-Compartment Refrigerated Trucks
Reefer: common questions
What temperature should a reefer trailer maintain?
It depends entirely on the product. Frozen foods, fresh meat and seafood, dairy, produce and pharmaceuticals each have their own safe range, and the product specification or customer contract sets the real numbers. There is no single universal setting, which is why the alert band in a monitoring system should be set for each product the reefer carries.
Where should a temperature sensor go in a reefer trailer?
Mount it at product height on the wall, about two-thirds of the way back, away from the evaporator's discharge, so it reads the load and not the coldest air. Use one sensor per compartment. In a tote or cooler, place the sensor against the product rather than the lid, since the product temperature is what matters.
Should I use wireless pucks or wired probes in a reefer?
Bluetooth pucks suit most food and beverage distribution: no wiring, a battery of about ten years, and readings every few seconds. Choose wired, calibrated probes in each compartment when a contract or regulation requires continuous, calibrated monitoring, such as pharmaceutical distribution or certain meat and seafood programs. Many fleets run both.