Reefer temperature guide by commodity

Lowest safe transport temperatures

Many fruits and vegetables from warm climates are damaged by cold, even above freezing. The table below lists the approximate lowest temperature each can be carried at safely. Frozen food is the opposite: it should be carried at or below the value shown.

Source: UF/IFAS HS1328, Protecting Perishable Foods During Transport by Truck or Rail (Brecht et al.), revision of USDA Agriculture Handbook 669, October 2026

These are guides for checking, not setpoints. The setpoint the shipper puts on the bill of lading is the one you run, because the shipper knows the variety, the ripeness and where the load is going. A guide like this tells you when a setpoint looks wrong and is worth a question before you load. The list covers common chilling-sensitive produce and frozen food; for anything not listed, such as leafy greens, berries or meat, use the shipper's instructions.

How to use the guide on a load

• Check the setpoint. Compare the BOL setpoint with the guide. A setpoint colder than the lowest safe temperature for a chilling-sensitive item deserves a call to the shipper.
• Set the mode. Continuous run mode for fresh produce, chilled meat and other temperature-sensitive cargo; start-stop mode should not be used for fresh produce.
• Precool. Perishables should already be at or very near their carrying temperature when loaded; the trailer should be precooled. Precool the empty trailer to the setpoint before backing in.
• Check the product. Probe a few cases for pulp temperature and write the readings on the BOL before you sign.

Source: UF/IFAS HS1328, Protecting Perishable Foods During Transport by Truck or Rail (Brecht et al.), revision of USDA Agriculture Handbook 669, October 2026

Frozen loads

Frozen foods: 0°F (-18°C) or below. Frozen product should already be at that temperature when it's loaded; the trailer is there to hold it, not to freeze it. Check the product temperature with a probe before loading, precool the trailer, and keep door openings short on multi-stop deliveries, where every opening lets warm air in. Start-stop mode is common on frozen loads, but only if the shipper allows it on the bill of lading.

When temperature goes wrong

If the unit alarms, the setpoint drifts or the trailer runs warm, stop and record what happened: the unit display, the time, where you are and what you did about it. Call the broker straight away. A download from the unit and photos made at the time are what decide a claim later. Our temperature excursion checklist walks through it step by step.

Mixed loads

Two commodities with different safe temperatures shouldn't share a single-temperature trailer unless the shipper has decided they can. Bananas and potatoes, for example, are seventeen degrees apart on the guide. If you're offered a mixed load, ask which setpoint applies and get it on the BOL; a multi-temperature trailer with separate zones is the usual answer for loads that truly need different temperatures.

Normal operating temperature for a semi truck

People sometimes mean the engine, not the trailer. A truck engine's normal coolant temperature is set by the engine maker and shown in the operator's manual; it has nothing to do with the reefer setpoint. The reefer unit is a separate machine with its own engine and its own settings.

Reefer loads, checked before your yes

A setpoint that doesn't match the product, a missing mode or no pulp range on the paperwork are the kinds of problems that turn into rejected loads. Our dispatchers check setpoint, mode, pulp range and appointments on every reefer load before it reaches you, and you still say yes or no. Our fee is 5% for one reefer with authority older than 6 months and 7% for 26 ft reefer box trucks. See reefer dispatch and the reefer dispatch guide.