Reefer Freight Requirements: Temperature, Pre-Cool & Food Grade Rules

Temperature-controlled freight carries a different risk profile than dry freight. A mechanical failure, a missed pre-cool, or a carrier without the right food-grade certification can turn a routine load into a six-figure cargo claim. This guide covers what you need to verify as a broker before you tender a reefer load.

What Is a Reefer Trailer?

A reefer trailer is a refrigerated semi-trailer equipped with a self-contained refrigeration unit — typically mounted at the front of the trailer, over the landing gear, or on the nose. The unit runs on diesel and maintains the interior temperature throughout transit regardless of ambient conditions.

Modern reefers can maintain temperatures from -20°F (deep frozen) to 70°F (ambient controlled) and can be set to multiple temperature zones within a single trailer using a divider wall. Most carriers run 53-foot reefer trailers.

Temperature Zones

Shippers specify a temperature setpoint and tolerance. The setpoint is what the reefer unit targets. The tolerance is how far above or below the setpoint is acceptable before a claim is possible. Always confirm both when taking a load.

Common Produce Temperature Requirements

Produce is the most variable temperature category. Different fruits and vegetables have specific requirements — some are damaged by temperatures below their threshold even if they're above freezing.

Pre-Cooling Requirements

Shippers loading perishable freight typically require the trailer to be pre-cooled to the setpoint before they will load. Pre-cooling removes the heat from the trailer walls and floor so the refrigeration unit isn't overwhelmed when warm product is loaded.

• Standard pre-cool time: 1–3 hours at setpoint before loading
• Frozen loads: pre-cool to 0°F or lower before loading
• Some shippers require a temperature recorder to be running before arrival
• Carriers should idle the reefer unit for at least 30 minutes before arrival at the shipper to confirm the unit is functioning
• Always confirm pre-cool time with the carrier — arriving at a shipper with a warm trailer causes refusals and detention

Food Grade Trailer Requirements

Food grade is a trailer certification, not just a temperature setting. A food grade trailer has been inspected, cleaned, and certified as safe for direct food contact. Not all reefer trailers are food grade — some run non-food loads (chemicals, industrial products) that disqualify them from food service.

The FDA Food Safety Modernization Act (FSMA) Sanitary Transportation Rule (2017) puts the burden on shippers and carriers to prevent food contamination during transport. As the broker, you are not directly liable under FSMA, but your carrier must be.

• Ask every carrier quoting a food load: "Is the trailer food grade and has it been used only for food in the last load?"
• Carriers should have a cleaning log showing the last load, cleaning date, and cleaner's signature
• A trailer that hauled pesticides, pool chemicals, or non-food industrial products within the last 1–3 loads may be refused by the shipper
• Some shippers specifically require "dedicated food" trailers that have never run non-food loads
• Pharmaceutical and nutraceutical loads often have stricter requirements than standard food grade

What Happens During a Temperature Excursion

A temperature excursion is when the cargo exceeds its specified temperature range during transit. Excursions happen because of a unit failure, a door left open too long, improper loading, or the reefer unit running in "continuous" mode instead of "cycle." When an excursion occurs:

1. The carrier should notify the broker immediately — do not let them hold the information
2. Document the temperature recorder data — this is the key evidence for or against a claim
3. Contact the shipper or consignee to determine if the product is still acceptable
4. Do not allow the carrier to deliver without consignee agreement if the excursion is significant
5. If a claim is likely, document everything before delivery is completed — once product is accepted, claims become harder to pursue

Produce Commodity HOS Exception

The FMCSA's agricultural commodity hours-of-service exception allows drivers hauling certain perishable goods to extend their drive time beyond the standard 11-hour limit. This applies to livestock, insects, and specifically certain fruits and vegetables during specific transit conditions.

In practice, this exception applies within 150 air miles of the source. For most broker loads moving interstate, the standard HOS rules apply. Do not commit a shipper to a transit time that requires a driver to run outside HOS without confirming the carrier's eligibility for the exception first.

Reefer Broker Checklist

1. Get the temperature setpoint AND tolerance in writing from the shipper
2. Confirm pre-cool time required — how long before loading should the carrier arrive?
3. Ask if food grade is required and specify "last load must be food or food-grade industrial"
4. Confirm whether a temperature recorder (datalogger) is required and who provides it
5. Verify the carrier has a functioning reefer unit — ask when it was last serviced
6. Confirm transit time fits within HOS — perishables with tight windows need careful planning
7. Make sure the carrier knows whether to run the unit in continuous or cycle mode — ask the shipper

FreightLeads Pro

Carrier compliance built into every rate con

Live FMCSA authority and insurance check on every rate confirmation. If a carrier fails, the document locks — not a warning, a hard stop. Plus lead finder, dispatch, and invoicing in one place.

No credit card required