Temperature-controlled freight adds an entire layer of risk that dry van shipping doesn't have. When a dry van shipment fails, you lose the freight value. When a reefer shipment fails, you lose the freight value plus face potential food safety liability, regulatory action, and customer relationships that took years to build.

The standard carrier qualification process — authority, insurance, CSA scores — is necessary but not sufficient for reefer carriers. Here's what to add.

The Temperature Failure Problem

Temperature excursions — freight going above or below the required temperature range during transit — are the most common cause of refrigerated freight claims. They happen for predictable reasons:

Reefer unit mechanical failure. The refrigeration unit itself fails, and the driver either doesn't notice or ignores the alert. Reefer units require regular maintenance that goes beyond standard truck maintenance. Compressors fail. Refrigerant leaks. Evaporator coils ice up. Control sensors drift out of calibration.

Fuel runout. Reefer units run on separate diesel tanks from the truck engine. If the reefer fuel runs out during transit and the driver doesn't refuel, the unit stops cooling. This is a management and routing problem more than a mechanical one.

Pre-cooling failures. The trailer wasn't properly pre-cooled before loading. The carrier either didn't pre-cool or didn't allow enough time to reach setpoint. The freight loads warm, and the reefer unit struggles to pull the temperature down during transit.

Door seal failures. Damaged or worn door seals allow ambient air to enter the trailer, forcing the reefer unit to work harder and potentially allowing temperature excursions in certain zones of the trailer.

Improper loading. Blocking airflow within the trailer by loading too tightly or not using proper loading patterns prevents the refrigeration system from maintaining uniform temperature throughout the cargo space.

What to Check Beyond Standard Metrics

Reefer Unit Maintenance Records

Ask the carrier about their reefer unit maintenance program. Key questions:

How often are reefer units serviced? (Industry standard is every 1,500-2,000 engine hours or quarterly)
Who performs the maintenance? (In-house shop or authorized dealer?)
Do they track reefer unit breakdowns and mean time between failures?
What is the average age of their reefer fleet?

A carrier that can answer these questions specifically has a real maintenance program. A carrier that gives vague answers probably doesn't.

Temperature Monitoring and Recording

Modern reefer units have data loggers that record temperature throughout transit. Some carriers use advanced telematics that provide real-time temperature visibility.

Ask whether the carrier:

Uses continuous temperature recording during transit
Can provide temperature logs for every load (pre-trip, transit, delivery)
Has real-time temperature monitoring with alerts to dispatch
Maintains temperature records for regulatory compliance

For food shipments subject to FSMA (Food Safety Modernization Act), temperature records aren't optional — they're legally required. A carrier that can't provide load-specific temperature documentation isn't equipped for food-grade reefer freight.

FSMA Compliance (Food Shipments)

The FDA's Sanitary Transportation of Human and Animal Food rule (21 CFR Part 1, Subpart O) imposes specific requirements on carriers transporting food:

Written procedures for temperature control during transport
Cleaning and sanitation procedures for trailers between loads
Training records for personnel involved in food transportation
Records demonstrating compliance, maintained for 12 months

If you ship food products, verify that your reefer carrier has a documented FSMA compliance program. This isn't covered by FMCSA safety data — it's a separate regulatory framework, and compliance is the shipper's responsibility as much as the carrier's.

Trailer Condition

Reefer trailers have components that standard dry vans don't:

Insulated walls, floor, and ceiling that degrade over time
Door seals that wear and leak
Air chutes and ducts that direct cold air flow
Drain plugs that must be properly positioned
Interior walls that must be clean and free of contamination

Ask about trailer age, insulation condition, and inspection protocols. A 15-year-old reefer trailer with degraded insulation will struggle to maintain temperature on a 1,500-mile haul, regardless of how well the reefer unit works.

Cargo Compatibility Procedures

Does the carrier have procedures to prevent cargo contamination?

How do they prevent cross-contamination between loads? (Cleaning protocols between food and non-food loads)
Do they segregate food-grade trailers from general-use reefer equipment?
How do they handle multi-stop loads where different temperature requirements may apply?

A carrier that uses the same reefer trailer to haul produce on Monday and industrial chemicals on Wednesday — even with cleaning between loads — represents a food safety risk that CSA scores won't capture.

Red Flags Specific to Reefer Carriers

No temperature records available. If a carrier can't produce temperature logs from recent loads, they either don't monitor temperature or don't keep records. Neither is acceptable for temperature-sensitive freight.

High vehicle maintenance CSA scores. Vehicle maintenance issues on a reefer carrier mean both truck and reefer unit maintenance may be lacking. A carrier that can't keep their trucks in compliance is probably not investing in reefer unit maintenance either.

Unwillingness to commit to temperature requirements in writing. If a carrier won't put your required temperature range and pre-cooling requirements in the rate confirmation, they may not be confident in their ability to meet them.

No FSMA documentation. For food carriers, inability to produce FSMA compliance documentation — written procedures, training records, sanitation protocols — is disqualifying.

The Qualification Process for Reefer Carriers

Standard carrier qualification (authority, insurance, CSA scores, OOS rates) plus:

Reefer unit maintenance program documentation
Temperature monitoring and recording capability
FSMA compliance program (for food shipments)
Trailer age and condition information
Cargo compatibility and cleaning procedures
References from other temperature-controlled shippers
Written agreement on temperature requirements and pre-cooling

It's more work than qualifying a dry van carrier. The freight demands it. A temperature-controlled shipment that arrives at the wrong temperature isn't just a cargo claim — it can be a food safety incident, a regulatory violation, and a customer relationship disaster.