Refrigerated Transport Built Around Your Set Point
Temperature-controlled freight where the profile is decided before the truck is booked, not at the dock: precool, set point, continuous or cycle air, and the pulp reading that goes on the bill of lading. One specialist owns the lane, the assigned carrier and its unit are verified for that profile the day the truck is assigned, and the reefer's own log comes back with the freight if a receiver ever disputes the temperature.
What is refrigerated transport?
Refrigerated transport moves freight in an insulated trailer with a mechanical unit that holds a commanded temperature, heats as well as cools, and logs what it actually delivered. The unit is sized to maintain a set point, not to pull field heat out of warm product, which is why the trailer is precooled and the product loaded already at temperature. What separates it from any other truckload move is the data record that arrives with the freight, because that record is what a receiver checks before the pallets come off.
Cold Chain Freight We Coordinate
- Fresh produce from the Rio Grande Valley and the Mexican growing regions: citrus, onions, leafy greens, peppers, avocados
- Frozen protein and seafood at 0°F or below
- Fresh meat and poultry on deep chill, 28 to 32°F
- Dairy, eggs and refrigerated deli at 34 to 38°F
- Ice cream, frozen dough and par-baked goods, which run colder than standard frozen
- Pharmaceuticals and diagnostics on a 2 to 8°C profile with a required temperature record
- Chocolate, confection and cosmetics that fail on heat long before they fail on cold
- Beverages, canned goods, latex paint and adhesives that only need to stay above freezing
- Floral and nursery stock on a chill-sensitive profile
Who Ships This
- Produce shippers and repackers on a harvest clock, where a day of delay is a day of shelf life
- Food manufacturers and co-packers whose receivers reject on temperature and on lateness
- Grocery and foodservice distribution centers that enforce appointment windows and pull the log at the door
- Pharmaceutical and life-science shippers who need the temperature history as part of the release paperwork
- Beauty and specialty chemical brands whose product separates or freezes, and needs protection in only one direction
- Importers bringing Mexican produce north through the South Texas crossings
Precool the trailer, pulp the product, or the set point is only a suggestion
A reefer unit is a maintenance machine. Its capacity is sized to hold a box at temperature and remove the heat that leaks through the walls, not to chill warm product. Load 60°F product into a trailer commanded to 34°F and the unit can run wide open the whole trip and still deliver warm freight, and the temperature log will show exactly that.
So the trailer gets pulled to set point before loading, then the unit is switched off while the dock doors are open, so it is not inhaling humid dock air and frosting its own coil. Then the product gets pulped: a probe into the product itself, between the boxes, on pallets from different parts of the load, with the readings written on the bill of lading. Air temperature at the door proves nothing. Pulp temperature decides whether the load leaves at spec, and later it decides whose problem a warm delivery is.
Continuous air or cycle air is a decision, not a default
A reefer runs one of two ways. On continuous, the evaporator fans never stop, air keeps moving through the load, and the temperature band stays tight. On cycle, the unit shuts down at set point and restarts when the box drifts, which saves fuel and engine hours.
The difference shows up in the corners. With the fans off the air stops moving, and the pallets nearest the rear doors and the front bulkhead drift first. Frozen product at 0°F has the thermal mass to ride through it. Respiring product does not: fresh produce makes its own heat and gives off gases, so it needs air exchange as much as it needs cold. Put strawberries in a cycling trailer for two days and the top layer of the back pallets tells the story at the receiver. Carriers default to cycle unless the load says otherwise, so run mode goes on the dispatch in writing, next to the set point.
A dry van with ice in it is not refrigerated transport
It comes up every season, usually as a way to save money on a short run. Ice, gel packs or dry ice in the nose of a dry van will keep product cold for a while. What none of it does is hold a temperature. No thermostat, no set point, no forced airflow through the load and no record, so a receiver who asks for the temperature history gets nothing.
The failure mode is worse than merely warm. Ice melts into the load and across the floor, wetting cartons that were never built to be wet, and the meltwater ends up in the rejection photos. Dry ice sublimates into carbon dioxide inside a sealed van, which is a real hazard for whoever opens those doors and a regulated material with its own paperwork in quantity.
Refrigerated versus a protected dry van, when freezing is the only enemy
A large share of what gets booked as reefer freight has no upper temperature limit at all. Canned goods, bottled beverages, latex paint, adhesives and plenty of cosmetics do not care about heat in any range a trailer will realistically see. One thing ruins them: freezing. So the real question is not reefer or dry van, it is whether the route and the calendar carry a freeze risk.
A dry van buys you a wider carrier pool, a lower rate, faster coverage and no reefer fuel on the invoice. A reefer set at 35 to 40°F with heat enabled buys insurance against one specific event. South Texas to Houston in June does not need that insurance. The same freight routed through the Plains or the Midwest in January does.
The honest line: if your product survives ambient, no downstream customer requires a temperature record, and the lane stays out of freezing weather, refrigerated transport is money you do not need to spend. It earns its cost when there is a ceiling as well as a floor, when a receiver or a regulator will demand the data file, or when the lane crosses a freeze line in the season it actually freezes.
The download is the evidence, and it has a shelf life
Every modern reefer unit logs itself: set point, supply air, return air, ambient, defrost cycles, unit on and off events and, on most units, door openings, all time-stamped at an interval you can set. That file is the download, and on a temperature claim it is most of the case.
Read alongside the pulp temperatures at both ends, it answers the only question that matters: where did the product warm up, and who had it then. Set point held all trip with a two-hour rise at a delivery stop points at doors open at that stop. The unit off for six hours overnight points somewhere else. Ask for the download at delivery, while the trailer is still at the dock, because units overwrite older data as memory fills and later retrieval becomes a favor rather than a procedure.
Dobie works that file the same way on every cold load. Pulp and condition are recorded at pickup and again at delivery, so the download has two fixed endpoints instead of one open end. The freight travels covered by the assigned carrier's cargo insurance between those endpoints, and the certificate is verified the day that truck is assigned, not once a year. The desk that runs these lanes is the internal team built for freight other than vehicles and machinery, with refrigerated, food and hazmat experience behind it.
The Pharr corridor runs on fresh produce, and the cold chain has to survive the wait
South Texas is the gateway for a large share of the fresh fruit and vegetables entering the United States from Mexico, and the Pharr crossing is the produce door. Dobie is based in the Rio Grande Valley, so those crossings, the customs brokers, the staging yards and the Mexico-side carriers are weekly business, not an exotic add-on.
What makes a reefer different from any other cross-border load is that its clock never stops. A dry van waiting for release is simply parked. A reefer waiting for release is burning fuel and holding a set point in a yard in July, and every hand-off is a chance for the unit to be shut down: the tractor changes at the transfer yard, the trailer moves between carriers, an inspection opens the doors on product that has been holding 34°F since the grower's dock. So the plan is built around the wait. Full fuel on the unit before it stages, continuous air through the crossing for respiring product, and set point margin for door-open time instead of the exact number off the spec sheet.
Temperature Profiles and Reefer Facts That Decide the Booking
The commodity sets the number. The number sets the equipment, the run mode and the size of the carrier pool.
| Frozen, general | 0°F (-18°C) or below. Ice cream and frozen dough run colder, often -10°F to -20°F. |
|---|---|
| Fresh meat and poultry | 28 to 32°F. Below standard refrigeration, above the point the product freezes. |
| Dairy, eggs and deli | 34 to 38°F, with shell eggs commonly specified at 45°F or below. |
| Most fresh produce | 34 to 38°F on continuous air. Respiring product needs exchange, not only cold. |
| Chill-sensitive produce | Bananas, avocados, tomatoes and squash take chilling injury below roughly 50 to 55°F. |
| Pharmaceutical cold chain | 2 to 8°C, 36 to 46°F, with a record the receiver reviews before the pallets come off. |
| Controlled room temperature | 15 to 25°C, 59 to 77°F. The unit heats as well as cools to hold that band. |
| Protect from freeze only | Around 35 to 40°F with heat enabled. The floor matters, the ceiling is ambient. |
| Trailer precool | Pulled to set point before the doors open, unit off during loading. |
| Pulp temperature | Probe into the product, on pallets from across the load, recorded on the bill of lading. |
| Run mode | Continuous keeps the fans turning and the band tight. Cycle saves fuel and lets corners drift. |
| Payload | Unit, fuel and insulation outweigh a dry van's, so usable payload runs lower against the same 80,000 lb federal gross limit. |
| Data download | Set point, supply and return air, defrost cycles and door events, time-stamped. The evidence file on a claim. |
How a Refrigerated Load Gets Booked and Moved
Send the profile, not the word reefer
Set point in F or C, fixed or a range, run mode, the precool you want on the trailer, whether a wash-out and the last three commodities have to be documented, and whether your receiver pulls the log at the door. Those answers decide which carriers can even be offered the load.
Carrier and unit verified for the profile, not just for the lane
Active operating authority, current insurance with limits that fit the commodity, and equipment that fits the assignment: single temp or multi temp, able to run continuous if the commodity respires, fuel on the unit for the wait at a border or a receiver's yard, and a trailer that can produce wash-out and last-three-commodities documentation when the load is food grade. Certificates are checked the day the truck is assigned, not once a year.
Precool, pulp, load for airflow
Trailer pulled to set point before the doors open, unit off during loading. Pulp readings taken and noted on the bill of lading. Freight loaded off the front bulkhead so return air can reach the evaporator, off the rear doors, and below the ceiling chute so the discharge is not capped, because a solid wall of product cooks its own center.
Deliver on the window, pull the file
Arrival inside the appointment window, because a produce receiver refuses a late reefer as fast as a warm one. Pulp check at the door, condition documented at both ends, and the download retrieved at delivery so the record exists before anyone needs it.
One Trailer, One Set Point, Unless It Is Built for Two
A standard 53-foot reefer runs a single set point across the whole box, so everything inside lives at the same temperature. Multi-temp trailers split the space with movable bulkheads and a second evaporator to run two or three zones, which lets frozen and chilled ride together at the cost of pallet positions and a much smaller carrier pool. Size behaves differently here too: insulated walls, the duct floor and the unit itself eat into both cube and payload, so a 53-foot reefer carries less weight than a 53-foot dry van against the same 80,000 pound federal gross limit. And a partial shares the trailer with someone else's freight, so the set points have to be compatible. Produce at 34°F and frozen at 0°F do not ride together in a single-temp box.
What We Confirm With You in Writing
Three cold chain questions whose answer depends on your commodity and your receiver, so we settle them on the first call instead of publishing a promise that may not match your load:
- The temperature record format your receiver or your quality group will accept, since that rule is set by your customer, not by a carrier.
- What the assigned carrier's unit and procedures can document for validated pharmaceutical or life-science shipments, confirmed before booking rather than assumed from the equipment type.
- Wash-out and last-three-commodities documentation for food-grade loads, confirmed on the specific trailer assigned to your lane.
Frequently Asked Questions
What temperature should my load run at?
The commodity decides, and colder is not automatically safer. Frozen runs 0°F or below, fresh meat 28 to 32°F, dairy and most produce 34 to 38°F, pharmaceutical cold chain 2 to 8°C. Bananas, avocados and tomatoes take chilling injury below roughly 50 to 55°F, so a well-meant 34°F set point damages them. Send the spec your customer enforces and the load is booked to that number.
Can I ship cold freight in a dry van with ice?
No. Ice and gel packs cool but do not control: no set point, no forced airflow through the load, no temperature record, so a receiver asking for the history gets nothing. Melt also wets cartons that were not built for it, and dry ice releases carbon dioxide inside a closed van, a hazard for whoever opens the doors. If ambient works, ship dry van. If it does not, ship refrigerated.
Continuous or cycle: which should I ask for?
Continuous when the product respires or the band is tight, which covers most fresh produce, floral and anything pharmaceutical. Cycle is acceptable for solidly frozen freight with the thermal mass to ride out the off periods, and it saves fuel. Carriers default to cycle unless the load says otherwise, so put the run mode on the dispatch in writing.
Do I need the trailer precooled if my product is already cold?
Yes. A trailer that has been closed in the sun can sit well over 100°F inside, and the unit's job in transit is to hold temperature, not to fight the box and the product at the same time. Precool to set point, then shut the unit off during loading so it is not pulling humid dock air across the coil and frosting it.
What is a reefer download and when should I ask for it?
It is the temperature log the unit records on itself: set point, supply and return air, defrost cycles and unit on and off events, time-stamped across the trip. Ask for it at delivery, while the trailer is still at the dock, because units overwrite older data as memory fills. With the pulp temperatures at both ends, that log is the claim.
Can you move refrigerated freight into Mexico?
Yes, and the border is home field. Dobie is based in the Rio Grande Valley, and the crossings, the customs brokers and the Mexico-side carriers are weekly business. The reefer difference is the wait: the unit runs while the trailer stages, doors can open for inspection, the tractor changes hands. Fuel, run mode and set point margin get planned around that instead of assumed.
Last reviewed: August 2026 · Reviewed by the Dobie Transport logistics team
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