Keeping Cold Freight COLD With Changing Weather Conditions

Posted by Harriet Mills on Oct 29, 2021 3:49:55 PM

cold chain graphicThis is the time of year when temperatures across the country widely vary. Higher elevations are already snow-covered while areas of the East Coast can still be in the eighty-degree range like they were just a week ago.

For any given cross-country shipment, the ambient temperature outside the trailer during the spring and fall months can go through multiple changes along the route. If the reefer unit has not been regularly serviced or the trailer is in disrepair with leaks or holes, the safety of the cargo may be in jeopardy. 

It is during these months of unpredictable weather swings that shippers with temperature-controlled freight need to pay close attention to best practices and use extra vigilance in maintaining their cold chain.  

What precautions do carriers exercise in varying conditions? We asked some drivers and owner-operators to weigh in on what they do to ensure their cargo doesn’t go off-temp.

  • Keep a bulkhead on the trailer and in use, especially with multi-stop deliveries.
  • Be sure to run on continuous and not on start/stop mode. Most reefer failures occur at startup, so running 'continuous' can help avoid that problem. Older trailers have a hard time maintaining the required temperature, so make sure you don’t have any leaks in the reefer trailer, especially if you are hauling sub-zero loads.
  • Also, plug any drain holes and use a pulp thermometer back hatch.
  • Make sure door seals are fully intact. You can’t have any broken or missing gaps in the door seals. The cold air from inside the trailer will create condensation and leak through those same floor holds, which can degrade or erode the insulation on the underside of the trailer floor.
  • Service the trailer regularly by checking belts and making sure the compressor is working correctly. If you are running an older reefer and can afford to buy a new one, do it. It is a good investment!
  • Always carry spare oil and antifreeze for the trailer’s reefer engine and radiator.
  • In fear of stating the obvious, don’t run the reefer very long while the doors are open when it is hot outside.


What precautions do 3PLs take to ensure temperature maintenance: At Choptank Transport, we follow strict shipping guidelines for our cold freight services. These are called SOPs, or standard operating procedures, and every person who has a stake in the shipment must follow these steps judiciously. Below are a few of the primary steps we follow when working with refrigerated freight shippers on temperature-controlled shipments.

Step 1: Establishing the specific temperature range for the product is first and foremost. This information must be communicated in several ways – verbally and in writing. It must be accurately documented on all paperwork, including the bill of lading (BOL) and any communication between shipper and carrier sales/dispatcher. Important: There is no such thing as over-communicating when it comes to shipping temperature-sensitive freight.

Step 2: In addition to getting verification that the carrier’s trailer is dry, clean, and odor-free, the trailer must be adequately pre-cooled to the required temperature by the shipper. In extremely high heat zones, this may take longer than in cooler climates. It should also be documented and verified that the trailer temperatures run continuously, without interruption.

Step 3: Upon request or if the product is suspect, we will probe or pulp a product on the loading dock before putting it in the reefer trailer. This practice is particularly important for some kinds of produce that may come out of the fields hot. It is then re-probed upon arrival before the load is accepted at the receiving dock. The job of the reefer trailer isn’t to cool down a product but to maintain a certain temperature. If melons load at 85 degrees and you put them into a pre-cooled trailer at 45 degrees, they will probably explode. (Most produce is cooled with forced air before shipping.)

Step 4: Tracking is required by Choptank for all loads over 500 miles. Choptank requires its contracted carriers to download the Trucker Tools app, industry-specific software that allows us to know where our customer’s freight is at any given time. To record temperatures, we use temp tail recorders to monitor and document real-time readings en route. We receive e-mail or text alerts whenever there is a temperature fluctuation which allows us to address the issue right away.  

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There are multiple weather apps that truckers tend to favor. Here is a list of a few popular ones that are tried and true. 

Choptank Transport's customers have easy access to their own weather feature in Choptank's customer-facing portal ORBIT TI

Temperature-controlled transportation also keeps products from freezing as much as it keeps products from getting too warm and spoiling. There are many things that can go wrong between origin and destination, which is why it is important to work with a transportation provider that you trust.

In an excerpt from the USDA Handbook, Protecting Perishable Foods During Transport by Truck or Rail, the authors explain it further. 

Trucks transporting perishables through areas with outside temperatures much lower than 32°F (0°C) may need to be warmed rather than refrigerated to prevent freezing or chilling injury. Product freezing also may occur if the thermostat setting and/or low-temperature floor limit are too low, particularly on the top layer of trailers, the rear of the trailer when a ceiling air chute is installed, and the bottom layer of marine containers, where the coldest air exits the refrigeration unit. Chilling and freezing tend to occur in characteristic patterns within the load. The most serious chilling and freezing occur in the product that is exposed to the coldest air or is nearest to the walls and floor when the outside temperatures are extremely low. Sensitive products should not be allowed to directly contact the trailer or container walls or floor in order to avoid excessive heat transmission to the outside environment.

Here is a "chilling" fact. Did you know that a recent study determined that supply chains are responsible for 40% of food waste in North America? 

There are minimal temperature-related rejections at Choptank Transport because of the detailed SOPs, carrier vetting practices, and vigilant staff we have in place. From the acceptance of a tender to the final delivery, we are watching and monitoring every shipment.

Have some tips of your own to share with fellow shippers or carriers? Leave a comment below.maintain the cold chain-2


Tags: Shipper News, refrigerated freight services, frozen freight shipping