Proper cold chain handling is a complicated process. It becomes even more complex when refrigerated containers are unloaded from ocean vessels and transported across the country by truck. Maintaining the cold chain involves several variables. Many things can go wrong, including vessel delays and port closures caused by fog, hurricanes and other weather disruptions. Trucks can wait in long lines for product pickup and experience other disruptions.

Because of produce’s perishability, there’s a keen sense of urgency and much room for error. Proper execution plays a vital role, say logistics experts. Changing consumer tastes and an astounding appetite for year-round availability of fresh fruits and vegetables are fueling increased product imports.

Containers must move from ports to receivers as fast as possible. Over-the-road carriers provide the industry speed and flexibility, says Henry Ware, office leader for the Richmond, VA, office of Cincinnati-based Total Quality Logistics. “They (truckers) are essential to the process,” he says. “Not only do they move the goods, they are the receivers’ eyes and ears on location. If there’s an issue, they are often the first person to report it.”

It Starts At The Port

When trucks rent chassis trailers from ports for longer hauls, the carrier should inspect the equipment’s condition to reduce the likelihood of any issues, says Ware. “The carrier assumes responsibility for the safety and speed of the load,” he says. Long loading times can affect hours of service rules. Port congestion and slow moving inspections are the primary causes of this. “It is his/her responsibility to deliver it to the receiver on-time,” says Ware. “Transportation over-the-road is similar to other produce loads once it leaves the port. Containers may be inspected and released quickly in some cases, but in others they could take several days. A container can be placed on hold, which is an additional delay in leaving the port.”

At the port, to properly maintain the cold chain, refrigerated container units must remain powered and temperatures must be maintained, says Amy Childress, vice president of marketing for St. Louis-based Emerson Cargo Solutions. Correct temperature ranges must be set during loading at ports and communicated before and during transit. If that doesn’t happen, product degradation becomes obvious upon load arrival. Product that wasn’t precooled to remove field heat could deteriorate through condensation.

As it is sometimes difficult to pinpoint causes of breakdowns, monitoring devices are important throughout the container’s movement on the ocean and in the trucks. Information is sent via modem to the ship and communicated to a cloud portal. In the United States, forward-thinking retailers are increasingly using independent temperature monitoring devices to ensure optimum product quality and safety, says Childress.

The containers’ interior, on trucks or ships, resembles a mini building with many temperature variations. “It is like facility monitoring on wheels,” says Childress. “In the past, people relied on temperatures downloaded from the reefers. But that doesn’t necessarily dictate what’s happening inside the container.” Improper loading can restrict airflow and will affect container temperature. Improperly calibrated reefers can be off by two to three degrees and can create issues. “People are starting to recognize more and more that you can’t necessarily rely on what the reefer temperature is telling you. It is what’s happening to the product that matters,” says Childress.

Communication is vital, according to Childress. Proper temperature ranges need to be communicated to truckers who must set reefer temperatures accordingly. If reefers are improperly set, truckers could be liable for product that was temperature-abused. Drivers sometimes place reefers in fuel saver mode, which is a bad practice when hauling temperature-sensitive cargo and can damage product, she says.

Insulation degradation in trailers that have been in service for 20 years can create hot spots. Pinwheeling or turning pallets sideways to create more space in the truck can also restrict airflow. If the sun is always shining on one side of a trailer, pallets on that side of the trailer may be more affected than the other side. Temperature abuse may not appear until several days later, says Childress.

Despite all the precautions taken at the port and on the highway, improper handling in cold storage and at the receiving end can also harm product quality. Proper temperatures must be maintained at retail distribution centers where product may be repackaged or placed on different pallets for individual store distribution, and in delivery. The same principles must be followed in the warehouse, says Emerson’s Childress. “Temperature mapping” provides data on what’s happening in different areas of the container or facility. The practice is done widely in pharmaceuticals to identify hot spots and temperature variations of more than 10 degrees.

An Orchestra Of A Process

Delays anywhere within the system can disrupt movement. Though a truck may be ready to load at the packinghouse, delays can occur, which could make a truck miss the vessel loading cutoff and delay shipment by an extra week. That could turn a 24- to 28-day trip into 31 to 35 days, which could cause serious product integrity issues, says Gary York, vice president of global sales and marketing for Eden Prairie, MN-based C.H. Robinson Worldwide Inc. An advantage of large logistics firms is their carrier relationships. They can work diligently with carriers and gain cargo placement on ships even after loading deadlines, he says.

The process involves a lot of choreography and many moving parts, says York. Longer transit times make little room for error. “The longer the transit time, the longer the supply chain, the more orchestrated you need to be to ensure everything goes as planned so you don’t create a longer supply chain that could put the product in jeopardy,” he says. “We want to make sure that when vessels arrive, that orchestration occurs between the carriers, our customers, the brokerage services and port operations. That seamlessness allows drayage carriers (truckers) to pick up the container and deliver to the customer in the most efficient manner possible.”

Changes in ocean shipping companies can also affect movement. The acceleration of mergers among large ocean carriers changes the lanes many carriers travel, which could alter transit times. Other carriers have gone out of business, which has caused confusion, limited shipping options and made logistics even more difficult to manage, explains York.

More ports are opening cold storage facilities, which can help during surges in holiday and seasonal demand. Dan Vache, sales director of FreightFlow, a Reno, NV, supply chain analytics company that helps users be more efficient, says the ports are installing more refrigeration for unloading. Cross-docking, which allows retailers buying direct to break down product and ship to different distribution centers, is also increasing at ports.

Expanding Port Cold Storage

Large cold storage operators who handle frozen storage are constructing fresh storage facilities. “Now, with the high volume of fresh coming in, they realize they can be a key to this by having cold storage facilities close to the ports, which is an opportunity to help our industry and help with distribution,” says Vache. Such operators may place containers in cold storage for the product’s owner and disperse in different manners so the client can ship mix loads of products.

Holds placed by the U.S. Department of Agriculture, the Department of Homeland Security and Customs and Border Protection, as well as the Food and Drug Administration can cause major delays. In June 2017, Gary Campisi, senior director of quality control in the Fresh Food Division of Bentonville, AR-based Wal-Mart, spoke about handling imported product at the second yearly Cold Chain Council meeting in Chicago. “Cold storage is a critical element,” he says. Wal-Mart does a lot of its own importing. Once product is unloaded from containers at ports, it’s crucial to immediately store product at proper temperatures.

Port operational hours can be challenging. As many ports are closed on weekends, containers need to be set out and picked up on Fridays. “It’s a challenge to get all these containers arranged and put somewhere and monitored for cold chain so the product can be delivered on the days that we want them,” says Campisi. “We can’t just fill a whole warehouse with bananas when we don’t have the capacity to put them into ripening rooms. Planning for that and getting them on the trailers and getting them delivered at the right time is critical.”

The Dilemma Of Mixed Loads

The transport of product, particularly mixed commodities of tropicals, in different temperatures can be problematic, says Campisi. Tropicals are becoming more important and in higher demand. Blueberries, grapes and other Southern Hemisphere fruit are shipped in temperatures of 34 degrees. Mangos, on the other hand, require warmer temperatures than most other perishable items. Though multi-temperature trailers can transport consolidated loads, such shipments aren’t efficient, and are in lower availability and smaller capacity than conventional trailers. The multi-temperature trucks are an alternative but not a positive one, says Campisi.

The challenge for the industry is finding compatibility, he says. It would be costly and inefficient for retailers to run individual trucks to all the chain’s distribution centers. The industry could manage the problem through product packaging or by employing companies that provide quilts to protect in-transit pallets, but that could create additional costs.

As an example, an Ohio retailer needs four pallets of mangos and two pallets of papayas in its distribution center while another retailer 20 miles down the road requests the same volume. Consolidated shipments could be an answer. The industry needs to determine how to maintain simultaneous efficiency, quality and freshness, says Campisi. Retailers require on-time deliveries, as well as proper volume to begin the ripening process. “It’s all about bringing in on-time the right quantity at the right temperature so we can start the ripening process right away,” he says. “The answer is somewhere, but we have to become very creative in how we will solve this problem.”

Temperature management to preserve product quality is the biggest issue in transporting imported produce, says Barbara Pratt, North America director of refrigerated technical operations for Maersk and a board member of the International Refrigerated Transportation Association, which is part of the Global Cold Chain Alliance.

After temperature is maintained during shipment, some commodities benefit from controlled atmosphere, dehumidification to minimize excess moisture and ethylene control, she says. “It is a continuous education process,” says Pratt. “Not just on the technology, but also how inlands (the transport of goods once they leave port to offshore facilities) are handled, what happens in the terminals and on the vessels, and how it all fits together for successful shipments.”