Shippers face many challenges when maintaining the cold chain for food transportation. Chill out! These solutions can help.
What’s the difference between a bowl of luscious strawberries and a bowl of moldy mush? It might come down to just a few degrees of temperature.
“The opportunity to get things wrong in maintaining the cold chain is quite significant,” says Jez Pile, director, enterprise food supply chain platforms at Telus Agriculture and Consumer Goods, based in Calgary, Alberta.
On the journey from producer to consumers—involving transportation, storage, loading, and unloading—temperature-sensitive produce passes through many points where handling errors could reduce quality and safety, says Pile, whose company’s products include a temperature monitoring system for fresh food.
“It’s all about minimizing the touches,” says Stu Kaminsky, owner of Agri Exotic Trading, a wholesale distributor of fresh produce in Clifton, New Jersey. “You pick up at the shipping point and then receive the product in your warehouse with close attention to the cold chain.”
Refrigerated processed foods and frozen foods face similar challenges. Each product needs to stay at the optimal temperature from origin to destination.
From Pre-Cooling to Unloading
The effort to preserve the cold chain starts even before a supplier loads food onto a refrigerated truck.
“The role of the reefer is not to cool the product, but to maintain the temperature,” says Jake McPaul, head of refrigerated operations and product in the Fresh Freight division of WARP, a Los Angeles-based third-party logistics (3PL) company and technology developer.
Pre-cooling is the supplier’s job, and this step is crucial. “When warmer product goes on a truck, that takes the shelf life right out of it,” says John Druckenmiller, general manager at Kool Logistics in Brentwood, Tennessee, which transports temperature-sensitive foods, including fresh and frozen and some refrigerated goods.
Kool Logistics drivers use “pulp thermometers” to check whether produce is sufficiently cooled before loading.
Refrigerated trailers or containers keep food properly cooled in transit. One challenge arises when a load includes products with different needs.
Take peppers, which should stay at about 42 degrees F. When they share a trailer with produce that’s happiest at 35 degrees, peppers need to bundle up for the ride.
“We have the shipper ‘paper’ the product,” says Druckenmiller. “It creates insulation, keeping the air flow from getting the product too cold.”
Technology that monitors temperature in transit also helps to maintain the cold chain. Telus Agriculture and Consumer Goods provides a thin, autonomous sensor tag that shippers attach to produce, often on the outside of cartons. The tag records the temperature of the product itself—not just the air at the rear of the trailer—every five to 15 minutes, creating a digital log.
“When product arrives at its destination, the data is automatically downloaded,” Pile says. A wireless gateway, operating on an open-source internet of things (IoT) network, captures the data when a tag comes within range. Telus’s system then checks the log to see if the temperature ever veered too far during the trip.
“If there are issues, our platform automatically notifies relevant stakeholders.” Pile says.
The tag can also tell if product was left too long in the wrong environment during loading or unloading. And the platform can aggregate and analyze data from many shipments, using artificial intelligence (AI) to spot weak links in the cold chain so the shipper can correct them.
While some monitoring systems provide a temperature log at the end of a trip, others trigger action in real time.
“We can ping the driver and say, ‘At your next stop, document the temperature in your reefer and upload it here,’” says McPaul. “The driver will take a photo of the reefer’s temperature display and use WARP’s solution to provide it to the shipper.”
Some tracking systems built into reefers transmit alerts when things go wrong. “If the product goes above 37 degrees [if that’s the top of the permissible range], we receive an alarm or an e-mail saying, ‘There’s a problem. Have the driver check the unit,’” Druckenmiller says.
When a driver can’t fix a malfunctioning reefer, the shipper or its 3PL might take other steps to rescue the load. “We can leverage our network of crossdocks,” says McPaul. “Hopefully there’s one close, and we can get the product off temporarily, maintain the temperature, and bring in a properly functioning unit to carry on the rest of the way.”
Unloading also poses problems for the cold chain. Even when the reefer keeps blowing cold air, and even when the loading dock is cooled, hot outdoor temperatures can take a toll if the transfer from truck to building takes too long.
Good communication between the driver and the unloading team can help. “We have optimized the process so drivers at the receiving end can use their web app or mobile app to notify our customer and us that they’ve been on a door for a while and this needs attention,” McPaul says.
Since it can take five or six hours to unload a trailer with a mix of products, it’s important to keep the dock cooled and keep a tight seal around the dock door. “If it’s 95 degrees out, the humidity created from the reefer unit blowing the cold air can create a real problem if the dock’s not properly cooled, or not refrigerated at all,” says Druckenmiller.
Training and Collaboration
To avoid problems during unloading, or other breaks in the cold chain, Agri Exotic relies on strong standard operating procedures (SOPs). “It’s a matter of training and making sure that everybody in the process is aware, respects the product, and knows how to handle it,” Kaminsky says.
Agri Exotic sources seasonal produce from around the world and distributes it to hotels, restaurants, and retail stores across the New York metropolitan area. Agri arranges for carriers to transport produce from its suppliers, and then it uses its own fleet of refrigerated trucks to deliver to customers.
Trailers that transport Agri’s products use analog devices called strip chart recorders to monitor the temperature. “Let’s say you have a three-day trip out of California,” Kaminsky says. “It plots every hour, and if it gets outside the correct temperature zone, there’s a problem.”
The recorder doesn’t transmit information in real time. But when the load arrives at Agri’s facility, workers check the log while also carefully examining the produce.
“Certain commodities are more prone to injury if it’s too cold or too hot,” Kaminsky says. If the log shows problems with the temperature in transit, employees in the warehouse give those products special scrutiny.
Agri divides its warehouse into several temperature zones to accommodate different products.
“Certain lettuces require 36 degrees, while summer squash requires 50 degrees, and a tomato requires 50-plus degrees with a different kind of humidity,” Kaminsky says. Employees check storage areas continuously to make sure each one maintains the right temperature.
Drivers check temperatures on Agri’s reefer trucks as they deliver orders to customers. The produce faces special challenges at delivery locations. “In the middle of the summer, if it’s 100 degrees out and the driver opens the back of the truck, the temperature will change,” Kaminsky says. “It’s important to close back up as soon as they get unloaded.”
Whatever the conditions, everyone involved in a delivery plays a part in protecting the product. “It’s a collaboration between whoever is receiving the product on our customer’s side and us,” Kaminsky says. “It’s a 24-hour process.”
Frozen Warehouse Shortage
For Bellisio Foods, a frozen food manufacturer based in Minneapolis, the biggest cold chain challenge of late has been a dearth of warehouse space. “There’s simply not enough of it in the United States to service the multitude of products that require frozen temperatures,” says Matthew Leuthold, the company’s logistics manager.
Capacity is especially tight in areas near the East and West Coast ports. “A lot of seafood is imported into the United States and consumes a lot of that space,” Leuthold says. “And then ice cream is a massive consumer of that warehouse space.”
Bellisio produces frozen foods under brand names such as Michelina’s, Boston Market, Atkins, and White Castle; it also provides contract manufacturing. From production facilities in Jackson and Archbold, Ohio and Vernon, California, it ships product to the distribution centers of virtually every retail chain in the country that sells groceries.
Bellisio has avoided the worst of the warehouse crunch because, just before the pandemic distorted supply chains around the world, it finished building a large, automated frozen warehouse at the Jackson facility. The goal was to handle anticipated growth.
“Utilizing third-party warehousing can be quite expensive, especially when the market is very tight,” Leuthold says. “Rather than rely on what would be available in the marketplace, we thought it best to have our own facility.”
But Bellisio does rely on a third party—ODW Logistics of Columbus, Ohio—for efficient transportation.
“We utilize their optimization technology to take a multitude of less-than-truckload (LTL) orders and consolidate them into full truck orders,” Leuthold says. “This fills the gap in frozen transportation, where there aren’t reliable, true LTL carriers. We’ve leveraged their technology to make sure we’re building the best possible multistop loads for a truck to haul.”
Those frozen food carriers do a good job of maintaining the cold chain. “Most refrigerated equipment on the road has improved in terms of technology quite significantly in the last decade, with more efficient refrigeration, better real time monitoring of temperatures inside the trailer, and quicker adjustments to correct when things start to get out of line,” Leuthold says.
No matter how efficient those reefers are, though, they’re not cold enough for Dippin’ Dots, the cryogenically frozen beads of ice cream, yogurt, sherbet and flavored ice sold in amusement and retail locations throughout the U.S. Dippin’ Dots, based in Paducah, Kentucky, relies on dry ice and insulated packaging to keep its product at an ideal -40 F in transit.
The company manufactures in Paducah, flash freezing the beads at -320 F and then storing them in a freezer at -40. When it’s time to ship, workers pack the product with dry ice into cardboard boxes insulated with Styrofoam. Dippin’ Dots ships from distribution centers in Paducah and Lancaster, California.
How much dry ice goes into each box depends on how far the product will travel. “Sometimes we even ship all the way to Alaska or Hawaii from California, which will take 10 to 14 days,” says Doug Barwig, the company’s vice president of operations. Those shipments go by barge from California or Seattle.
Such long transits are especially challenging in summer. But Dippin’ Dots doesn’t use refrigerated transport. “We have found that the dry ice method works wonderfully,” Barwig says. Nor does the company monitor the product’s temperature en route.
Knowing how easily a delay could ruin the product, most carriers who handle the final-mile deliveries jump in to help if they get an e-mail saying that a shipment is running late.
“When a shipment is delayed on Friday for some reason, and they have someone working on Saturday, they’ll deliver it for us on Saturday without extra charges, ” Barwig says.
For most of its major accounts, such as movie theater chains and theme park companies, Dippin’ Dots provides freezers and delivers directly to the point of sale. Franchisees receive their product in wholesale quantities and distribute it to retail locations themselves.
“Dippin’ Dots franchisees buy extra dry ice from us so they can run those routes,” Barwig says. Some install generators to power freezers on their trucks, but there is a limit to how much product they can carry that way.
Insulation and dry ice also make it possible for Dippin’ Dots to sell online and ship directly to consumers.
While it takes precise planning and execution to deliver those frozen treats, it also takes coordination, communication, and suitable technology all along the cold chain to keep perishable foods in optimal condition for consumers to enjoy.
Fresh Del Monte Gets It Down Cold
Fresh Del Monte, a vertically integrated producer, distributor, and marketer of fresh and fresh-cut fruits and vegetables, has ordered 2,200 Daikin ZeSTIA cold chain units. Ten are fitted with Daikin’s controlled atmosphere technology.
Headquartered in Japan, Daikin Reefer supplies refrigeration and climate control solutions for freight containers.
Fresh Del Monte’s South American regional office acquired 1,700 of the units, which will be used on the busy trade between Central America and the United States, where the primary shipments are bananas and pineapples.
An additional 500 ZeSTIA units will be used during the 2022/2023 Chilean fruit season on the Chile-U.S. trade, carrying primarily grapes, apples, peaches, plums, and blueberries.
Prove It: Cold Chain Audit Checklist
Cold chain shippers and third-party logistics (3PL) providers understand the importance of visibility into temperature-controlled shipments from the point of origin to final delivery. A documented audit of data collected by temperature loggers throughout a cold chain shipment’s journey is the best way to share that visibility with your supply chain partners.
There’s much to track regarding cold chain management and the handling, transportation, and distribution of temperature-controlled food. Tive, a provider of cold chain temperature tracking solutions, offers the following checklist to help you prepare for a cold chain audit. Some of these items pertain directly to shippers, while others are for your supply chain partners. Sharing this checklist with them ensures they can be ready for an audit, as well.
- Collaborate with 3PL and carrier partners to implement written procedures regarding temperature handling and sanitation practices.
- Use a data logger to record data related to temperature- sensitive products, and be sure its placed correctly.
- Ensure temperature measuring equipment is correctly calibrated and recorded.
- Ensure in-transit and storage temperatures remain in the acceptable range, and are recorded appropriately.
- Create and maintain a repository of temperature profiles for past loads.
- Ensure proper segregation of raw foods and ready-to-eat foods. Maintain records of all invoices and shipper-to-carrier agreements for at least 12 months.
- Develop processes to manage temperature variations that may occur during loading and unloading.
- Ensure drivers and warehouse personnel receive thorough training regarding refrigeration units and loading/ unloading processes for temperature-sensitive foods.
- Upon delivery, ensure any affected cold chain items are quarantined and discarded to prevent unsafe products from reaching consumers.
- Report any incidents of temperature excursions to the manufacturer and other supply chain stakeholders as soon as possible.
- Ensure all supply chain partners—including suppliers, warehouse personnel, and carriers—can assure the integrity of the cold chain throughout transport.