April 4, 2019
transportation report | Air Freight

Keep your cool

Keep your cool

Shipping perishable products by air? Here are five steps shippers can take to help ensure proper temperatures throughout the journey.

By Toby Gooley

Long ago, fresh produce, meats, and seafood were available only during certain seasons and within a comparatively short distance of where they were grown and harvested. Then came advances in packaging, refrigeration, and transportation, which allowed, for example, railroads to carry oysters from the Chesapeake Bay to St. Louis, and trucks to deliver vegetables from California's Central Valley to Minneapolis at certain times of the year. Today, consumers expect to buy their favorite fresh products—fresh blueberries, lobsters, roses, and much more—all year 'round.

For perishables with a short shelf life, shipping by air—by far the fastest mode of transportation—has become the preferred way to go. And it may be tempting to think that an aircraft's flight time is all shippers need to worry about when it comes to ensuring freshness. But maintaining the proper temperature throughout the shipment's journey, from pickup at origin to delivery at the destination, is the real key to ensuring freshness and quality. Here are five steps shippers can take to help their perishable products maintain temperature integrity and reach consumers in peak condition.

1. Know your temperature requirements. Different temperature ranges are acceptable for different product categories, such as meats and seafood, fruits and vegetables, and flowers. Frozen products, for instance, may have to be kept at temps below 0 degrees F, while fresh flowers, seafood, vegetables, and fruits typically travel at temperatures between 36 and 46 degrees, according to Air France KLM Martinair (AFKLM) Cargo. Some less-sensitive produce, such as asparagus, pineapples, and avocadoes, may only require protection from extreme temperature variations, the airlines say.

Some airlines offer services that include temperature settings specified by the shipper, while others only offer space in a limited number of temperature ranges, which may not exactly match the desired temperature for a particular product, says Emma Wen, perishable export operations leader, New York and Miami, for international freight forwarder Apex Logistics International. That is not necessarily a problem, because most perishable products have a temperature tolerance that allows slight variances, she notes. In addition, the right packing techniques can ensure proper temps are maintained even if the ambient temperature is a little higher or lower than the ideal. Which temperature range would be appropriate for a given shipment, however, is always the shipper's decision. As Wen says, "They know their commodities best."

2. Keep logistics partners well informed. Many hands (and handoffs) are involved in any air shipment. This can vary with the commodity, but in addition to the shipper and the airline, they may include a freight forwarder at the origin, a customs broker at the destination, and motor carriers and warehouses on both ends. All play a role in maintaining temperature integrity, so it's critical that they be fully informed of the shipment details. That includes the usual information, such as shipper, consignee, commodity, origin, destination, weights, and dimensions, of course. But each party that touches the shipment must also be aware of what temperature is required, whether any variance is allowed, and whether any special handling is needed before, during, or after the flight. Documentation—including shipment labeling and marking—that makes temperature and special handling requirements both clear and obvious is important too.

Shippers should also be sure to tell their freight forwarders what time constraints apply. "We need to know what the maximum allowable total transit time is so we can help the shipper find a suitable flight," Wen says. "That will help us decide whether a transfer will be OK or if it must be a direct flight."

3. Take care in handling products before and after the flight. It's important that everyone who handles perishables shipments understand not only the handling requirements but also the consequences of failing to adhere to them. Good sources of information include the Hazard Analysis and Critical Control Points (HACCP) international best-practices standard and the rules implementing the U.S. Food Safety Modernization Act (FSMA). Both are designed to reduce food-safety risk and include standards for safe handling, transportation, and distribution of perishable foods. The International Air Transport Association (IATA), which represents most of the world's airlines, publishes perishable cargo regulations that set standards for temperature ranges, packaging, marking, documenting, and handling of temperature-sensitive air cargo. 

Wen of Apex Logistics suggests paying special attention to the trucking leg of the journey. A refrigerated truck is a must, of course, but the motor carrier and its equipment should also be reliable and its service consistent, she says. She and her colleagues take nothing for granted; most of the perishables exports her group handles are live seafood and delicate fruits like cherries, so they always send someone to the airline to accept the cargo and tender it to the airline, both for quality assurance and to ensure compliance with Transportation Security Administration (TSA) rules, she says. For any temperature-sensitive shipment, it's important to verify that it arrived in good condition, with no visible damage that could compromise temperature integrity, she adds.

4. Think "total time in transit" when scheduling and packing shipments. Shippers only see a perishable product when it's in their possession, but that's just one segment of an air shipment's journey. Once a product leaves the premises, the maximum-transit-time clock starts ticking. It pays to be aware of how many handoffs there will be, how long a shipment will be in transit or held at various waypoints, and whether it will remain refrigerated the entire time. That knowledge will inform how items are packed; the longer the total transit time, the more cold packs and layers of insulation will be needed, for instance.

For some delicate or highly temperature-sensitive products like live seafood or cut flowers, the countdown begins when they are placed in shipping cartons. To avoid compromising a product's shelf life, experts caution against packing such items too far in advance of the flight's departure time and cutoff for receiving cargo.

5. Pay attention to packaging, containers, and protective coverings. This is a topic that could easily merit an article of its own, and it's impossible to discuss the many different packaging and packing options and best practices here. Careful research is called for, but here are a few basic considerations to keep in mind:

  • The basic principle is to prevent heat transfer. Materials in common use today for small containers include rigid polyurethane foam, reflective materials like radiant barrier films, and expanded polystyrene (EPS) foam. Gel packs and sealed coolant packs are popular for refrigerated products, while dry ice is often used for frozen items. (Note that dry ice is a regulated hazardous material and must comply with IATA requirements for documentation, classification, and labeling.)

  • Packaging and perishables experts at freight forwarders, airlines, and parcel carriers stand ready to help shippers understand their options and make appropriate choices, but it's the shipper's responsibility (or that of its designated packing house) to properly package and pack its products to maintain temperature integrity and prevent damage from melting or leakage.

  • Parcel carriers like FedEx Express, UPS, and DHL offer tips and general instructions for packing perishables as well as guides to different packaging options for temperature-controlled shipments on their websites.

  • Many airlines and parcel carriers offer special services dedicated to perishables and temperature-controlled shipping, including their own refrigerated storage and handling facilities. There's a lot to choose from out there, but just a few examples include Lufthansa Cargo's extensive "Cool" product line, American Airlines' Cool Perishables services out of Miami, and FedEx's "Temp-Assure" portfolio of services. Some airfreight forwarders, such as Hellmann Perishable Logistics and Flagler Global Logistics, specialize in temperature-controlled shipments.

  • Air carriers also offer an array of temp-controlled shipping containers, including models that can handle palletized shipments, as well as protective thermal blankets, reflective film, and other equipment to help maintain temperature integrity. There are hundreds of possible examples, but just two are Emirates SkyCargo's "White Cover Advanced" protective polyethylene sheet for cooling during transportation and cold storage, and AFKLMP Cargo's "Kold Kart" container, a temperature-controlled transport dolly that delivers palletized air cargo to and from the door of an aircraft under constant refrigeration in hot climates.


Food and flowers are far from the only products that require controlled temperatures when traveling by air. Pharmaceuticals, chemicals and hazardous materials, biological samples and other life sciences materials, and even semiconductors are all part of the so-called cold chain. These and other temperature-sensitive air shipments are almost always high-value products, so mistakes can cost a shipper dearly.

As we've seen, the best way to ensure temperature integrity from pickup to delivery is to know your product, work closely with perishable freight specialists at carriers and freight forwarders, be cognizant of time constraints and handoffs among cold chain participants, and use proper packaging. If there's ever been a freight segment where the old chestnut about an ounce of prevention's being worth a pound of cure holds true, it's perishable air shipments.

About the Author

Toby Gooley
Contributing Editor
Contributing Editor Toby Gooley is a freelance writer and editor specializing in supply chain, logistics, material handling, and international trade. She previously was Senior Editor at DC VELOCITY and Editor of DCV's sister publication, CSCMP's Supply Chain Quarterly. Prior to joining AGiLE Business Media in 2007, she spent 20 years at Logistics Management magazine as Managing Editor and Senior Editor covering international trade and transportation. Prior to that she was an export traffic manager for 10 years. She holds a B.A. in Asian Studies from Cornell University.

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