When it comes to transporting produce, ship-born refrigerated containers have steadily gained the upper hand, with few notable exceptions. Some high-value fruits and vegetables such as blueberries, asparagus, avocados and mangoes still move at least in part by air. Then, there are cut flowers, where more than 90% of export trade is transported by air.
The fight for market share of these air-born goods continues. The arena is in part technology, but economics and geography play important roles as well. So, too, does psychology.

“I’m convinced that it’s technically possible, that there’s nothing to hold us back,” said Jeroen van der Hulst, managing director of Flower Watch Kenya, a research and consultancy firm advising the cut flower trade. But “it’s a very conservative industry. It’s difficult to drive changes.”

According to data compiled by Rabobank a year back, Colombia leads the field in ship-bound freight, exporting about 15% of its flowers by container, almost entirely to Europe. Other sea-bound flowers include those shipped from Vietnam to Japan and Israel to Europe.

Sea offers distinct cost advantages. Although rates vary widely, shipping flowers by sea can save anywhere from 25% to 50% over air. Environmental costs are far less as well.

While airfreight is obviously quicker, it isn’t necessarily safer for perishable cargo. The weakest link in airborne shipping is the tarmac, where a cargo can sit sometimes for several hours in the heat, waiting to be loaded onto a plane. With refrigerated containers, it’s possible to move cargo from the farm to the consumer without breaking the cold chain.

“Too many times, the weak link is on the tarmac, often with very high temperatures, when the flowers are being unloaded and from the warehouse to the aircraft,” said Sabastiaan Scholte, CEO of Jan de Rijk Logistics, based in Roosendaal, Holland. “Via sea freight, the cargo is always in an active cooling container,” said Scholte, who is also chairman of the Cool Chain Association. “With airfreight, there are too many temperature fluctuations when the product changes hands”

“With the right temperature controlled systems,” he said, speaking specifically of cut flowers, sea “can be a threat to airfreight.”

Technological advances linked to refrigerated containers with active temperature control assist in prolonging shelf life of perishables, by insuring the products remain fresh throughout the cold chain. These systems not only regulate temperature, but monitor oxygen, carbon dioxide levels and humidity. Some systems as well can expel ethylene, which quickens the ripening process in certain produce, especially bananas or mangoes.

But these kinds of technologies don’t necessarily benefit all perishables equally. “If you have apples, they will maintain themselves as apples. With flowers, you have stems, buds, flower-heads. You might also have several different varieties, roses, but also carnations or other flowers,” explained van der Hulst. “Flowers are very difficult to find the right recipe for controlling the atmosphere.”

While airfreight continues to dominate in these niche areas such as flowers, there are signs containers could make inroads. “I’m quite certain it will happen,” said van der Hulst. “I see the first signs.”

The question is how quickly.

“Research shows the sea container is the best refrigerated system in the world,” said Dr. George Staby, the co-founder of the Perishables Research Organization, who has been studying post-harvest floral crop handling for more than three decades. “I would have thought that sea container shipments of cut flowers would have got more traction by now.”

So, why hasn’t more of this high-value perishable cargo moved to sea? Flowers provide an interesting glimpse at the rationale.

For one, the trade in cut flowers is geared to quick transit. A plane from Bogota, Colombia to Miami takes 3 ½ hours. A ship from Cartagena, Colombia to Miami takes at least three days.

What’s more, if farms miss one plane, they know they can grab another. With container ships, there’s a much longer lead-time, and dependability can be lacking. While Colombia and Ecuador may have established sea lanes because of other exports, such as bananas, shipping from Kenya or Ethiopia can be spotty at best.

Then there’s the commodity itself. A container can hold 150,000 stems, or anywhere from eight to ten tons. Most importers just don’t order enough flowers in one go for a full container, unless perhaps in anticipation of Valentine’s Day. Most customers don’t want to accept and store a whole container’s worth, either.

“One consignee is usually not big enough to take the risk,” said Sanjay Savur, the Melbourne-based division head of atmosphere control system maker Maxtend.

That leaves consolidators. But mixing flowers can be tricky, especially since one big order can equate to dozens of separate varieties.

There’s a bit of chicken-and-egg at work as well. In the US, for example, air-related infrastructure is extremely well developed. Ports would have to play catch-up and spend significant resources on facilities. So, too, would the freight forwarders and importers.

When fuel prices shot up a few years back, the industry grew alarmed and “there was a huge push toward” the use of containers, said Christine Boldt, the executive vice president of the Association of Floral Importers of Florida, which represents most of America’s major flower importers. But because the cost of oil and gas has plummeted, that sense of urgency is no longer there, she said, even if the trade hasn’t benefited.

Controlled atmosphere technology and its use in refrigerated containers are nothing new. Mitsubishi Corp., for example, started selling the Australia-developed product Maxtend in 2001, and “we weren’t the pioneer,” said Savur.

The biggest advancement, Savor said, is that these systems now can fit into any standard reefer. Major systems providers such as Mitsubishi, Carrier and ThermoKing also are attempting to better and refine their products, adding new features as they cut down the cost.

“Any fresh commodity breathes, whether they are bananas or flowers,” explained James Taeckens, senior product manager for Carrier Transicold’s global container products. The object of these systems, he said, is “to slow the process down, slow down the oxygen, slow down the natural ripening process.”

Carrier Transicold recently announced that Hapag Lloyd had purchased 1,000 refrigerated containers equipped with the newest version of the controlled atmosphere system, called “XtendFresh.” These were being deployed to Latin America, according to the announcement, but were being cited for use in shipments of bananas and mangoes.

A few companies have the sights set on the opposite direction, and are attempting to assist airfreight with the broken cold chain. Kold Kart, for example, is a decade-old company, based in the Los Angeles suburb of Gardena, which makes what are called temperature-controlled dollies or tarmac vehicles. These look a bit like refrigerated containers on wheels and are designed to shuttle between warehouse and plane. Inside a refrigerated warehouse, perishable cargo is loaded into the dolly and then pulled planeside, where the cargo can be transferred to the cargo hold, without compromising the temperature. The Kold Kart dolly is equipped with the same kind of temperature control system as an advanced reefer. In fact, one model uses a Carrier Transicold system.

Airlines and shippers have been slow to adopt these dollies, as they add yet another level of cost. And, for the operations to work optimally, the dollies must be available on both sides of the flight, which means placement in far-flung locations.

But that resistance is slowly melting, according to Bryce Barler, Kold Kut’s director of operations. A number of airlines are beginning to use the system. He cited as well the big box discounter Costco, which ran tests comparing pallets of cargo that were transported with Kold Kut, against those that weren’t. “They saw a huge difference in the amount of losses and an increase in shelf life,” he said.

The biggest customers are those shipping berries and pharmaceuticals, Barler said. He added that shippers are beginning to use the dollies for cut flowers as well.