Controlled atmosphere (CA) is nothing new for the produce industry, but Denmark's Maersk Container Industry (MCI) believes the release of a new patented CA technology could forge greater connectivity for more isolated fruit growers and consumers. MCI head of research and development Gert Jorgenssen says part of the benefit lies in an extremely thin membrane in the container that seperates carbon dioxide from nitrogen and oxygen, allowing for longer fruit shelf life.

Time has always been a determining factor in the effectiveness of transporting fruit, with the development of sugars or oils bringing the food closer to an ideal state for consumption, before wasting away through fermentation and putrification.

The development of efficient railroads alongside banana plantations in Latin America spurred a previously unimaginable trade in tropical fruit in the late 1800s, followed up by the wide dissemination of refrigeration and eventually controlled atmosphere as we know it today.

Players across the supply chain are constantly striving to take produce the extra mile and have it last the journey, and MCI's Cool Star CA has been able to do that, making new fruit trade routes not so impossible anymore.

For example, Jorgenssen says the technology has lengthened the travel time of bananas from 30 to 45 days, opening up trade between places like Ecuador and Azerbaijan, or connecting Mozambican fruit with Europe and Asia.

"We've had it in operation for about four years, however the first three years it has been exclusively with Maersk Line in a kind of extended test period, but now we have gone out to broader publicity with the product," he told www.freshfruitportal.com.

"Once fruits are cut from the tree and put in the container, they will eat the oxygen and produce CO2. We then lower the oxygen, and we raise the level of CO2, and we keep that constant.

"The technology as such is not new but before it has not been possible to have it as a low cost product in a container."

He says the control occurs with the help of a vacuum pump that removes the carbon dioxide through the CA membrane, and the process is accompanied by a mechanism that sets the ideal level of fresh air intake for the fruit.

Click here for a video on how the technology works.

"This membrane we are using to separate the air, as easy as it sounds, is quite a complicated matter. The thickness of the membrane is down to one thousandth of a millimeter - to manufacture something down in that very thin layer, that took about four to five years to develop.

"The whole membrane, because it’s so thin this active layer, you can’t leave it alone. It will just disappear almost in the air, so we have to put it on something else, so there are seven other supportive layers made from various products."

Distant markets, distant fields

The containers expert highlights great potential for the technology in opening up new possibilities for isolated growers who are currently limited by a lack of controlled atmosphere or cold chain facilities.

"Banana is the biggest commodity worldwide that is moved in refrigerated transport; the volume is just enormous. One example, in India they grow what is equivalent to half a million containers full of bananas per year, so they are sitting on about 20% of the bananas grown worldwide.

"But each year, they only enter about 1% of the world export market - that's not not only due to the lack of a cold chain an CA facilities, but it’s also because they don’t have the time to reach the coast to be shipped from the inland.

"From inland India or China to the markets, time is critical and CA can help you with that issue by extending the time. CA is an advantage where you have distant markets or different growing fields.

The membrane is designed for horticultural goods with high respiration rates like bananas and avocados; CA can extend the latter's shelf life by 50%, according to Jorgenssen.

"All foods respire in the same way. It's all about removing the CO2, so we actually have to make the membrane for the highest respiring product, and by doing so we are also able to cater for some of the lower respiring products.

"Not all products are as receptive to CA but bananas and avocados are very receptive to it. Some fruits like pineapples are not so sensitive, but others like mangoes and asparagus are."

On a personal note, Jorgenssen is hopeful the technology will improve the availability of better tasting mangoes for consumers like himself.

"I’m not an expert in mangoes, but I know that in places like India they have very tasty and interesting varieties of mangoes. In Europe though, for example here at the supermarket in Denmark, I can only find boring mangoes like Tommy Atkins.

"They have a longer shelf life than most of the other mangoes and they are grown closer to the market here. It would open up some possibilities if you could transport other varieties, better tasting mangoes, to Europe; I would very much welcome that."

He also touts the benefits of CA in transporting asparagus.

"Asparagus is quite a large commodity and its also an interesting commodity because after you have cut it, it continues to grow.

"When it’s in transportation to Europe you put it in water and it continues to grow, and you don’t want to run it short of water, you don’t want it to grow too much.

"You want to restrict that a bit, and the way you can do that is by putting it in controlled atmosphere."

Photo: Maersk Line

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