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Avocado supplier Avanza has completed a trial with Daikin Reefer using Active Controlled Atmosphere (CA) technology on a proof of concept shipment of 6,500 kg avocados between the ports of Tauranga, New Zealand, and Busan, Korea.
The trial took place in December, towards the end of the New Zealand avocado season, which runs from September to January.
By slowing down the ageing process that food and other sensitive, perishable products undergo during transit, the purpose of CA is to allow them to be transported in better condition for longer periods of time, extending shelf life.
Colin Partridge, technical manager and representative of Avanza, stated: “CA reefer technology is essential to our business as avocados are a high respiring cargo and need precise optimal atmosphere levels throughout transit to safeguard quality over long distances.
“As the only active, rather than passive system in the market, we wanted to trial Daikin’s Active CA technology to see if the benefits of an active system are genuine.”
Avanza are now discussing the use of Daikin’s system for next season’s shipments, he added.
Adapted from Daikin’s oxygen concentrator, which was developed for use in the medical industry, the Active CA system is based on vacuum pressure swing adsorption (VPSA), an active atmosphere separation technology that is meant to rapidly create the optimal CA.
VPSA uses the mineral adsorbent zeolite to capture a large quantity of nitrogen from the air and transfer it into the reefer container, allowing oxygen levels to be quickly reduced, without the need for additional nitrogen gas injection.
Unlike passive CA, which relies on produce respiration, Daikin’s Active CA delivers nitrogen rich gas to the reefer container with inbuilt equipment, reducing oxygen density rapidly.
This puts the fresh produce to “sleep” in a matter of a day or so, leading to longer shelf-life at the destination.
Ah Huat Goh, general manager, global marketing and service, Reefer Container Department at Daikin, said: “For produce such as avocados and apples, food scientists and growers alike understand the benefits of consistently low oxygen and low carbon dioxide settings during transit.
“Thanks to the positive inside pressure created by the nitrogen gas injection, which prevents the ambient air from entering the container, Daikin’s Active CA system can reliably maintain low O2 and CO2 levels. With Passive CA, the pressure inside the container is negative which makes it is easier for oxygen to ingress, especially as the box ages, potentially causing damage to cargo.”
For the Avanza trial, Daikin’s engineering team installed an Active CA “kit” onto a 20ft ZeSTIA unit which had been CA provisioned.
The ability to retrofit Active CA onto CA-provisioned units ensures that upgrading containers is quickly achievable.
According to the reefer manufacturer, its Active CA is also suitable for low respiring leafy vegetables and fruit such as grapes and berries that have been traditionally difficult to ship over long distances.