Keep it cool

Controlled atmosphere storage is vital to prolong the selling season for many horticultural crops, but not all post-harvest facilities make the best possible use of the technology, believes Jason Anderson of Hort Air Services.
"CA storage won't improve the quality of fruit. If it's in poor condition when it goes into storage, it will be in poor condition when it comes out. CA storage should be reserved for only the best quality fruit," said Jason who has 18 years experience in the kiwifruit post-harvest industry.
Facilities which gained the best from their CA stores were those that selected fruit carefully based on previous storage history and the condition of the fruit at the time of harvest, he said. Fruit or vegetables (and even flower bulbs) placed in a controlled atmosphere store are subjected to low oxygen and/or high carbon dioxide atmospheres which are artificially controlled.
"The atmosphere within a CA store won't support human life and no one must enter when it's in operation," said Jason. For that reason the atmosphere must be measured and controlled externally and Hort Air Services supplies equipment to do just that, including portable nitrogen generators and ethylene and CO2 scrubbers, portable analysers and automatic control systems.
"Many post-harvest facilities hire the nitrogen generators for the time they operate the CA stores and, fortunately for me, the apple stores have finished using them around the time demand picks up within the kiwifruit industry."
Although apple and kiwifruit CA stores are generally on a large scale, Jason also has equipment available for smaller producers of crops such as blueberries and strawberries.
"We can set up a tent system (within an existing building) to create a controlled atmosphere around just a few pallets of fruit. What it does is extend the shelf life and means growers aren't forced to process or freeze excess fruit, but can store it for longer and sell it fresh," he said.
Jason founded Hort Air Services in 2006 after 14 years working in the kiwifruit post harvest industry, including managing and helping design CA stores.
Hort Air Services distributes equipment designed and manufactured by the French company Absoger, which specialises in controlled atmosphere and associated storage equipment.
The company also imports and sells the EASI-1 ethylene analyser, manufactured by Absoger of France. "This device is a world-first in ethylene sampling and has significant potential for the kiwifruit industry in particular. Currently ethylene in the atmosphere of coolstores or CA stores has to be sampled and then tested in a laboratory, often leading to a time delay in getting results and the risk the sample may deteriorate," he said. "With the EASI-1, samples can be taken on the spot," he said.
Ethylene is a plant hormone produced by trees, plants fruit and vegetables in response to stress, and as they ripen and mature. Too much ethylene in a coolstore can cause the unwanted ripening of fruit so it is important for coolstore and Controlled Atmosphere (CA) store operators to monitor ethylene levels closely so they are aware of the condition of the fruit.
It is the nanoporous gold senor technology which gives the EASI-1 its extraordinary sensitivity to ethylene at levels as low as 10ppb in the air. The device can also be fitted with CO2, O2 or 1-MCP sensors, making it a portable, multi-function analyser.
Jason said Zespri was conducting trials with two EASI-1 analysers he has supplied.
"A number of kiwifruit post harvest operators have also shown interest and are awaiting the outcome of the Zespri trials," he said.
"For post harvest operators and coolstores, the EASI-1 mobile ethylene sampling service will save costs and time.
"Because the analysis is carried out on site it eliminates courier costs of getting samples to laboratories and reduces the risk of sample contamination because fruit samples do not have to be transported to be tested."