CA Storage

In 1967, Bill Montague and fellow Orchardist Jack Petty introduced Controlled Atmosphere Storage to Australia.

Contrary to what most consumers today think each and every apple tree grown around the world produces just one crop of apples each year. The southern hemisphere apple trees flower in September and early October and develop apples for a period of between 5 and 8 months after which the apples are ‘ripe’ for harvest. In Australia, growers use a number of pre harvest tests on apples to ensure they will be of optimum quality when they reach the retail shelf. The first commercial apple harvested each year is the Royal Gala. Harvest of this variety commences in mid to late January in the warmer climates and concludes in March in the cooler areas such as Tasmania. Following the harvest of Royal Gala orchardists move onto later varieties such as Red Delicious, Granny Smith,Fuji, Pink Lady and finally Sundowner which is harvested in late April and early May. Overall therefore apples inAustraliaare harvested over a 5 month period depending on variety.

Since apples are an annual crop but one that has good keeping qualities, cultures around the world have been ‘storing’ fruit for generations in order to enjoy the natural mineral and vitamin benefits provided by an apple throughout the year. The earliest storage of apples was undertaken in barrels which were placed under the ground in order to maintain a constant cool temperature which is critical for maintaining firm fruit.

In the 1950s work was completed on a new method of storing apples that was designed to enhance eating quality even further. Controlled atmosphere or (CA) storage was developed as a result of a large body of research conducted into the keeping quality of apples. This research found the natural ripening process of apples after harvest could be significantly slowed if the fruit could be stored in an atmosphere that was low in oxygen. As a result of this research specially sealed rooms were developed into which apples could be placed and then the oxygen removed to enhance the keeping quality of the fruit. Since the inception of CA storage the availability of apples that are firm and crisp has expanded dramatically.

In the late 1990s an additional technology was developed that further enhanced the keeping qualities of fruit in CA. This technology which is known as SMARTFRESH involves replacing oxygen in a cold room with a gas for a period of 24 hours immediately after harvest. This gas, which is non toxic and leaves no detectible residues, slows the ripening process allowing apples placed in CA storage to retain more crunch and flavor than fruit stored in conventional CA.

The result of both these storage innovations is that today in Australia consumers can enjoy Australian grown apples which are firm, juicy and Australian grown for 12 months of the year.

Alternatives to Storage of Apples:

There are very few alternatives to stored apples for a consumer who wants to enjoy apples year round. The reality of the matter is that mother nature designed the apples to be produced over a full 12 months thereby making it impossible for more than one crop to be harvested each year. Perhaps the only way one could extend the time during which fresh harvested fruit was available would be to import product from the northern hemisphere during the summer months. While this sounds sensible in theory the reality is that it is likely to take at least 30 days for an apple from a tree in China or the USA to reach a table in Australia. These apples while more recently harvested will still require storage of some description in order to ship them to Australia. Additionally these apples will need to be shipped across vast distances at high economic and environmental cost in order for them to be enjoyed in Australia. In a world where we want everything now the humble apple reminds us that mother nature doesn’t work that way.