Time of harvest
The decision on when to harvest fruit is based on its stage of maturity. If fruit are harvested when immature, they will not have the right taste and aroma; if left on the tree too long, they soften and may develop a greasy skin.
The orchardist carefully monitors fruit maturity, looking at skin colour, flesh firmness, and soluble solids and starch breakdown patterns, as shown by the starch–iodine reaction on a transverse section of the fruit. Each cultivar has its own optimum values for these factors, which give the best cool-storage life.
Most cultivars are selectively harvested over two to three weeks, with each pick removing the most optimally mature fruit. European pears are normally harvested in a once-over pick.
Picking and packing
The apple-picking season lasts several months, as each cultivar becomes ready for harvest. Export harvesting may begin with Cox’s Orange Pippin in February and finish in April with Granny Smith. Apples and pears are picked by hand, usually into bags slung across the picker’s chest. The fruit is emptied into larger wooden bulk bins, holding around 400 kilograms, which are quickly moved to a cool store or a grading shed. Apples are usually dumped in water and floated off to be cleaned and graded. They are graded for freedom from visible defects, usually by human eye on a grading table, then pass under electronic colour sorters and weigh cells before passing onto separate lanes for packing. Fruit are normally packed into cardboard boxes on fibre trays for protection during transport.
Pears are not normally dumped in water, as they do not float. Instead they are removed from the smaller pear bins by hand then placed on the grader. Pears are usually packed in small, two-layer cartons, which hold around 7.5 kilograms.
Storage and transport
To preserve the fruit quality, apples and pears are stored in cool stores – European pears at -0.5°C, most apples at 0.5°C, and Asian pears (nashi) at 1°C. To slow the maturation processes even further, oxygen and carbon dioxide are carefully regulated in controlled-atmosphere (CA) storage. Typical gas concentrations are 1% oxygen and 1–2% carbon dioxide, the latter depending on the cultivar. Once fruit has cooled, it needs to be kept at these low temperatures even during shipping. Traditionally, apples were sent from New Zealand to overseas markets in the bulk holds of reefer ships, where the temperature was carefully controlled. More fruit is now being despatched in containers, some of which have CA facilities.