An Overview of Potential Pre-harvest, Harvest and Postharvest Methods to Maximise Organic Apple Quality

Prange, R.K., Braun, P.G., and DeLong, J.M.
AAFC-Atlantic Food and Horticulture Res. Centre, Kentville, NS, Canada

During the pre-harvest period the quality of organic apples will be influenced primarily by successful control of insect and fungal damage, e.g. use of scab-resistant apple cultivars, proper crop load and maintenance of proper mineral nutrition, especially nitrogen and calcium. During the harvest stage, lack of residual fungicides in organic production means that extra care must be taken to control postharvest decay by eliminating all fruit that have skin damage and avoiding postharvest dipping. Immediately after harvest, the use of hot water treatment (HWT) of ca. 53 °C for 2-3 min has been reported to reduce postharvest decay without negative quality effects. The most appropriate organically-acceptable storage technology is Controlled Atmosphere (CA) storage. It is a known technology that maintains quality as well as reduces decay and/or reduces the use of insect and disorder-controlling chemicals.

Results will be presented showing how low O2 - CA storage using HarvestWatch, a chlorophyll fluorescence-based technology, maintains apple quality without the use of any postharvest fungicidal or superficial scald-controlling chemicals.

The most serious storage problem for organic apples is postharvest decay. Organically-acceptable postharvest decay control will depend on the introduction of effective bio-pesticides. Data will be presented on a new bio-fumigant, Muscodor albus, which appears to be effective in killing postharvest fungal and bacterial pathogens of apples.

More research is needed using combinations of various methods since most potential methods may not be 100% effective when used alone.