Apples are placed in cold storage when they arrive at the packinghouse from the farm so that field heat can be removed as quickly as possible. Rapid removal of field heat has positive effects on both fruit quality and reduction in storage decay. Apples continue to breathe after they are picked from the tree, so postharvest cooling slows respiration and increases storage life. Apples take in oxygen and give off carbon dioxide while starches change to sugar in the fruit flesh (ripening).
Apple varieties differ in their conditions needed for proper storage. Researchers develop specific recommendations to preserve good fruit quality and extend storage life of fruit. For example, the Honeycrisp variety is unique, in that higher starch levels than other varieties are considered acceptable in storage. Honeycrisp tend to require a preconditioning period before being put into regular cold or CA storage, generally being held at 50° F for 5-7 days before storage.
Practices before and after harvest affect disease and decay in postharvest apples, and how well they will store. Things that can be done in the orchard: apply a late season fungicide to decrease pathogen levels that come to the packinghouse from the orchard. Fungicides need to be rotated to prevent resistance though. Orchard sanitation is important, pruning out dead branches and cankers where fungi live; good nutrition will improve fruit quality; harvesting at the correct maturity level; and cleaning bins to remove pathogens from soil and debris. In the packinghouse: Sanitation is imperative. Sanitizing rooms, packing lines, surfaces and equipment will kill fungal spores that cause decay in fruit.
Useful References and Resources:
More information specific to handling and storage of apples can be found using the links below. Additional resources can be located using the search box at the top of this page.
- Storage practices articles, WSU-TFREC Postharvest Information Network page.
- Apple article database, WSU-TFREC Postharvest Information Network page.
- Approved Chemicals for Use in Organic Postharvest Systems – eXtension article list, webpage. (Accessed: 1/19/17).
- Fruit metabolic responses to controlled atmosphere O2 and CO2 stress, J. Mattheis, et al., WTFRC Report, 2013.
- Testing biomarker-based tools for scald risk assessment during storage, D. Rudell, et al., WTFRC Report, 2014.
- Crucial tips to store Honeycrisp, R. Lehnert, Good Fruit Grower, October, 2015.
- European decision on DPA residues may end U.S. apple exports to Europe, R. Lehnert, Good Fruit Grower, January, 2013.