Physical and chemical control strategies to reduce postharvest decay of apples and other fresh fruit while maintaining quality: reducing dependence on pesticides
R. Saftner , W. Conway, J.Abbott , B. Leverentz and W. Janisiewicz
Proceedings of 26th International Horticultural Congress. Volume of Abstract . Toronto, Canada, 11-17 August, 2002. Abstract S09-O-215. pp. 273-274.
2002
บทคัดย่อ
Growing xonsumer concern about pesticide residues on the surface of fresh produce along with the development of pathogen resis tance to approved pesticides are prompting the development of alternative methods of maintaining produce quality during storage. One of these methods, Ca infiltration of apples, decreases the incidence of bitter pit, scald, water core, and internal breakdown, maintains fruit firmness and quality, and occurring and woundinoculated pathogen-induced decays. While rather effective at controlling decay, this treatment has received little commercial attention for a number of reasons among which is the relative inability to rapidly access and precisely adjust Ca absorbed from one lot of fruit to another. Another alternative muthod that has received considerable research attention is prestorage heat treatments. Exposing apples to 38 to 42 8 0C for 2 to 6 days suppresses softening and reduces decay incidence and development caused by postharvest pathogens. Heat treatment, however , offers little to no residual protection, and enhances some ripening characteristics, e.g., peel degreening and lowering acidity. A new rapid hot water brushing (HWB) method has been developed to simultaneously rinse and disinfect fresh fruit. The HWB method decreases the incidence of pathogen-induced decay, seals potential pathogen invasion sites, and/or slows some ripening characteristics in citrus, sweet peppers, lichee, corn, melon, mangos, and other fresh fruit. Still, the method does not offer adequate residual protection on its own so HWB is now being tested in combination with reduced levels of pesticides or other alternative methods. A new, low toxicity, gaseous inhibitor of ethylene action, 1-methylcyclopropene (1-MCP), has recently been developed to suppress ethylene-mediated ripening of many climacteric fruit especially apples. We found that 1-MCP treatment of preclimacteric Golden Delicious’ apples has little to on the incidence of decay but decreases decay development caused by wound-inoculated Penicillium expansum Lind, Botrytis cinerea Pers.:Fr., and Colletotrichum acutatum Simmonds (teleomorph Glomerella acutata J.C. Guerber & J.C. Correll sp. nov.) to about the same degree as controlled stmosphere (CA) storage, while more effectively inhibiting ripening than CA. Some 1-MCP dosages can prevent apple ripening, and occasionally 1-MCP treatments have been associated with surface and internal injury of apples, especially after prolonged CA storage. Other gaseous and natural chemical inhibitors of decay incidence and development in apples have been reported. It is unlikely that any of these alternative methods alone will be as efective as effective as pesticides. However, the development of a stratege combining several of these methods could result in the desired level of control. An example of the beneficial effects of various combinations of chemical, physical, and biological methods in apples will be presented.