|Hansen, James D|
Submitted to: Postharvest Biology and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/25/2005
Publication Date: 6/1/2006
Citation: Spotts, R.A., Serdani, M., Mielke, E.A., Bai, J., Chen, P.M., Hansen, J.D., Neven, L.G., Sanderson, P.G. 2006. Effect of a high-pressure hot water washing system on fruit quality, insects, and disease in apples and pears. Part II. Effect on postharvest decay of d'Anjou pear fruit. Postharvest Biology and Technology. 40:216-220. Interpretive Summary: The presence of decay causing microorganisms on commercially processed pears causes considerable losses of fruit and revenue to packing houses and growers. High pressure washers appeared to cause decay to spread throughout a load of fruit when being packed. Researchers at the Mid-Columbia Agricultural Research and Extension Center of Oregon State University and the USDA-ARS Yakima Agricultural Research Laboratory in Wapato, WA investigated the use of a modified high pressure washing system to reduce the spread of decay. The system added a heated contact loop which kept the water at 60°C for one minute to kill decay pathogens. When the spray water temperatures were kept at 30°C or below, fruit quality was acceptable. Also, the heated contact loop controlled the decay pathogens and prevented the additional spread of decay in pears run in the system. The HWP system described in this study will help pear packers in an integrated decay control strategy and improve pack out and profits.
Technical Abstract: A hot water pressure system (HWP) was evaluated for effect on conidia of P. expansum and on development of blue mold, gray mold, and mucor rot of d'Anjou pear fruit. Spores were removed from the system through dilution and also as a result of hot water in the system that was lethal to the spores. When the system was heated, viable spores were not detected after 2-4 hours of operation. Reductions in decay in the HWP system were 36, 29, and 13% for B. cinerea, M. piriformis, and P. expansum, respectively. The response of P. expansum appeared related to the length of time fruit was in cold storage. Heat injury was observed on fruit treated with 40º and 50 º C water but not on fruit at 30º C nozzle temperature. The HWP system described in this study should be considered as a component of an integrated decay control strategy.