Untersuchungen und Prozessbegleitung zur Praxiseinführung von Heißwassertauchanlagen im ökologischen Kernobstanbau

Summary

In general, organic grown apples (Malus x domestica Borkh.) are not treated with chemical fungicides to prevent storage decay and these fruits may suffer up to 30% decay during storage. Preliminary experiments had shown that hot water dipping of apples may be an alternative. To inhibit Gloeosporium rot (Pezicula alba, P. malicortis) water temperature may be of about 50°C and dipping time from 60 sec up to 180 sec. The present investigation was conducted to test different ranges of temperatures and dipping time periods in different apple cultivars over a three year investigation. The objective was to determinate the suitable hot water treatment that prevents decay incidence and maintains fruit quality (firmness, scale symptoms). For the reduction of post harvest decay the treatment 53°C and 180 sec is recommended; that was found suitable for `Topaz`. For cultivars with a sensitivity to skin disorders dips for 120 sec or 180 sec are recommended; that was found best for ´Elstar´(51°C), ´Ingrid Marie` (49°C), ´Holsteiner Cox´(51°C) und ´Boskoop´(51°C). A big box dipping machine was invented in northern Germany to improve the situation on the farms. The parameters we found in the trails were used as standards on the developing side. Today’s ma-chine runs with a precision temperature range of one K inside the box.