Fungal Infection of stored Arabic Cofee (Coffea arabica) beans in South Sulawesi Province,Indonesia

Abstract

Indonesia has retained its status as the world's fourth largest coffee producer after Brazil, Vietnam and Columbia, in which one of its well-known coffee is originated from Toraja region, South Sulawesi. Because of this, Indonesia has to compete with these countries in producing good quality coffee beans. The objectives of this research were (a) to obtain information on the postharvest handling methods of Arabica coffee (C. arabica) beans in Tana Toraja and North Toraja Regencies, and Makassar Municipality, and (b) to investigate the occurrence of fungi (including ochratoxin A producing fungi) in stored Arabica coffee beans collected from various stages of the delivery chain. Methods used in this study included surveys, interviews and sample collections in each level of delivery chain, which were conducted in May and July 2016. The moisture content and physical quality of the beans were also measured to determine the quality of the beans. The total number of coffee bean samples was 64, consisting of 27 samples from farmers, 15 samples from collectors, 13 samples from traders, and 9 samples from exporters. The results showed that the moisture content of coffee beans collected from farmers and collectors was higher than the maximum tolerable limit determined by SNI (13%), while the moisture content of beans collected from traders and exporters were lower. Based on the total defective value, coffee beans collected from farmers had more diverse grades than those at other levels. Penicillium citrinum was the dominat fungus found in coffee beans collected from farmers, collectors and traders, while Aspergillus niger was the dominant fungus found in coffee beans collected from exporters. At trader level, 46% of the samples was infected by Aspergillus ochraceus and A. niger, which are known as OTA-producing fungi. At exporter level, 44% of the samples was infected by A. ochraceus, while 78% of the samples was infected by A. niger. The postharvest handling methods of Arabica coffee beans conducted especially by farmers and collectors should be improved to minimize moisture content and to increase quality grade of coffee beans.