The research related on formulation of yeast powder to control ochratoxin A (OTA) producing fungus in Arabica coffee beans was conducted since March until November 2020. This research aimed 1) to test some carrier and additives materials on the survival of yeast Issatchenkia orientalis BIO 211287, and 2) to test the effect of powder formulation in combination yeast, carrier and additives materials on OTA production and the taste of Arabica coffee processed using semi-wet method. Methodology of these research were 3 stages, i.e. screening of additive materials that could increase the activity of antagonistic yeast using well method, testing of additive and carrier materials combinations for yeast survival, and biocontrol of OTA producing fungus (Aspergillus ochraceus BIO 37310) using formulation powder of I. orientalis BIO 211287 in vivo. Result showed that the highest yeast survival was found in 0.5% chitosan shrimp shell powder additive (80.9%) and could inhibit 100% of A. ochraceus. It means that 0.5% chitosan shrimp shell powder was the best of additive materials to keep yeast survival and to increase the activity of antagonistic yeast on OTA producing fungus. Tapioca powder was the best of carrier materials to keep yeast survival for 3 months of storage. Issatchenkia orientalis BIO 211287 could inhibit OTA producing fungal growth in vitro, and also increased the taste of Arabica coffee beans processed by semi-wet method.

Key words : Arabica coffee beans, Issatchenkia orientalis, OTA producing fungus, yeast powder formulation