Association of coffee bean defects with ochratoxin A contamination in the samples originated from Ethiopia

Abstract

Filamentous fungi like Aspergillus, Penicillium, and Fusarium are the common microbial contaminants in many agricultural products including coffee beans. These fungal species can produce mycotoxins in coffee beans and exposes consumers to mycotoxin associated health risks. The purpose of this study was to examine the various types of coffee bean defects existed in coffee beans in relation to OTA contamination and search possible physical indicator to identify beans with OTA contamination. Coffee bean samples were evaluated visually for the presence of defective beans and the defects were counted and given scores. The samples were also assessed for fungal incidence and OTA contamination levels. The data was analyzed using R statistical software version 3.0.3 (2014-03-06). Significant positive correlation (r = 0.56, p < 0.00) existed between coffee bean defect points and OTA contamination levels. No statistical significant difference existed in median bean defect point within coffee bean processing methods, storage types, and storage material. The predominant coffee bean defects encountered in this study in descending order were black beans (41.6 %), immature bean (27.0 %), insect infested (20.5 %),  moldy beans (20.4.4 %), and broken beans (15.5%).  Ochratoxin A contamination levels in coffee beans were positively correlated with black beans (r = 0.33, p < 0.03), visible mold overgrowth (r = 0.80, p < 0.00), beans damaged by insects (r = 0.71, p < 0.00), and presence of husk (r = 0.67, p < 0.00).  Visual inspection of the incidence of these bean defects is a potential indication of OTA contamination in the beans. Therefore, local coffee consumers should avoid coffee beans with sign of mold overgrowth, black beans, beans with husk and damaged by insects as these types of coffee beans are most likely contaminated with OTA and causes health risk.