Apart from the formation of flavour compounds and colour, the main effect of conventional hot-air roasting is a significant reduction of the microbial load of fermented cocoa beans. The present study was undertaken to evaluate whether a thermal impact during the treatment of cocoa nibs in a refiner conche contributes to decontamination. A viable count reduction of approx. 4 log10 units was achieved when the temperature of the refiner drum was set to 100 °C, and water was added during thermal treatment for 6 h. It was also demonstrated that such a refining in the conche results in particle size distributions with an x90 diameter