Abstract
Cadmium (Cd) levels in chocolate are a significant concern due to the toxic nature of this trace metal. This study presents a bioremediation treatment using Bacillus xiamenensis Luk70´s biomass in the post-harvesting process. The effect of the percentage of fermented beans, treatment time, nib pH, and concentration of bacteria applied to the reduction of Cd concentration was also studied, in addition to a cost analysis of pilot-scale bacteria production. Luk70 biomass with a 1:1 vegetative cell spore ratio applied to fermented cocoa beans at 90% can reduce nib Cd concentrations by a factor of 1.45 or 1.77, which to the best of our knowledge are the highest reductions in nib Cd concentration reductions reported to date without affecting the chocolate quality. The cost of producing Luk70 is estimated to be USD 0.56 per kg of wet cocoa beans, representing 14.4% of the current average price of Colombia´s wet cocoa beans. Although there are potential biosolutions for removing cadmium from cocoa, the economic costs and impact on the cocoa chain and producers must be considered.