A method for deactivating organisms used in fermenting a biomass to produce one or more bioproducts (e.g., ethanol, etc.) generally includes an operation of conveying the organisms from a fermentation chamber to a distillation unit, and then an operation of effecting a positive six-log kill of the organisms in the distillation unit. A system for producing the one or more bioproducts, making use of the method, generally includes the fermentation chamber for holding the organisms during the fermentation operation, and the distillation unit configured to receive the fermented biomass, including the organisms, from the fermentation chamber. The distillation unit is operable to effect the positive six-log kill of the organisms in the distillation unit. In some applications of the method and system, the organisms are genetically modified organisms.