The invention relates to a process for the production of a vaccine against bacterial pathogens which produce an AB toxin, like Clostridium, comprising (a) culturing the pathogen under conditions where the AB toxin is produced, and harvesting the culture (b) cleaving the AB toxin enzymatically in vitro, preferably using inositol hexaphosphate as a co-factor, and (c) combining the composition of step (b) with a pharmaceutically acceptable carrier.