Abstract: Methods and related apparatus for improving the efficacy of antimicrobial agents within processing tanks. Processing tanks can include side streams for introducing antimicrobial agents into the processing tanks. The antimicrobial agents will be added and mixed in the side stream to form a processing solution. Additional actions can be conducted on the processing solution within the side stream including any and or all of heating, pumping, sampling, measuring, testing and pH adjustment of the processing solution. The processing solution is divided into at least two processing solution steams, which can be introduced at two different and distinct locations within the processing tank such as a carcass introduction end and a carcass removal end. By simultaneously introducing at least two processing solution streams at different locations of the processing tank, large concentration gradients of the antimicrobial agent are avoided.