Abstract: A sequential delivery assembly (30) sequentially releases three different treatment materials into a fluid flow path (24) to form a treatment fluid with a composition which varies throughout a cleaning and microbial decontamination cycle. A chamber (12) receives items to be cleaned and decontaminated. A pump (22) pumps the treatment fluid from the sequential delivery assembly along a fluid flow line (24) to nozzles (16, 18) disposed within the chamber. The nozzles spray the treatment fluid over the items to be cleaned and decontaminated. The delivery assembly includes a well (34) for receiving a three compartment cup (44). The cup contains a first compartment (70) which includes a cleaning material (76), such as a detergent. A second compartment (72) contains pre-treatment materials (78), such as buffers and corrosion inhibitors, which prepare the system for receiving a microbial decontaminant (80), such as a concentrated solution of peracetic acid, contained in the third compartment (74).