Residence time distribution

Residence time distribution, usually abbreviated RTD, is how long the various components of a food product spend passing through a process vessel. Because flow is never perfectly uniform, some portions move faster and some slower, so they receive different amounts of heat or treatment. RTD is a critical factor in sizing holding tubes for aseptic processing of particulate foods and in designing continuous sterilization equipment for liquid foods: food safety requires that even the fastest-moving portion, which gets the least treatment, still receives an adequate process to destroy target microorganisms.