Processing System and Thermal Process Design

Aseptic processing and packaging systems, facilities, and plant installations are complex, multicomponent systems used to produce sterile, shelf-stable food and beverage products. These products must not only have a long shelf life without refrigeration but must also have high quality measured as sensory quality and nutrient retention. Numerous design and operation requirements and characteristics need to be implemented in order to achieve the required criteria for aseptic operating conditions, product safety, and final product quality. Equipment, facility, and control systems must be functional, hygienically designed, able to clean, and sterilize, and plans and procedures must be developed to measure, monitor, record, document, and correct deviations. All of these requirements, criteria, and capabilities need to be integrated into the design, construction, validation, control, and operations of such systems. This chapter presents a detailed and extensive review of the scientific, engineering, and commercial production practices related to the design of aseptic processing systems. This covers topics ranging from the kinetic basis of thermal inactivation of bacteria and bacterial spores, and its application to continuous flow processes, the use of HACCP in aseptic processing, and a review of the design of heat exchangers and other functional elements of the aseptic processing systems such as pumps, valves, and aseptic tanks and an overview of procedures for their cleaning, sterilization, and maintenance of aseptic integrity. In the establishment of a process that reaches and maintains commercial sterility, the role of a qualified Process Authority is identified as crucial to achieve and sustain such high standards. Special emphasis is placed on the disciplined implementation of controls and preventive maintenance and the related training and motivating the personnel, from those involved in engineering, controls, and human interface programming to the quality assurance personnel and operators who are ultimately in charge of implementing these procedures on production plant floors. Potential sources and locations of loss of aseptic conditions, safety hazards, product quality degradation, and system and process contamination are identified, discussed, and design principles, control, and maintenance practices designed to prevent such occurrences based on regulatory agency requirements, established standards, and industrial practices are noted and recommended.