1. 1. Thermal Processing Principles 1. 1. 1. ThermalProcessing A generation ago the title of this book would have contained such terms as canning, bottling, sterilization and heat preservation; however, with the passage of time it has become necessary to use a more general title. The term thermal processing is used here in a general sense and relates to the determination of heating conditions required to produce microbiologically safe products of acce- able eating quality. It conveys the essential point that this book is concerned with the heating and cooling of packaged food products. The only attempt to produce a generic title has been due to Bitting (1937), who used the term appertizing, after the process developed and commercialized by Nicholas Appert (1810) to describe the canning and bottling process. Despite the need for a generic term, rather surprisingly, this has never been used to any great extent in the technical press. The phrase packaged foods is also used in a general sense, and we shall be concerned with a variety of packaging materials, not just tin-plate, aluminum and glass, but also rigid and semi-rigid plastic materials formed into the shape of cans, pouches and bottles. The products known originally as canned or bottled products are now referred to as heat-preserved foods or thermally processed foods. Thermal Processing is part of a much wider ?eld-that of industrial sterilization-whichincludesmedicalandpharmaceutical applications. Thosec- cerned with these subjects will ?nd much of the information in this book will apply directly to their technologies.

Thermal Processing of Packaged Foods, Second Edition, discusses the physical and engineering aspects of the thermal processing of packaged foods and examines the methods that have been used to establish the time and temperature of processes suitable to achieve adequate sterilization or pasteurization of the packaged food.
New features in this edition include:
The increased use of new packaging materials, including retortable pouches and the use of containers made from other plastic composite materials
The application of newer processing methods which use heat transfer media such as hot water, air/steam, and steam/water, which are necessary for the newer forms of packaging material
New methods of theoretically calculating the heat transfer characteristics during processing, including three-dimensional modeling and application of computerized fluid dynamics (CFD) techniques
The implications of newer models for microbial destruction
The development of process schedules for quality optimization in newer packaging materials
Important new aspects of methods of retort control
Unlike other texts on thermal processing, which cover very adequately the technology of the subject, the unique emphasis of this text is on processing engineering and its relation to the safety of processed foods products.
About the Authors
S. Daniel Holdsworth, a former researcher for 25 years with the Campden and Chorleywood Food Research Association.
Ricardo Simpson,a professor in Universidad Técnica Federico Santa María, Department of Chemical, Biotechnological and Environmental Processes.