High Pressure Sub-Zero Temperature Concepts for Improving Microbial Safety and Maintaining Food Quality: Background Fundamentals, Equipment Issues and Applications

Ensuring food safety and quality is paramount for consumers. Water, a fundamental component of food, exhibits diverse crystalline structures under high pressure (HP) and experiences alterations in freezing points. Exploiting these water characteristics has spurred the development of innovative high-pressure sub-zero temperature (HPST) techniques. This review systematically categorizes HPST technologies based on their adherence to the temperature-pressure phase diagram, encompassing high-pressure freezing (HPF), high-pressure thawing (HPT), solid-solid phase transition (SSPT) treatment, and isochoric freezing (IF). Furthermore, the review elaborates on the latest advancements in HP cryogenic equipment, focusing on temperature and pressure control units. The underlying principles of the HPST technologies and their inactivation effects on various food materials, such as beverages and meat, are elaborated, and the effects of the HPST treatments on the appearance, texture, moisture content, and other quality characteristics of the food products are discussed. Emphasis is placed on delineating the advantages, disadvantages, and application scopes of different HPST technologies. To propel comprehensive research and foster the industrialization of HPST technology, future endeavors should concentrate on validating the commercial viability of HP cryogenic equipment, establishing dependable temperature regulation and detection systems, and compiling a comprehensive melting point database for real food under HP conditions.