Certified Food Safety Center
Types of Non-Thermal Process Validation
Pulsed Electrical Fields
Radiation for the treatment of food is achieved through the application of gamma rays (with Co-60 or Cesium-137 radioisotope), electron beams (high energy of up to 10 MeV), or X-rays (high energy of up to 5 MeV). Radiation principles explain how the gamma rays, e-beams and X-rays interact with matter. These interactions result in the formation of energetic electrons at random throughout the matter, which cause the formation of energetic molecular ions. These ions may be subject to electron capture and dissociation, as well as rapid rearrangement through ion-molecule reactions, or they may dissociate with time depending on the complexity of the molecular ion. Effects of radiation on matter depend on the type of the radiation and its energy level, as well as the composition, physical state, temperature and the atmospheric environment of the absorbing material. With proper application, irradiation can be an effective means of eliminating and/or reducing the microbial load and thus the foodborne diseases they induce, thereby improving the safety of many foods as well as extending their shelf life.
Supercritical Carbon Dioxide
Pulsed light is a surface irradiation system and not a penetration system. It is primarily useful for surface kill of microorganisms, or for liquids if you can run liquids through as a very thin film. Pulsed light consists of very intense and short flashes of light with wavelengths from UV to NIR, emitted by Xenon discharge lamps. Despite its approval for surface microorganism control in foods by FDA, PL is not yet commercially used, mostly due to the lack of knowledge regarding the critical factors of influence and the inactivation mechanisms.
High Hydrostatic Pressure Processing (HPP)
High hydrostatic pressure processing (also known as high pressure processing (HPP) and ultra-high-pressure processing (UHP) is a method of food processing in which foods are treated under high pressure (up to 6000 atm) to achieve microbial inactivation. Typically, the food product is packaged into flexible containers which are then placed into a high pressure chamber filled with a pressure-transmitting medium (usually water). The fluid filled chamber is then pressurized with the pressure being transmitted through the package and into the food itself. Because HPP causes minimal changes in the freshness characteristics of foods by eliminating thermal degradation, HPP results in foods with a fresher flavor profile and better appearance, texture, and nutrition compared to thermally processed products.
Radio Frequency and Microwave
The bactericidal effect of ultrasound is generally attributed to intracellular cavitation. It is proposed that micro-mechanical shocks are created by making and breaking microscopic bubbles induced by fluctuating pressures under the ultrasonic process. These shocks disrupt cellular structural and functional components up to the point of cell lysis. Most applications of ultrasound involve its use in combination with other preservation methods.