Alternative Non-Thermal Approaches: Microwave, Ultrasound, Pulsed Electric Fields, Irradiation

This chapter proposes a description of some non-thermal technologies (microwave, ultrasound, pulsed technologies, irradiation) as suitable tools to inactivate foodborne pathogens and spoiling microorganisms in heat-sensitive foods.

Ultrasound (US) is defined as pressure waves with a frequencies of 20 kHz or more; pulsed electric field (PEF) processing involves treating foods placed between electrodes by high voltage pulses in the order of 20- 80 kV/cm (usually for a couple of microseconds); ionizing irradiation occurs when one or more electrons are removed from the electronic orbital of the atom; and microwaves (MW) are defined as electromagnetic waves in the range of infrared (IR) and radio waves (RF) with a wavelength ranging from 1 mm to 1 m and operating at a frequency ranging from 300 Mhz to 300 Ghz. Each technique allows killing of vegetative microorganisms but fail until now, when applied alone, to destroy spores.

This chapter reports some practical applications of the proposed approaches in food industry and also focuses on their drawbacks and limitations.

Keywords: Microwave, Ultrasound, Pulsed electric fields, Irradiation, Food applications of non-thermal approaches.