Pulsed Light and Pulsed Electric Field for Foods and Eggs

Abstract

Two new technologies for use in the food industry are described. The first method discussed uses intense pulses of light. This pulsed light (PureBright®) process uses short duration flashes of broad spectrum “white” light to kill all exposed microorganisms, including vegetative bacteria, microbial and fungal spores, viruses, and protozoan oocysts. Each pulse, or flash, of light lasts only a few hundred millionths of a second (i.e., a few hundred microseconds). The intensity of each flash of light is about 20,000 times the intensity of sunlight at the earth's surface. The flashes are typically applied at a rate of about one to tens of flashes per second. For most applications, a few flashes applied in a fraction of a second provide an effective treatment. High microbial kill can be achieved, for example, on the surfaces of packaging materials, on packaging and processing equipment, foods, and medical devices as well as on many other surfaces. In addition, some bulk materials such as water and air that allow penetration of the light can be sterilized. The results of tests to measure the effects of pulsed light on Salmonella enteritiditis on eggs are presented.The second method discussed uses multiple, short duration, high intensity electric field pulses to kill vegetative microorganisms in pumpable products. This pulsed electric field (or CoolPure™) process can be applied at modest temperatures at which no appreciable thermal damage occurs and the original taste, color, texture, and functionality of products can be retained.