U.S – Pulsed Light (PL) technology might soon be the ‘in thing’ in the food industry as a technique of inactivating microbial contaminants, after a study by Penn State University researchers proved its efficacy.
The study which was supported by the U.S. Department of Agriculture’s National Institute of Food and Agriculture (NIFA) tested the efficacy of pulsed light against various microbes, including pathogens and fungi.
Microbes such as Escherichia coli, Salmonella Typhimurium, Listeria monocytogenes, Bacillus cereus (vegetative cells and endospores), Aspergillus niger spores, and Penicillium roqueforti spores, were treated using three different broad-spectrum xenon gas flashlamps for up to 15 pulses.
Additionally, E. coli samples were treated with different filters applied to the pulsed light. Images of cell damage suggest that microbial sensitivity to pulsed light treatment differs for species, and that the majority of cell damage caused by the technique can be attributed to the UV portion of the light spectrum.
For two decades, members of the research team have studied pulsed light technology for food safety applications, reports Food Safety Magazine.
The lab has tested the technique against fruits, seeds, grains, cheese, milk, apple juice, and poultry products. The team has also simulated commercial production conditions to test the technology on eggs.
PL technology is a non-thermal technology, where sterilization and decontamination of food are achieved by impinging high-intensity light pulses on surfaces of foods and high-transmission liquids for a short duration of time.
The spectrum of light is typically between 200 and 1100 nm and includes UV, visible and infrared components, according to Campden BRI. The product is typically exposed to 1-20 pulses having an energy density in the range of 0.01 – 50 J.cm–2 at the surface.
The Pen State University researchers however point out that PL is not to be confused with continuous light. Continuous, low-intensity UV treatment has been used for antimicrobial purposes in the food industry since the 1960s.
Pulsed Light differs from continuous light in that it delivers a higher intensity of light, which results in greater microbial reduction in a shorter period of time. The team’s technique is designed to be deployed on a food conveyor and treat passing foods.
The team expresses their hopes that pulsed light technology will be widely adopted by the food industry, as the method has strong food safety potential.
In addition to its food safety benefits, research has shown that many food products are enhanced by exposure to Pulsed Light, says New Food.
For example, exposing mushrooms to Pulsed Light results in Vitamin D values that exceed the recommended daily allowance as determined by the Food and Nutrition Board of the National Research Council. Moreover, many foods’ shelf lives are extended through Pulsed Light treatment.
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