Pulsed light technology for microbial inactivation

Pulsed ultraviolet-rich (PUV) light is a novel nonthermal high-peak power technology, which can achieve rapid inactivation of pathogenic and spoilage microorganisms. The aim of this study was to determine the effect of PUV-light for the inactivation of the bacterial species Staphylococcus epidermidis and the yeast species Saccharomyces cerevisiae whilst in liquid suspension. Results demonstrate that PUV-light exposure is highly microbicidal, with a 7-log₁₀ reduction of S. epidermidis being achieved after application of less than 10 pulses. S. cerevisiae was also inactivated, with 5-log₁₀ and 7-log₁₀ reductions being achieved after exposure to 10 and 75 pulses, respectively. This study also demonstrates that agitation of the sample during PUV exposure significantly enhances the inactivation rate of densely populated microbial suspensions.