This study is devoted to the development of a UV fluorimetry sensor capable of real-time monitoring of the decontamination process of microbiological pathogens by hydrogen peroxide vapour (HPV) treatment. The sensor is operating on the autofluorescence signal of tryptophan. The Bacillus atrophaeus (B. atrophaeus) and Geobacillus stearothermophilus (G. stearothermophilus) spores were exposed to HPV and the resulting dynamic change in tryptophan fluorescence intensity as a function of time was recorded and analysed. It was revealed that the introduced HPV atmosphere caused a 4-time decrease in the fluorescence intensity of the tryptophan emission due to the interaction of HPV with the spores. It was shown that achieving a persistent minimal level of the autofluorescence signal due to the microorganism-bound tryptophan during the defined time period is well correlated with the efficiency of the ongoing decontamination process in the HPV treatment course. Therefore, the progress of the HPV decontamination procedure can be firmly evaluated, using fluorescence data obtained in real time and the validity of the method was demonstrated by comparing the fluorescence data with the reference information obtained by implementing classical microbiology viability tests (incl. time behaviour) for various microorganisms in the HPV atmosphere.
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