Inactivation mechanism of catalytic infrared against Pseudomonas aeruginosa and its decontamination application on dry green Sichuan pepper (Zanthoxylum schinifolium)

Abstract

Catalytic infrared (CIR) technology for sterilization has not been widely applied owing to the lack of comprehensive and in-depth mechanistic research. This study aims to explore further the inactivation mechanism of CIR against Pseudomonas aeruginosa in green Sichuan pepper (GSP). First, the working pattern of the CIR was investigated using a colony counting method in different layouts. The results indicated that the bacteriostatic effect on GSP was weaker than that on plates with low-dose CIR radiation, and both the surrounding air and surface moisture content affected the sterilization rate of P. aeruginosa. Second, the bacteriostatic mechanism of CIR against P. aeruginosa was investigated. The results indicated that the bacteriostatic effect of CIR could be mainly caused by the destruction of the cell membrane, inhibition of swimming motility, and membrane dysfunction simultaneously, and it was also caused by weaker DNA breakage compared with pulse strong light. Finally, the flavour influence of CIR in GSP was determined in terms of volatile oil content, aroma component, alkaloid content, and colour change. After 0–4 min of CIR treatment, the changes in the flavour of GSP were all within the acceptable range. Consequently, CIR technology is a promising approach for effective decontamination of the GSP surface, which works mainly on cell cover and can weakly penetrate the cell membrane.