Modelling the effect of UV light at different wavelengths and treatment combinations on the inactivation of Campylobacter jejuni

Abstract

Application of novel decontamination strategies such as Ultraviolet (UV) irradiation are required to mitigate the risks associated with Campylobacter jejuni in food. This study evaluated the use of a light-emitting diode (LED) based technology to inactivate C. jejuni NCTC 11168 in Maximum Recovery Diluent (MRD) at wavelengths of 280, 300 and 365 nm and combinations. To assess the survival curves, two linear (Log linear (LL) and Linear and Shoulder) and two non-linear models (Weibull and Double Weibull) were fitted. UV exposures showed different antimicrobial effects where a combination of 280/300 nm was the most effective treatment with a 4Dt value of 5 s observed in a bacterial suspension of 5 log CFU/mL. Moreover, the LL model was the most robust model to describe the inactivation kinetics of Campylobacter when exposed to UV and therefore, modelling tools could be applied to predict the efficiency of UV light in a model solution.

Industrial relevance: Light-based technologies like UV light are identified in the literature as potential alternatives to assure the decontamination of surfaces, liquids and solid food. However, some of these techniques require further investigation. The present study evaluated the use of a LED system and effect of combined wavelengths in the inactivation of Campylobacter through predictive modelling. This technique was observed to predict and explain kinetics of inactivation of Campylobacter and could be key in the scaling-up process of UV light at industrial level.