Enhanced inactivation of Cronobacter sakazakii on various surfaces through bubble water assisted 405 nm light and folic acid treatment

Abstract

The present study investigated inactivation of Cronobacter sakazakii inoculated on surface materials by bubble water–aided 405 nm light combined with folic acid (LFA). Polypropylene and silicon, widely used in baby feeding bottles, were used as surface materials, and inactivation of pathogens from surface materials and from water containing pathogens detached from surface materials was investigated. The combination of 405 nm light with folic acid accelerated the reduction of pathogens compared with all individual treatments. Even though the reduction of C. sakazakii inoculated on polypropylene was higher than that inoculated on silicon, significant differences were not observed for most experimental conditions. When folic acid was re-used for the maximum five times, the reduction of C. sakazakii inoculated on polypropylene and silicon did not differ significantly. Studies on the bactericidal mechanism of the combined treatment with reactive oxygen species scavengers revealed that hydrogen peroxide, singlet oxygen, and superoxide had significant effects on inactivation of C. sakazakii. When powdered infant formula (with and without lactic acid bacteria) was used as interference materials, reduction levels decreased compared to the control. The results of the present study showed that bubble water–aided combined treatment of 405 nm light and folic acidcan be used effectively to inactivate C. sakazakii on surface materials.