Effects of the photosensitizer curcumin in inactivating foodborne pathogens on chicken skin

This study investigated the antimicrobial efficacy of the water-soluble photosensitizer curcumin (PSC) on liquid media and chicken skin. The water-soluble PSC showed strong absorption at 410 nm, and the light-emitting diode (LED) used to activate PSC had strong emission at 430 nm with power density of 107 W/m². Listeria monocytogenes (3 isolates) and Salmonella (8 isolates) were evaluated in this study. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of PSC for L. monocytogenes were 10 ppm and 20 ppm, respectively. For Salmonella, 200 ppm of PSC led to maximum 3.6 log reduction. No significant differences for antimicrobial activities among different incubation (1, 2.5, and 5 min) or light dose (6.4, 32.1, and 64.2 kJ/m²) were observed. Compared with the water control, no significant color change was observed on chicken skin exposed to illumination equal to or greater than 32.1 kJ/m². After 5-min incubation followed by 32.1 kJ/m² of illumination, treatment with 300 ppm of PSC resulted in 2.9 and 1.5 log CFU/cm² of L. monocytogenes and Salmonella on chicken skin, respectively. PSC showed equivalent or better efficacy in reducing the population of foodborne pathogens on chicken skin, as compared with a commercial antimicrobial containing 300 ppm of peracetic acid. This study suggests that PSC effectively inactivates pathogens on media and chicken skin without causing skin discoloration, indicating a potential application as an antimicrobial intervention in the poultry industry.