Effect of photo-active compounds curcumin and chlorophyllin against Salmonella and Campylobacter

Authors: URRUTIA, ANDREA - Auburn University; ORELLANA, LETICIA - Auburn University; SIERRA, KATHERINE - Auburn University; REINA, MARCO - Auburn University; FIGUEROA, JUAN - Auburn University; JACKSON, ALLY - Auburn University; MACKLIN, KENNETH - Auburn University; Buhr, Richard - Jeff; BOURASSA, DIANNA - Auburn University

Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/3/2023
Publication Date: N/A
Citation: N/A

Interpretive Summary: Salmonella and Campylobacter are two of the most common foodborne bacterial pathogens associated with raw poultry meat. Regulatory requirements and consumer concerns have increased the search for natural antimicrobials and emerging novel application technologies for poultry meat. The objective of this study was to determine the antimicrobial activity of two natural light-activated compounds curcumin (CUR) and chlorophyllin (CH) followed by LED light exposure for the reduction of Salmonella and Campylobacter. Peroxyacetic acid (PAA) is a common poultry processing aid and was used as a control. In 96 well plates, CUR and CH at concentrations of 100, 500, and 1,000 ppm, PAA at 100, 200, and 300 ppm, or distilled water (DW, serving as a positive control) were evaluated. Each well was inoculated with 10,000 cells of Salmonella or Campylobacter. The plates were then exposed to LED light at 430 nm wavelength for either 0 or 5 minutes. Data were statistically analyzed for CUR, CH, and PAA by concentration and light exposure at a significance P value of =0.05. No significant reductions were observed for Salmonella or Campylobacter when treated with CUR or CH at 100 to 1,000 ppm, or PAA at 100 ppm. However, when Salmonella was exposed to 200 ppm PAA, counts were reduced to 320 cells/mL, and when treated with 300 ppm PAA, there was no Salmonella recovery from the plates. Campylobacter was reduced to 510-850 cells/mL when treated with 200 ppm PAA. However, no further significant reduction was observed when Campylobacter was treated with 300 ppm PAA (200-500 cells/mL). These results indicate that CUR and CH were not effective as light-activated antimicrobials under the evaluated conditions for either Salmonella or Campylobacter, particularly in comparison to the commonly used antimicrobial, PAA.

Technical Abstract: Salmonella and Campylobacter are two of the most common pathogens associated with poultry meat. Regulatory restrictions and consumer concerns have increased the need for natural antimicrobials and emerging novel technologies. The objective of this study was to determine the antimicrobial activity of two natural photo-active compounds curcumin (CUR) and chlorophyllin (CH) followed by LED light exposure for the reduction of Salmonella and Campylobacter. Peroxyacetic acid (PAA), was also evaluated as a control. In 96 well plates, CUR and CH at concentrations of 100, 500, and 1,000 ppm, PAA at 100, 200, and 300 ppm, and distilled water (DW) were evaluated. Each well was inoculated with 10^4 CFU of Salmonella Typhimurium or Campylobacter. Plates were exposed to LED light (430 nm) for 0 or 5 mins. Data were analyzed for each antimicrobial by concentration and light exposure time using the GLM procedure with means separated by Tukeys HSD with significance at a P value of =0.05. For Salmonella, there was a significant main effect of treatment (P<0.0001), but time (P=0.368) and treatment*time interaction (P=0.999) were not significant. No reductions were observed for Salmonella or Campylobacter when treated with CUR, CH, or 100 ppm PAA. However, when Salmonella was treated with 200 ppm PAA, counts were reduced to 2.51-2.53 log10 CFU/mL. When Salmonella was treated with 300 ppm PAA, counts were below detectable levels. For Campylobacter, there was a significant main effect of treatment (P<0.0001) and a treatment*time interaction (P=0.035), but time (P=0.332) was not significant. Campylobacter was reduced when treated with 200 ppm PAA. However, no further reductions were observed when Campylobacter was treated with 300 ppm PAA (2.28-2.71 log10 CFU/mL). These results indicate that CUR and CH were not effective as antimicrobials under the evaluated conditions, particularly in comparison to the commonly used antimicrobial, PAA.