Carvacrol antimicrobial wash treatments reduce Campylobacter jejuni and aerobic bacteria on broiler chicken skin

Authors: SHRESTHA, SANDIP - University Of Arkansas; WAGLE, BASANTA - University Of Arkansas; UPADHYAY, ABHINAV - University Of Arkansas; ARSI, KOMALA - University Of Arkansas; DONOGHUE, DAN - University Of Arkansas; Donoghue, Ann - Annie

Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/21/2019
Publication Date: 9/1/2019
Citation: Shrestha, S., Wagle, B.R., Upadhyay, A., Arsi, K., Donoghue, D.J., Donoghue, A.M. 2019. Carvacrol antimicrobial wash treatments reduce Campylobacter jejuni and aerobic bacteria on broiler chicken skin. Poultry Science. 98:(9)4073-4083. https://doi.org/10.3382/ps/pez198.
DOI: https://doi.org/10.3382/ps/pez198

Interpretive Summary: Campylobacter jejuni, a major cause of human gastroenteritis worldwide, is often associated with the consumption of contaminated poultry products. A reduction in Campylobacter jejuni counts in postharvest poultry could drastically reduce the incidence of human illness caused by this pathogen. Most of the meat spoilage bacteria are aerobic in nature. Thus, reducing total aerobic counts in meat products could increase the shelf-life of the products. This study investigated the efficacy of the generally recognized as safe compound, carvacrol (CR) as a wash treatment in reducing C. jejuni and aerobic bacteria on chicken skin. Two separate studies, each with two trials were conducted. In the first study, the efficacy of CR suspension (0, 0.25, 0.5, 1 and 2%) was investigated, whereas in the second, the efficacy of CR as emulsion and nanoemulsion was studied. In both studies, skin samples were inoculated with 50 µL of a cocktail of four wild strains of C. jejuni. After 30 min of attachment, inoculated skin samples were washed with the respective treatments for 1 min, subjected to drip dry for 2 min and processed at 0, 8, 24 h post treatment for enumeration of C. jejuni and aerobic bacterial counts (n=5/treatment/time point). In addition, the effect of treatments on the color of chicken skin was evaluated. All the tested doses of CR suspension consistently reduced C. jejuni counts across all time points. The 2% CR wash was the most effective treatment and reduced 99.99% C. jejuni. In addition, 1% and 2% CR significantly reduced aerobic counts at all time points. The results from the second study suggest that anti-Campylobacter efficacy of CR emulsion or nanoemulsion treatments were not improved compared to CR suspension. Several CR suspension treatments were more effective than corresponding emulsion and nanoemulsion treatments. No significant difference in color of skin samples between treatments was observed (P > 0.05). The results suggest that CR could potentially be used as an antimicrobial wash treatment in postharvest poultry.

Technical Abstract: Campylobacter jejuni, a major cause of human gastroenteritis worldwide, is often associated with the consumption of contaminated poultry products. With increasing consumer preference to natural and minimally processed foods, interventions utilizing natural antimicrobials for controlling C. jejuni on poultry products is gaining popularity. This study investigated the efficacy of the generally recognized as safe compound, carvacrol (CR) as a wash treatment in reducing C. jejuni and aerobic bacteria on chicken skin. Two separate studies, each with two trials were conducted. In the first study, the efficacy of CR suspension (0, 0.25, 0.5, 1 and 2%) was investigated, whereas in the second, the efficacy of CR as emulsion and nanoemulsion was studied. In both studies, skin samples were inoculated with 50 µL (~8 log10 cfu/sample) of a cocktail of four wild strains of C. jejuni. After 30 min of attachment, inoculated skin samples were washed with the respective treatments for 1 min, subjected to drip dry for 2 min and processed at 0, 8, 24 h post treatment for enumeration of C. jejuni and aerobic bacterial counts (n=5/treatment/time point). In addition, the effect of treatments on the color of chicken skin was evaluated. The data were analyzed by ANOVA using PROC MIXED procedure of SAS 9.3. All the tested doses of CR suspension consistently reduced C. jejuni counts across all time points. The 2% CR wash was the most effective treatment and reduced C. jejuni counts by ~4 log10 cfu/sample (P < 0.05). In addition, 1% and 2% CR significantly reduced aerobic counts (up to 2 log10 cfu/sample) at all time points. The results from the second study suggest that anti-Campylobacter efficacy of CR emulsion or nanoemulsion treatments were not improved compared to CR suspension. Several CR suspension treatments were more effective than corresponding emulsion and nanoemulsion treatments. No significant difference in colors of skin samples between treatments was observed (P > 0.05). The results suggest that CR could potentially be used as an antimicrobial wash treatment in postharvest poultry.