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

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 are 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 2 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 suspension, emulsion, and nanoemulsion was studied. In both studies, skin samples were inoculated with 50 μL (∼8 log₁₀ cfu/sample) of a cocktail of 4 wild strains of C. jejuni. After 30 min of attachment, samples were washed with the respective treatments for 1 min, drip dried 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. Data were analyzed using PROC MIXED procedure of SAS. In the first study, all the tested doses of CR suspension consistently reduced C. jejuni counts across all time points. The 2% CR suspension wash reduced C. jejuni counts by ∼2.4 to 4 log₁₀ cfu/sample (P < 0.05). In addition, 1% and 2% CR suspensions significantly reduced aerobic counts at all the time points. The results from the second study suggest that anti-Campylobacter efficacy of CR emulsion or nanoemulsion treatments was not improved compared to CR suspension. Several CR suspension treatments were more effective than corresponding emulsion or nanoemulsion treatments. No significant differences were observed in the color of the samples between treatments (P > 0.05). The results suggest that CR could potentially be used as an antimicrobial wash treatment in postharvest poultry.