Select Phytochemicals Reduce Campylobacter jejuni in Postharvest Poultry and Modulate the Virulence Attributes of C. jejuni

Abstract

Consumption or handling of poultry and poultry products contaminated with Campylobacter species are a leading cause of foodborne illness in humans. Current strategies employed to reduce Campylobacter in live chickens provide inconsistent results indicating the need for an alternative approach. This study investigated the efficacy of phytochemicals, namely, turmeric, curcumin, allyl sulfide, garlic oil, and ginger oil, to reduce Campylobacter jejuni in postharvest poultry and sought to delineate the underlying mechanisms of action. Two experiments were conducted on the thigh skin of the chicken, and each experiment was repeated twice. Samples were inoculated with 50 μl (∼107 CFU/sample) of C. jejuni strain S-8 and allowed to adhere for 30 min. Skin samples were dipped into their respective prechilled treatment solutions (0.25 and 0.5% in experiments 1 and 2, respectively) at 4°C for an hour to simulate chilling tank treatment, followed by plating to enumerate C. jejuni (n = 3 samples/treatment/trial). The mechanisms of action(s) were investigated using subinhibitory concentration (SIC) in adhesion, quorum sensing, and gene expression analyses. Adhesion assay was conducted on the monolayers of ATCC CRL-1590 chicken embryo cells challenged with C. jejuni and incubated in the presence or absence of phytochemicals for 1.5 h, followed by plating to enumerate adhered C. jejuni. The effects of phytochemicals on quorum sensing and cell viability were investigated using Vibrio harveyi bioluminescence and LIVE/Dead BacLightTM bacterial viability assays, respectively. In addition, droplet digital PCR determined the gene expression analyses of C. jejuni exposed to phytochemicals. Data were analyzed by GraphPad Prism version 9. C. jejuni counts were reduced by 1.0–1.5 Log CFU/sample with garlic oil or ginger oil at 0.25 and 0.5% (p < 0.05). The selected phytochemicals (except curcumin) reduced the adhesion of C. jejuni to chicken embryo cells (p < 0.05). In addition, all the phytochemicals at SIC reduced quorum sensing of C. jejuni (p < 0.05). The cell viability test revealed that cells treated with 0.25% of phytochemicals had compromised cell membranes indicating this as a mechanism that phytochemicals use to damage/kill C. jejuni. This study supports that the application of phytochemicals in postharvest poultry would significantly reduce C. jejuni in poultry meat.

Ability of Garlic and Ginger Oil to Reduce Salmonella in Post-Harvest Poultry

“…The antimicrobial activity of garlic and ginger oil against Salmonella on chicken skin was determined according to a previously published protocol [ 10 , 21 ]. A total of three independent experiments were conducted.…”

“…The sub-inhibitory concentration (SIC) of garlic and ginger oil was determined according to a previously published protocol [ 10 ]. Two-fold dilutions of garlic and ginger oil (0, 2.5, 1.25, 0.625, 0.312, 0.156, 0.078, 0.039%) were prepared in a sterile 96-well plate (Costar, Corning, NY, USA) containing 100 μL of TSB broth.…”

“…This has made antibiotic use in livestock a significant public health concern and created a need for safer antibiotic alternatives. During post-harvest, peracetic acid (PAA) is used to disinfect commercial poultry products [ 10 ]. However, consumer acceptance of PAA diminishes with an increased preference for natural alternatives.…”

“…Previously, we demonstrated the ability of garlic and ginger oil to damage/kill the foodborne pathogen Campylobacter jejuni , inhibit its adhesion to chicken embryo cells, and reduce its quorum sensing [ 10 ]. Therefore, the goal of this study was to further determine the suitability of these oils as antimicrobials for poultry production by investigating their antimicrobial activity individually and the combination of both against three Salmonella serovars ( S. enteritidis , S. typhimurium , and S. infantis ) and to determine their possible mode of action.…”

Rhodiola rosea Reduces Intercellular Signaling in Campylobacter jejuni

“…Various phytochemicals inhibit C. jejuni intercellular signaling. Examples of this include citrus ethanolic extracts [ 11 ], epigallocatechin gallate (EGCG) [ 12 ], resveratrol inclusion complexes [ 13 ], coriander essential oil, linalool [ 14 ], Euodia ruticarpa ethanolic extract [ 15 ], carvacrol [ 16 ], curcumin, allyl sulfide, garlic oil, and ginger oil [ 17 ]. Šimunović et al [ 9 ] investigated the correlation of QS inhibition with changes in C. jejuni motility, adhesion to polystyrene surfaces, and adhesion to and invasion of INT407 cells.…”