RESUMEN
Campylobacter jejuni is a major foodborne pathogen that causes gastroenteritis in humans. Chickens act as the reservoir host for C. jejuni, wherein the pathogen asymptomatically colonizes the ceca leading to contamination of carcasses during slaughter. The major colonization factors in C. jejuni include motility, intestinal epithelial attachment, acid/bile tolerance, and quorum sensing. Reducing the expression of the aforementioned factors could potentially reduce C. jejuni colonization in chickens. This study investigated the efficacy of subinhibitory concentration (SIC; compound concentration not inhibiting bacterial growth) of carvacrol in reducing the expression of C. jejuni colonization factors in vitro. Moreover, the effect of carvacrol on the expression of C. jejuni proteome was investigated using liquid chromatography-tandem mass spectrometry. The motility assay was conducted at 42°C, and the motility zone was measured after 24 h of incubation. For the adhesion assay, monolayers of primary chicken enterocytes (â¼105 cells/well) were inoculated with C. jejuni (6 log cfu/well) either in the presence or absence of carvacrol, and the adhered C. jejuni were enumerated after 90 min of incubation at 42°C. The effect of carvacrol on C. jejuni quorum sensing and susceptibility to acid/bile stress was investigated using a bioluminescence assay and an acid-bile survival assay, respectively. The SIC (0.002%) of carvacrol reduced the motility of C. jejuni strains S-8 and NCTC 81-176 by â¼50 and 35%, respectively (P < 0.05). Carvacrol inhibited C. jejuni S-8 and NCTC 81-176 adhesion to chicken enterocytes by â¼0.8 and 1.5 log cfu/mL, respectively (P < 0.05). Moreover, carvacrol reduced autoinducer-2 activity and increased the susceptibility of C. jejuni to acid and bile in both the strains (P < 0.05). Liquid chromatography-tandem mass spectrometry revealed that the SIC of carvacrol reduced the expression of selected C. jejuni colonization proteins critical for motility (methyl-accepting chemotaxis protein), adhesion (GroL), growth and metabolism (AspA, AcnB, Icd, Fba, Ppa, AnsA, Ldh, Eno, PurB-1), and anaerobic respiration (NapB, HydB, SdhA, NrfA) (P < 0.05). Results suggest the mechanisms by which carvacrol could reduce C. jejuni colonization in chickens.
Asunto(s)
Infecciones por Campylobacter , Campylobacter jejuni , Pollos , Cimenos , Microbioma Gastrointestinal , Proteoma , Animales , Infecciones por Campylobacter/veterinaria , Campylobacter jejuni/efectos de los fármacos , Pollos/microbiología , Cimenos/farmacología , Microbioma Gastrointestinal/efectos de los fármacos , Proteoma/efectos de los fármacosRESUMEN
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 (â¼8 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 â¼2.4 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.
Asunto(s)
Antibacterianos/farmacología , Bacterias Aerobias/efectos de los fármacos , Campylobacter jejuni/efectos de los fármacos , Manipulación de Alimentos/métodos , Monoterpenos/farmacología , Piel/microbiología , Animales , Pollos , Cimenos , Microbiología de AlimentosRESUMEN
Campylobacter jejuni infection in humans is strongly associated with the consumption of contaminated poultry products. With increasing consumer demand for minimally processed and natural product, there is a need for novel intervention strategies for controlling C. jejuni. Antimicrobial coatings are increasingly being used for preventing food contamination due to their efficacy and continuous protection of product. This study investigated the efficacy of pectin and chitosan coating fortified with eugenol to reduce C. jejuni on chicken wingettes. Pectin, chitosan, and eugenol are generally recognized as safe status compounds derived from berries, crustaceans, and cloves respectively. Each wingette was inoculated with a mixture of 4 wild-type strains of C. jejuni (approximately 107 CFU/sample) and randomly assigned to controls, pectin (3%), chitosan (2%), eugenol (0.5, 1, or 2%), or their combinations. Following 1 min of coating, wingettes were air-dried, vacuum sealed, and sampled on 0, 1, 3, 5, and 7 d of refrigerated storage for C. jejuni and aerobic counts (n = 5 wingettes/treatment/d). In addition, the effect of treatments on wingette color and expression of C. jejuni survival/virulence genes was evaluated. All 3 doses of eugenol or chitosan significantly reduced C. jejuni and aerobic bacteria from 0 d through 7 d. Incorporation of 2% eugenol in chitosan improved coating efficiency and reduced C. jejuni counts by approximately 3 Log CFU/sample at the end of 7 d of storage (P < 0.05). Similarly, the antimicrobial efficacy of pectin was improved by 2% eugenol and the coating reduced C. jejuni by approximately 2 Log CFU/sample at 7 d of storage. Chitosan coating with 2% eugenol also showed greater reductions of total aerobic counts as compared to individual treatments of eugenol and chitosan. No significant difference in the color of chicken wingettes was observed between treatments. Exposure of C. jejuni to eugenol, chitosan, or combination significantly modulated select genes encoding for motility, quorum sensing, and stress response. Results demonstrate the potential of pectin or chitosan coating fortified with eugenol as a postharvest intervention against C. jejuni contamination on poultry products.
Asunto(s)
Antibacterianos/farmacología , Campylobacter jejuni/efectos de los fármacos , Aditivos Alimentarios/farmacología , Productos Avícolas/microbiología , Animales , Bacterias Aerobias/efectos de los fármacos , Campylobacter jejuni/genética , Pollos , Quitosano/farmacología , Eugenol/farmacología , Contaminación de Alimentos/prevención & control , Manipulación de Alimentos/métodos , Pectinas/farmacología , Virulencia/genéticaRESUMEN
Human Campylobacter infections, a leading foodborne illness globally, has been linked with the high prevalence of this bacterium on raw retail chicken products. Reduction of Campylobacter counts on poultry products would greatly reduce the risk of subsequent infections in humans. To this end, this study investigated the potential of the phytophenolic compound ß-resorcylic acid (BR) to reduce Campylobacter counts on postharvest poultry (chicken skin or meat). Four trials in total, two each on thigh skin or breast meat, were conducted in which chicken skin or meat samples (2 ± 0.1 g; 10 samples per treatment) were inoculated with 50 µL (â¼106 CFU per sample) of a cocktail of four wild strains of C. jejuni. After 30 min of attachment, inoculated samples were dipped in a 0, 0.5, 1, or 2% BR solution for 30 s immediately followed by vigorously vortexing the samples in Butterfield's phosphate diluent and plating the supernatant for Campylobacter enumeration. In addition, the effect of BR on the color of skin and meat samples was studied. Moreover, the change in the expression of survival and virulence genes of C. jejuni exposed to BR was evaluated. Data were analyzed by the PROC MIXED procedure of SAS (P < 0.05; SAS Institute Inc., Cary, NC). All BR treatments significantly reduced Campylobacter populations on both chicken or meat samples by 1 to 3 log CFU/g compared with non-BR-treated washed controls. No significant difference in the lightness, redness, and yellowness of skin and meat samples was observed on exposure to BR wash (P > 0.05). Real-time PCR results revealed that BR treatment down-regulated expression of select genes coding for motility (motA, motB) and attachment (cadF, ciaB) in the majority of C. jejuni strains. Stress response genes (sodB, katA) were upregulated in C. jejuni S-8 (P < 0.05). Overall, our results suggest that BR could be effectively used as antimicrobial dip treatment during poultry processing for reducing Campylobacter on chicken carcasses.