Comparison of ozone and chlorine in low concentrations as sanitizing agents of chicken carcasses in the water immersion chiller

Microbial profile of broiler carcasses processed at a university scale mobile poultry processing unit

Chicken and chicken products have been associated with foodborne pathogens such as Salmonella, Campylobacter, and Escherichia coli (E. coli). Poultry comprises an important segment of the agricultural economy (75 million birds processed as of 2019) in West Virginia (WV). The risk of pathogens on processed chickens has risen with the increased popularity of mobile poultry processing units (MPPUs). This study evaluated the microbial safety of broilers processed in a MPPU in WV. This study assessed aerobic plate counts (APCs), E. coli counts and the presence/absence of Salmonella and Campylobacter on 96 broiler carcasses following each MPPU step of scalding, eviscerating, and chilling. Samples were either chilled in ice water only (W) or ice water with 5 ppm chlorine (CW). The highest number of bacteria recovered from carcasses were APCs (4.21 log10CFU/mL) and E. coli (3.77 log10CFU/mL; P = 0.02). A total reduction of 0.30 (P = 0.10) and 0.63 (P = 0.01) log10CFU/mL for APCs and E. coli, respectively, occurred from chilling carcasses in CW. Overall, results show that E. coli, Salmonella, and Campylobacter were significantly (P < 0.05) reduced from the initial scalding to the chilling step. However, Salmonella frequency doubled (15.63-34.38%) after the evisceration step, indicating that washing carcasses after evisceration may be a critical control point in preventing cross-contamination by Salmonella. Proper chilling is also an important microbial mitigation step in MPPU processing. Results indicate that Campylobacter was more resistant to chilling than Salmonella. Campylobacter was not completely inactivated until carcasses were chilled in CW, whereas W was sufficient to reduce Salmonella on carcasses. The results led to the conclusion that although 5 ppm chlorine (Cl2) achieved more bacterial reductions than water alone, the reductions were not always significant (P > 0.05). Further MPPU studies are needed to verify more effective chilling and processing strategies.

Effect of gaseous ozone application during chilling on microbial and quality attributes of pig carcasses

Ozone application has been suggested as an additional measure to the slaughter animals under hygiene programs. In this study, we determined the efficacy of gaseous ozone applied to pig carcasses during chilling (16 h at 2-5°C). Forty carcasses were allocated to each treatment: control, without ozone application (T1) and 5 ppm gaseous ozone application (T2), divided in two 4-h periods. The carcasses were sampled before and after chilling. The average counts of total aerobic mesophilic (TAM) bacteria before chilling were not different (p = 0.55) between T1 and T2. In turn, after chilling, the ozone-treated carcasses had significantly reduced about 0.4 colony-forming units (CFU)/cm² of TAM counts (p < 0.001) than the control carcasses. No significant reduction was observed in the number of carcasses positive for Listeria sp. and Escherichia coli after gaseous ozone treatment; while a tendency (p = 0.08) of lower number of Salmonella positive carcasses in T2 was observed. Common macrorestriction (pulsed-field gel electrophoresis) patterns of S. enterica were observed in the carcasses before and after chilling. Pork samples from treated and untreated carcasses with ozone showed no lipid oxidation or altered color and pH. The results indicate that the gaseous ozone in the tested protocol is effective in reducing TAM populations, but not effective in decreasing the number of carcasses positive for E. coli and Listeria sp. Regarding Salmonella, the tendency of positive carcasses reduction may encourage further studies by testing other protocols of gaseous ozone application inside the chilling chamber.

Antimicrobial Efficacy of Aqueous Ozone and Ozone-Lactic Acid Blend on Salmonella-Contaminated Chicken Drumsticks Using Multiple Sequential Soaking and Spraying Approaches

Ozone (O3) is an attractive alternative antimicrobial in the poultry processing industry. The optimal operational conditions of O3 for improving food safety concerns are poorly understood. The main objective of this study was therefore to characterize the microbial killing capacity of aqueous O3 and O3-lactic acid blend (O3-LA) at different operational conditions on chicken drumsticks contaminated with high Salmonella load using sequential soaking and spraying approaches. Four hundred forty-eight chicken drumsticks (280-310 g) were soaked into two-strain Salmonella cocktail, and the initial load on the surface of the skin was 6.9-log10 cell forming unit (CFU)/cm2 [95% confidence interval (CI), 6.8-7.0]. The contaminated drumsticks were then sequentially (10×) soaked and sprayed with aqueous O3 (8 ppm) and O3-LA. Following O3 exposure, quantitative bacterial cultures were performed on the post-soaking and post-spraying water, skin surface, and subcutaneous (SC) of each drumstick using 3MTM PetrifilmTM Rapid Aerobic Count Plate (RAC) and plate reader. The average killing capacity of aqueous O3/cycle on the skin surface was 1.6-log10/cm2 (95% CI, 1.5-1.8-log10/cm2) and 1.2-log10/cm2 (95% CI, 1.0-1.4-log10/cm2), and it was 1.1-log10/cm2 (95% CI, 0.9-1.3-log10/cm2) and 0.9-log10/cm2 (95% CI, 0.7-1.1-log10/cm2) in SC for soaking and spraying approaches, respectively. Six sequential soaking and seven sequential spraying cycles with ozonated water of 8 ppm reduced the heavy Salmonella load below the detectable limit on the skin surface and SC of drumsticks, respectively. Addition of LA seems to increase the microbial killing capacity of aqueous O3 with average differences of 0.3-log10/cm2 (P = 0.08) and 0.2-log10/cm2 (P = 0.12) on the skin surface using soaking and spraying approaches, respectively. Aqueous O3 did not cause any significant changes in the drumstick skin color. The Salmonella load of < 4.5-log10/cm2 was a strong predictor for the reduction rate (P < 0.001, R 2 = 0.64). These results provide important information that helps the poultry processing facilities for selecting the optimal operational strategy of O3 as an effective antimicrobial.

Characterization and Prevalence of Campylobacter spp. From Broiler Chicken Rearing Period to the Slaughtering Process in Eastern China

Campylobacter is one of the most important foodborne pathogens worldwide, and poultry is regarded as the main reservoir of Campylobacter. The contamination of Campylobacter in broiler chickens at the farm level is closely related to the transmission of Campylobacter in the poultry production chain. This study identified 464 Campylobacter isolates from 1,534 samples from broiler rearing period and slaughtering process including 233 Campylobacter jejuni isolates and 231 Campylobacter coli isolates. We have observed a dynamic distribution of Campylobacter during broiler chicken production, that 66.3% of Campylobacter isolates were C. jejuni during broiler rearing period, while C. coli occupied 60.4% of Campylobacter isolates during the broiler slaughtering process. A tag-label method allowed us to track the dynamic of Campylobacter in each broiler chicken from 31-day age at rearing to the partition step in the slaughterhouse. At the 31-day during rearing, 150 broiler chicken were labeled, and was tracked for Campylobacter positive from rearing period to slaughtering process. Among the labeled broiler, 11 of the tracking broiler samples were able to detect Campylobacter from rearing period to slaughtering. All Campylobacter isolates from the 11 tracking samples were sequenced and analyzed. C. jejuni isolates were divided into four STs and C. coli isolates were divided into six STs. Isolates with identical core genome were observed from the same tag-labeled samples at different stages indicating a vertical transmission of Campylobacter in the early broiler meat production. Meanwhile, the core genome analysis elucidated the cross-contamination of Campylobacter during the rearing period and the slaughtering process. The virulotyping analysis revealed that all C. jejuni isolates shared the same virulotypes, while C. coli isolates were divided into three different virulotypes. The antimicrobial resistance gene analysis demonstrated that all Campylobacter isolates contained at least two antibiotic resistance genes (ARGs), and the ARG profiles were well-corresponding to each ST type. Our study observed a high prevalence of Campylobacter during the early chicken meat production, and further studies will be needed to investigate the diversity and transmission of Campylobacter in the poultry production chain.

Ozone-Based Interventions To Improve the Microbiological Safety and Quality of Poultry Carcasses and Parts: A Review

HIGHLIGHTS

Ozone treatment achieved microbial population reductions. Gaseous ozone was most commonly used on poultry parts. Carcasses were treated exclusively with aqueous ozone or ozonated water. Ozone treatment can extend poultry product shelf life without significant quality effects.