Effect of peracetic acid on Campylobacter in food matrices mimicking commercial poultry processing

Interventions to reduce Salmonella and Campylobacter during chilling and post-chilling stages of poultry processing: a systematic review and meta-analysis

Salmonella and Campylobacter are common bacterial hazards causing foodborne illnesses worldwide. A large proportion of Salmonella and Campylobacter illnesses are attributed to contaminated poultry products that are mishandled or under cooked. Processing interventions such as chilling and post-chill dip are critical to reducing microbial contamination of poultry. A comprehensive search of the literature published between 2000 and 2021 was conducted in the databases Web of Science, Academic Search Complete, and Academic OneFile. Studies were included if they were in English and investigated the effects of interventions against Salmonella and/or Campylobacter on whole carcasses and/or parts during the chilling or post-chill stages of poultry processing. Random-effects meta-analyses were performed using the "meta" package in the R programming language. Subgroup analyses were assessed according to outcome measure reported, microorganism tested, processing stage assessed, and chemical treatment used. The results included 41 eligible studies. Eighteen studies reported results of 28 separate interventions against Salmonella and 31 reported results of 50 separate interventions against Campylobacter. No significant difference (P> 0.05) was observed when comparing the combined mean difference of all interventions targeting Salmonella to the combined mean difference of all interventions targeting Campylobacter or when comparing chilling times within each pathogen subgroup. For analyses examining antimicrobial additives, peroxyacetic acid (PAA) had the largest reduction against Salmonella population regardless of chilling time (P< 0.05). PAA also had the largest reduction against Campylobacter population and prevalence during primary chilling (P< 0.01). Air chilling showed a lower reduction for Campylobacter than any immersion chilling intervention (P< 0.05). Chilling time and antimicrobial used during poultry processing had varying effects depending on the pathogen and outcome measure investigated (concentration or prevalence). High heterogeneity and low sample numbers in most analyses suggest that more high-quality research that is well-designed and has transparent reporting of methodology and results is needed to corroborate the results.

Antimicrobial Tolerance in Salmonella: Contributions to Survival and Persistence in Processing Environments

Salmonella remains a top bacterial pathogen implicated in several food-borne outbreaks, despite the use of antimicrobials and sanitizers during production and processing. While these chemicals have been effective, Salmonella has shown the ability to survive and persist in poultry processing environments. This can be credited to its microbial ability to adapt and develop/acquire tolerance and/or resistance to different antimicrobial agents including oxidizers, acids (organic and inorganic), phenols, and surfactants. Moreover, there are several factors in processing environments that can limit the efficacy of these antimicrobials, thus allowing survival and persistence. This mini-review examines the antimicrobial activity of common disinfectants/sanitizers used in poultry processing environments and the ability of Salmonella to respond with innate or acquired tolerance and survive exposure to persists in such environments. Instead of relying on a single antimicrobial agent, the right combination of different disinfectants needs to be developed to target multiple pathways within Salmonella.

Unveiling the mechanisms of peracetic acid activation by iron-rich sludge biochar for sulfamethoxazole degradation with wide adaptability

Advanced oxidation processes (AOPs) based on peracetic acid (PAA) has been extensively concerned for the degradation of organic pollutants. In this study, metallic iron-modified sludge biochar (Fe-SBC) was employed to activate PAA for the removal of sulfamethoxazole (SMX). The characterization results indicated that FeO and Fe2O3 were successfully loaded on the surface of the sludge biochar (SBC). Fe-SBC/PAA system achieved 92% SMX removal after 30 min. The pseudo-first-order kinetic reaction constant of the Fe-SBC/PAA system was 7.34 × 10-2 min-1, which was 2.4 times higher than the SBC/PAA system. The degradation of SMX was enhanced with increasing the Fe-SBC dosage and PAA concentration. Apart from Cl-, NO3- and SO42- had a negligible influence on the degradation of SMX. Quenching experiments and electron paramagnetic resonance (EPR) techniques identified the existence of reactive species, of which CH3C(O)OO•, 1O2, and O2•- were dominant reactive species in Fe-SBC/PAA system. The effect of different water matrices on the removal of SMX was investigated. The removal of SMX in tap water and lake water were 79% and 69%, respectively. Four possible pathways for the decay of SMX were presented according to the identification of oxidation products. In addition, following the ecological structure-activity relationship model (ECOSAR) procedure and the germination experiments with lettuce seeds to predict the toxicity of the intermediates. The acute and chronic ecotoxicity of SMX solution was dramatically diminished by processing with Fe-SBC/PAA system. In general, this study offered a prospective strategy for the degradation of organic pollutants.

Identification of pH-specific protein expression responses by Campylobacter jejuni strain NCTC 11168

In this study a data dependent acquisition label-free based proteomics approach was used to identify pH-dependent proteins that respond in a growth phase independent manner in C. jejuni reference strain NCTC 11168. NCTC 11168 was grown within its pH physiological normal growth range (pH 5.8, 7.0 and 8.0, μ = ∼0.5 h^-1) and exposed to pH 4.0 shock for 2 hours. It was discovered that gluconate 2-dehydrogenase GdhAB, NssR-regulated globins Cgb and Ctb, cupin domain protein Cj0761, cytochrome c protein CccC (Cj0037c), and phosphate-binding transporter protein PstB all show acidic pH dependent abundance increases but are not activated by sub-lethal acid shock. Glutamate synthase (GLtBD) and the MfrABC and NapAGL respiratory complexes were induced in cells grown at pH 8.0. The response to pH stress by C. jejuni is to bolster microaerobic respiration and at pH 8.0 this is assisted by accumulation of glutamate the conversion of which could bolster fumarate respiration. The pH dependent proteins linked to growth in C. jejuni NCTC 11168 aids cellular energy conservation maximising growth rate and thus competitiveness and fitness.

Spoilage Bacteria Counts on Broiler Meat at Different Stages of Commercial Poultry Processing Plants That Use Peracetic Acid

In poultry processing, spoilage microbes are persistent microorganisms, which affect the quality of broiler meat. Peracetic acid (PAA) is the most common antimicrobial used by commercial processing plants, which can reduce the prevalence of these microbes. The goal of this study was to determine the concentrations of aerobic bacteria, coliforms, lactic acid bacteria, and Pseudomonas on broiler meat in processing plants that use peracetic acid in various concentrations as the primary antimicrobial. Samples were collected from three processing plants at five processing steps: post-pick (defeathering), pre-chill, post-chill, mechanically deboned meat (MDM), and drumsticks. Samples were rinsed in buffered peptone water for bacteria isolation. Over six log CFU/sample of aerobic plate counts (APC), lactic acid bacteria, and coliforms were detected on post-pick samples. All spoilage bacteria were reduced to nondetectable levels on post-chill samples (p < 0.001). However, the presence of all bacteria on mechanically deboned meat (MDM) samples indicated varying degrees of cross contamination from post-chill and MDM samples. These results suggest PAA effectively reduces spoilage microbes in chilling applications irrespective of differences in PAA concentrations. However, due to the levels of spoilage microbes detected in MDM, it may be worth investigating the potential interventions for this stage of processing.

Campylobacter Biofilms: Potential of Natural Compounds to Disrupt Campylobacter jejuni Transmission

Microbial biofilms occur naturally in many environmental niches and can be a significant reservoir of infectious microbes in zoonotically transmitted diseases such as that caused by Campylobacter jejuni, the leading cause of acute human bacterial gastroenteritis world-wide. The greatest challenge in reducing the disease caused by this organism is reducing transmission of C. jejuni to humans from poultry via the food chain. Biofilms enhance the stress tolerance and antimicrobial resistance of the microorganisms they harbor and are considered to play a crucial role for Campylobacter spp. survival and transmission to humans. Unconventional approaches to control biofilms and to improve the efficacy of currently used antibiotics are urgently needed. This review summarizes the use plant- and microorganism-derived antimicrobial and antibiofilm compounds such as essential oils, antimicrobial peptides (AMPs), polyphenolic extracts, algae extracts, probiotic-derived factors, d-amino acids (DAs) and glycolipid biosurfactants with potential to control biofilms formed by Campylobacter, and the suggested mechanisms of their action. Further investigation and use of such natural compounds could improve preventative and remedial strategies aimed to limit the transmission of campylobacters and other human pathogens via the food chain.

Peracetic Acid-Ruthenium(III) Oxidation Process for the Degradation of Micropollutants in Water

This paper presents an advanced oxidation process (AOP) of peracetic acid (PAA) and ruthenium(III) (Ru(III)) to oxidize micropollutants in water. Studies of PAA-Ru(III) oxidation of sulfamethoxazole (SMX), a sulfonamide antibiotic, in 0.5-20.0 mM phosphate solution at different pH values (5.0-9.0) showed an optimum pH of 7.0 with a complete transformation of SMX in 2.0 min. At pH 7.0, other metal ions (i.e., Fe(II), Fe(III), Mn(II), Mn(III), Co(II), Cu(II), and Ni(II)) in 10 mM phosphate could activate PAA to oxidize SMX only up to 20%. The PAA-Ru(III) oxidation process was also unaffected by the presence of chloride and carbonate ions in solution. Electron paramagnetic resonance (EPR) measurements and quenching experiments showed the dominant involvement of the acetyl(per)oxyl radicals (i.e., CH₃C(O)O^• and CH₃C(O)OO^•) for degrading SMX in the PAA-Ru(III) oxidation process. The transformation pathways of SMX by PAA-Ru(III) were proposed based on the identified intermediates. Tests with other pharmaceuticals demonstrated that the PAA-Ru(III) oxidation system could remove efficiently a wide range of pharmaceuticals (9 compounds) in the presence of phosphate ions in 2.0 min at neutral pH. The knowledge gained herein on the effective role of Ru(III) to activate PAA to oxidize micropollutants may aid in developing Ru(III)-containing catalysts for PAA-based AOPs.

Antimicrobial effects of sophorolipid in combination with lactic acid against poultry-relevant isolates

The objective of this study was to evaluate the antibacterial effect of sophorolipid in combination with lactic acid against relevant bacteria isolated from the poultry industry. Staphylococcus aureus, Listeria monocytogenes, Salmonella enterica, and Escherichia coli were isolated from chicken meat and antibacterial tests with sophorolipid and lactic acid were performed. Checkerboard, time-kill, and scanning electron microscopy analyses were used to confirm the antibacterial action and the combined effects. Although no inhibitory effects were observed for E. coli and Salmonella, these compounds presented antibacterial activity against L. monocytogenes and S. aureus. Additionally, sophorolipid and lactic acid were not cytotoxic at the concentrations used in the tests. The combination of sophorolipid and lactic acid resulted in an additive interaction, reducing the concentration of the active compounds needed for effectiveness against S. aureus and L. monocytogenes, to 50% and 75%, respectively. These findings lead to the possibility of developing a new, sustainable, and natural antimicrobial solution that is considered noncytotoxic and has wide applicability in the poultry industry to reduce substantial losses in this sector.

Bactericidal effect of glycerol monolaurate complex disinfectants on Salmonella of chicken

Glycerol monolaurate (GML) is a monoglycerol ester of the fatty lauric acids, which has a wide-spectrum antimicrobial capacity, but fails to inactivate Gram-negative bacteria, especial Salmonella. To enhance the population reduction rate of GML for Salmonella, this reagent was combined with three disinfectants: lactic acid (LA), cetylpyridinium chloride (CPC), and trisodium phosphate (TSP), which can present acid, neutral, and alkaline in solution, respectively. The results showed that the 1% GML and a complex disinfectant (0.5% GML-0.025% LA) could powerfully inactivate Salmonella. Their population reduction rates respectively were able to achieve 99.92% and 98.29% with the vortex treatment, indicating that the vortex treatment could improve GML to destruct the outer membrane of Salmonella. During the simulation test of the soaking and rinse processing of chicken, for a short time (0 h), the effect of 0.5% GML-0.025% LA compound was better and more suitable for instantaneous inactivation than others, while for a long time (4 h), 1% GML exhibited a better bactericidal effect, which indicated it to be more suitable for long-term bacteriostasis. The characterization of color and texture for chicken samples were determined using Colormeter Ci7600, TA.XT Plus and Hyper-spectral Imager, which demonstrated that all samples treated by these complex disinfectants were not significantly different from untreated group. In conclusion, GML is a potential and superior disinfectant for the chicken process.

Assessment of Stabilized Hydrogen Peroxide for Use in Reducing Campylobacter Levels and Prevalence on Broiler Chicken Wings

ABSTRACT

Poultry processing establishments use antimicrobial aids on broiler parts to minimize Campylobacter contamination. A silver-stabilized hydrogen peroxide (SHP) product was assessed for use as an antimicrobial processing aid. In a series of experiments, wing segments with skin were inoculated with 103 to 107 cells of Campylobacter coli, followed by treatment with SHP at 15,000 or 30,000 mg/L, peroxyacetic acid (PAA) at 300 or 3,000 mg/L (parts per million), or water. Each treatment was applied by either dip or spray. Rinsates from each wing segment were analyzed for direct counts and prevalence of Campylobacter. Treatment with SHP or PAA significantly reduced Campylobacter levels compared with water controls by up to 2.22 log CFU/mL. At high inoculum levels (106 to 107), SHP and PAA applied by dip had up to 1.27 log CFU/mL further reductions of Campylobacter levels compared with spray-treated wing segments. Additionally, wing drumettes were observed to retain higher levels and prevalence of Campylobacter recovery compared with wing flats at a low inoculation level (103). The results indicated that there was no carryover effect of SHP (same day versus 24 h) and dip treatment with SHP or PAA decreased Campylobacter recovery on broiler chicken wing segments compared with a water control. Although a 2-log reduction was modest, SHP had similar efficacy as the commonly used processing aid PAA. SHP shows potential for further investigation as an antimicrobial processing aid for use on poultry parts.

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