Antimicrobial activity of decontamination treatments for poultry carcasses: A literature survey

Added insult to injury? The response of meat-associated pathogens to proposed antimicrobial interventions

Modern requirements for 'green label' meat products have led to the design of novel antimicrobial innovations which prioritise quality, safety and longevity. Plasma-functionalised water (PFW), ultraviolet light and natural antimicrobial compositions have been investigated and optimised for control of foodborne pathogens like Campylobacter jejuni and Salmonella enterica serovar Typhimurium. However, given the adaptive mechanisms present in bacteria under external stresses, it is imperative to understand the effect that sublethal treatment may have on the bacterial transcriptome. In this study, Salmonella Typhimurium and C. jejuni were treated with sublethal doses of ultraviolet light, a citrus juice/essential oil marinade, and 'spark' or 'glow' cold plasma generation system-produced PFW. Immediately after treatment, cells were lysed and RNA was extracted and purified. mRNA was converted to cDNA by reverse transcription-PCR and sequenced by an Illumina MiSeq® system. Sequences were filtered and analysed using the Tuxedo workflow. Sublethal treatment of Campylobacter jejuni and Salmonella Typhimurium led to increased immediate cellular and metabolic activity, as well as diversification in protein and metabolic functioning. There was further expression of pathogenesis and virulence-associated traits associated with spark PFW and marinade treatment of Salmonella Typhimurium. However, similar concerns were not raised with glow PFW or UV-treated samples. This study provides science-based evidence of the efficacy of multi-hurdle antimicrobial system using green-label marinades and PFW or UV to inactivate pathogens without upregulating virulence traits in surviving cells. This study will inform policymakers and food industry stakeholders and reinforces the need to incorporate in-line novel technologies to ensure consumer safety. KEY POINTS: • Salmonella and C. jejuni showed increased cell activity in immediate response to stress. • Virulence genes showed increased expression when treated with natural antimicrobials and sPFW. • Reduced immediate transcriptomic response to gPFW and UV treatment indicates lower risk.

Microbial contamination pathways in a poultry abattoir provided clues on the distribution and persistence of Arcobacter spp

The consumption of contaminated poultry meat is a significant threat for public health, as it implicates in foodborne pathogen infections, such as those caused by Arcobacter. The mitigation of clinical cases requires the understanding of contamination pathways in each food process and the characterization of resident microbiota in the productive environments, so that targeted sanitizing procedures can be effectively implemented. Nowadays these investigations can benefit from the complementary and thoughtful use of culture- and omics-based analyses, although their application in situ is still limited. Therefore, the 16S-rRNA gene-based sequencing of total DNA and the targeted isolation of Arcobacter spp. through enrichment were performed to reconstruct the environmental contamination pathways within a poultry abattoir, as well as the dynamics and distribution of this emerging pathogen. To that scope, broiler's neck skin and caeca have been sampled during processing, while environmental swabs were collected from surfaces after cleaning and sanitizing. Metataxonomic survey highlighted a negligible impact of fecal contamination and a major role of broiler's skin in determining the composition of the resident abattoir microbiota. The introduction of Arcobacter spp. in the environment was mainly conveyed by this source rather than the intestinal content. Arcobacter butzleri represented one of the most abundant species and was extensively detected in the abattoir by both metataxonomic and enrichment methods, showing higher prevalence than other more thermophilic Campylobacterota. In particular, Arcobacter spp. was recovered viable in the plucking sector with high frequency, despite the adequacy of the sanitizing procedure.IMPORTANCEOur findings have emphasized the persistence of Arcobacter spp. in a modern poultry abattoir and its establishment as part of the resident microbiota in specific environmental niches. Although the responses provided here are not conclusive for the identification of the primary source of contamination, this biogeographic assessment underscores the importance of monitoring Arcobacter spp. from the early stages of the production chain with the integrative support of metataxonomic analysis. Through such combined detection approaches, the presence of this pathogen could be soon regarded as hallmark indicator of food safety and quality in poultry slaughtering.

Recent advancements in the utilization of ultrasonic technology for the curing of processed meat products: A comprehensive review

Curation meat products involves multiple stages, including pre-curing processing (thawing, cleaning, and cutting), curing itself, and post-curing processing (freezing, and packaging). Ultrasound are nonthermal processing technology widely used in food industry. This technology is preferred because it reduces the damages caused by traditional processing techniques on food, while simultaneously improving the nutritional properties and processing characteristics of food. The utilization of ultrasonic-assisted curing technology has attracted significant attention within the realm of meat product curing, encouraging extensive research efforts. In terms of curing meat products, ultrasonic-assisted curing technology has been widely studied due to its advantages of accelerating the curing speed, reducing nutrient loss, and improving the tenderness of cured meats. Therefore, this article aims to comprehensively review the application and mechanism of ultrasound technology in various stages of meat product curing. Furthermore, it also elaborates the effects of ultrasonic-assisted curing on the tenderness, water retention, and flavor substances of the meat products during the curing process. Besides, the implication of the ultrasound in the processing of meat curation plays a potent role together with other technologies or methods. The use of ultrasound technology in the process of meat curation was analyzed, which might be a theoretical insight for the industrialization prospects of the meat product.

Zoonotic sources and the spread of antimicrobial resistance from the perspective of low and middle-income countries

BACKGROUND

Antimicrobial resistance is an increasing challenge in low and middle-income countries as it is widespread in these countries and is linked to an increased mortality. Apart from human and environmental factors, animal-related drivers of antimicrobial resistance in low- and middle-income countries have special features that differ from high-income countries. The aim of this narrative review is to address the zoonotic sources and the spread of antimicrobial resistance from the perspective of low- and middle-income countries.

MAIN BODY

Contamination with extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli is highest in poultry (Africa: 8.9-60%, Asia: 53-93%) and there is a risk to import ESBL-producing E. coli through poultry meat in Africa. In aquacultures, the proportion of ESBL-producers among E. coli can be high (27%) but the overall low quality of published studies limit the general conclusion on the impact of aquacultures on human health. ESBL-producing E. coli colonization of wildlife is 1-9% in bats or 2.5-63% birds. Since most of them are migratory animals, they can disperse antimicrobial resistant bacteria over large distances. So-called 'filth flies' are a relevant vector not only of enteric pathogens but also of antimicrobial resistant bacteria in settings where sanitary systems are poor. In Africa, up to 72.5% of 'filth flies' are colonized with ESBL-producing E. coli, mostly conferred by CTX-M (24.4-100%). While methicillin-resistant Staphylococcus aureus plays a minor role in livestock in Africa, it is frequently found in South America in poultry (27%) or pork (37.5-56.5%) but less common in Asia (poultry: 3%, pork: 1-16%).

CONCLUSIONS

Interventions to contain the spread of AMR should be tailored to the needs of low- and middle-income countries. These comprise capacity building of diagnostic facilities, surveillance, infection prevention and control in small-scale farming.

Fatal gastritis and enterocolitis due to concurrent Helicobacter pylori and Campylobacter jejuni infection in a captive cheetah (Acinonyxjubatus)

A 3.5-year-old female cheetah (Acinonyx jubatus) died after a 10-day history of anorexia, regurgitation and diarrhoea despite symptomatic therapy. At gross post-mortem examination, the stomach was blood-filled with mucosal thickening and multifocal ulcerations. The intestinal mucosa was thickened and reddened, and the intestinal lumen was filled with dark red to black pasty content. Gastric histological lesions were compatible with gastritis due to Helicobacter infection, which was confirmed by polymerase chain reaction. Histology of the intestines revealed a severe necrotizing neutrophilic enterocolitis with abundant intralesional curved to spiral bacteria, corresponding to Campylobacter jejuni, which were subsequently isolated from both small and large intestinal contents. No other intestinal pathogens were detected despite thorough investigations. These findings suggest that C. jejuni may have played an aetiological role in the enterocolitis. Such an association has not been previously reported in non-domestic felids.

Chicken Skin Decontamination of Thermotolerant Campylobacter spp. and Hygiene Indicator Escherichia coli Assessed by Viability Real-Time PCR

Thermotolerant Campylobacter spp. are fecal contaminants of chicken meat with serious implications for human health. E. coli is considered as hygiene indicator since, in contrast to Campylobacter. spp., the bacterium is generally present in the avian gut. Stress exposure may transiently cease bacterial division. Therefore, colony forming units (CFU) may underestimate the infection risk of pathogens. We developed a viability real-time PCR (v-qPCR) for the quantification of viable E. coli targeting the uidA gene, encoding β-glucuronidase, which is usually detected for phenotypic species identification. The short- and long-term effects of decontaminating chicken skin on the survival of both C. jejuni and an ESBL-producing E. coli were evaluated by CFU and v-qPCR. The results showed that freezing and storage in cool conditions are potentially underestimated by CFU but not by v-qPCR. The effect of treatment with peroxyacetic acid on survival was consistently detected by CFU and v-qPCR. v-qPCR analysis detected bacterial survival upon the application of lactic acid, which awaits further analysis. Interestingly, both bacteria showed similar kinetics of inactivation upon the application of reduction strategies, suggesting that E. coli might be a complementary hygiene indicator. We conclude that v-qPCR can improve food safety under the consideration of some limitations.

Stress response modulation: the key to survival of pathogenic and spoilage bacteria during poultry processing

The control of bacterial contaminants on meat is a key area of interest in the food industry. Bacteria are exposed to a variety of stresses during broiler processing which challenge bacterial structures and metabolic pathways causing death or sublethal injury. To counter these stresses, bacteria possess robust response systems that can induce shifts in the transcriptome and proteome to enable survival. Effective adaptive responses, such as biofilm formation, shock protein production and metabolic flexibility, require rapid induction and implementation at a cellular and community level to facilitate bacterial survival in adverse conditions. This review aims to provide an overview of the scientific literature pertaining to the regulation of complex adaptive processes used by bacteria to survive the processing environment, with particular focus on species that impact the quality and safety of poultry products like Campylobacter spp., Salmonella enterica and Pseudomonas spp.

Bio-Mapping Indicators and Pathogen Loads in a Commercial Broiler Processing Facility Operating with High and Low Antimicrobial Intervention Levels

The poultry industry in the United States has traditionally implemented non-chemical and chemical interventions against Salmonella spp. and Campylobacter spp. on the basis of experience and word-of-mouth information shared among poultry processors. The effects of individual interventions have been assessed with microbiological testing methods for Salmonella spp. and Campylobacter spp. prevalence as well as quantification of indicator organisms, such as aerobic plate counts (APC), to demonstrate efficacy. The current study evaluated the loads of both indicators and pathogens in a commercial chicken processing facility, comparing the “normal chemical”, with all chemical interventions turned-on, at typical chemical concentrations set by the processing plant versus low-chemical process (“reduced chemical”), where all interventions were turned off or reduced to the minimum concentrations considered in the facility’s HACCP system. Enumeration and prevalence of Salmonella spp. and Campylobacter spp. as well as indicator organisms (APC and Enterobacteriaceae—EB) enumeration were evaluated to compare both treatments throughout a 25-month sampling period. Ten locations were selected in the current bio-mapping study, including live receiving, rehanger, post eviscerator, post cropper, post neck breaker, post IOBW #1, post IOBW #2, prechilling, post chilling, and parts (wings). Statistical process control parameters for each location and processing schemes were developed for each pathogen and indicator evaluated. Despite demonstrating significant statistical differences between the normal and naked processes in Salmonella spp. counts (“normal” significantly lower counts than the “reduced” at each location except for post-eviscerator and post-cropper locations), the prevalence of Salmonella spp. after chilling is comparable on both treatments (~10%), whereas for Campylobacter spp. counts, only at the parts’ location was there significant statistical difference between the “normal chemical” and the “reduced chemical”. Therefore, not all chemical intervention locations show an overall impact on Salmonella spp. or Campylobacter spp., and certain interventions can be turned off to achieve the same or better microbial performance if strategic intervention locations are enhanced.

Dietary Inclusion of a Saccharomyces cerevisiae-Derived Postbiotic Is Associated with Lower Salmonella enterica Burden in Broiler Chickens on a Commercial Farm in Honduras

Postbiotic feed additives may aid foodborne pathogen reduction during poultry rearing. The study objective was to evaluate a postbiotic additive in parallel to an industry control diet and the subsequent associated burden of Salmonella enterica on a single, commercial broiler farm in Honduras. Twelve houses were matched and assigned the standard diet (CON) or standard diet plus postbiotic (SCFP). New litter was placed in each house and retained across flock cycles with sampling prior to each chick placement and three consecutive rearing cycles. At ~33–34 days, 25 ceca were collected on-farm from each house, treatment, and cycle. Salmonella prevalence in litter for CON (30.6%) and SCFP (27.8%) were equivalent; however, Salmonella load within positive samples was lower (p = 0.04) for SCFP (3.81 log10 MPN/swab) compared to CON (5.53 log10 MPN/swab). Cecal prevalence of Salmonella was lower (p = 0.0006) in broilers fed SCFP (3.4%) compared to CON (12.2%). Salmonella load within positive ceca were numerically reduced (p = 0.121) by 1.45 log10 MPN/g for SCFP (2.41 log10 MPN/g) over CON (3.86 log10 MPN/g). Estimated burden was lower (p = 0.003) for SCFP flocks (3.80 log10 MPN) compared to CON (7.31 log10 MPN). These data demonstrate the preharvest intervention potential of postbiotics to reduce Salmonella enterica in broiler chickens.

Improved microbial and sensory quality of chicken meat by treatment with lactic acid, organic acid salts and modified atmosphere packaging

Microbial contamination and growth play important roles in spoilage and quality loss of raw poultry products. We evaluated the suitability of three commercially available organic acid based antimicrobial compounds, Purac FCC80 (l-lactic acid), Verdad N6 (buffered vinegar fermentate) and Provian K (blend of potassium acetate and diacetate) to prevent growth of the innate microbiota, reduce spoilage and enhance the sensory quality of raw chicken under vacuum, high CO₂ (60/40% CO₂/N₂), and high O₂ (75/25% O₂/CO₂) modified atmosphere (MA) storage conditions. Solutions were applied warm (50 °C) or cold (4 °C) to reflect treatments prior to (Prechill) or after (Postchill) cooling of chicken carcasses, respectively. Single postchill treatments of raw chicken wings with 5% Verdad N6 or Provian K solutions and MA storage enabled complete growth inhibition during the first seven days of storage before growth resumed. Enhanced bacterial control was obtained by combining Prechill lactic acid and Postchill Verdad N6 or Provian K treatments which indicated initial reductions up to 1.1 log and where total bacterial increase after 20 days storage was limited to 1.8-2.1 log. Antibacterial effects were dependent on the concentration of the inhibiting salts used, pH and the storage conditions. Bacterial community analyses showed increased relative levels of Gram-positive bacteria and with reductions of potential spoilage organisms in samples treated with the organic acid salts Verdad N6 and Provian K. Sensory analyses of raw, treated wings showed prominent lower scores in several spoilage associated odour attributes when compared with untreated chicken wings after 13 days storage. For heat-treated chicken, only minor differences for 22 tested attributes were detected between seven antimicrobial treatments and untreated control chicken. Immersion in commercially available organic acid/salt solutions combined with MA storage can reduce bacterial levels, improve microbial and sensory quality, and potentially improve shelf life and reduce food waste of chicken products.

Evidence of sheep and abattoir environment as important reservoirs of multidrug resistant Salmonella and extended-spectrum beta-lactamase Escherichia coli

The increase in antimicrobial-resistant (AMR) foodborne pathogens, including E. coli and Salmonella in animals, humans, and the environment, is a growing public health concern. Among animals, cattle, pigs, and chicken are reservoirs of these pathogens worldwide. There is a knowledge gap on the prevalence and AMR of foodborne pathogens in small ruminants (i.e., sheep and goats). This study investigates the prevalence and antimicrobial resistance of extended-spectrum beta-lactamase (ESBL) E. coli and Salmonella from sheep and their abattoir environment in North Carolina. We conducted a year-round serial cross-sectional study and collected a total of 1128 samples from sheep (n = 780) and their abattoir environment (n = 348). Sheep samples consisted of feces, cecal contents, carcass swabs, and abattoir resting area feces. Environmental samples consisted of soil samples, lairage swab, animal feed, and drinking water for animals. We used CHROMAgar EEC with 4 μg/ml of Cefotaxime for isolating ESBL E. coli, and ESBL production was confirmed by double-disk diffusion test. Salmonella was isolated and confirmed using standard methods. All of the confirmed isolates were tested against a panel of 14 antimicrobials to elucidate susceptibility profiles. The prevalence of ESBL E. coli and Salmonella was significantly higher in environmental samples (47.7% and 65.5%) compared to the sheep samples (19.5% and 17.9%), respectively (P < 0.0001). We recovered 318 ESBL E. coli and 368 Salmonella isolates from sheep and environmental samples. More than 97% (310/318) of ESBL E. coli were multidrug-resistant (MDR; resistant to ≥3 classes of antimicrobials). Most Salmonella isolates (77.2%, 284/368) were pansusceptible, and 10.1% (37/368) were MDR. We identified a total of 24 different Salmonella serotypes by whole genome sequencing (WGS). The most common serotypes were Agona (19.8%), Typhimurium (16.2%), Cannstatt (13.2%), Reading (13.2%), and Anatum (9.6%). Prevalence and percent resistance of ESBL E. coli and Salmonella isolates varied significantly by season and sample type (P < 0.0001). The co-existence of ESBL E. coli in the same sample was associated with increased percent resistance of Salmonella to Ampicillin, Chloramphenicol, Sulfisoxazole, Streptomycin, and Tetracycline. We presumed that the abattoir environment might have played a great role in the persistence and dissemination of resistant bacteria to sheep as they arrive at the abattoir. In conclusion, our study reaffirms that sheep and their abattoir environment act as important reservoirs of AMR ESBL E. coli and MDR Salmonella in the U.S. Further studies are required to determine associated public health risks.

Effect of ultrasound and chlorine dioxide on Salmonella Typhimurium and Escherichia coli inactivation in poultry chiller tank water

This study evaluated the application of ultrasound alone or combined with chlorine dioxide (ClO₂) for Salmonella Typhimurium and Escherichia coli inactivation in poultry processing chiller tank water. A Full Factorial Design (FFD) 2² was conducted for each microorganism to evaluate the effect of ultrasound exposure time (x₁: 1 to 9 min; fixed: 37 kHz; 330 W; 25 °C) using a bath, and ClO₂ concentration (x₂: 1 to 17 mg L^-1) on microorganism count expressed in log CFU mL^-1 in distilled water. Variable x₂ had a negative effect on Salmonella Typhimurium (-5.09) and Escherichia coli (-2.00) count, improving the inactivation; while a x₁ increase present no inactivation improvement, explaining the use of x₁ lower level (1 min) and x₂ higher level (17 mg L^-1). The best condition for microorganism inactivation based on FFD was evaluated in chiller tank water (with organic matter) at 25, 16, and 4 °C; x₁ was kept (1 min), however x₂ was adjusted to obtain the same residual free chlorine (2.38 mg L^-1) considering the ClO₂ consumption by organic matter, achieving the value of 30 mg L^-1. An inactivation of 49% and 31% were observed for Salmonella Typhimurium and Escherichia coli. When ultrasound was replaced by a simple agitation in the presence of ClO₂, there was no inactivation for both microorganisms. Moreover, at poultry carcass pre-chilling (16 °C) and chilling (4 °C) conditions, the synergism of ultrasound combined with ClO₂ was more pronounced, with microorganisms' reductions up to 100%.

Systematic-review and meta-analysis on effect of decontamination interventions on prevalence and concentration of Campylobacter spp. during primary processing of broiler chickens

Scientific advances in pathogen decontamination offer great potential to reduce Campylobacter spp. during primary processing. The aim of this study was to collate data from eligible studies using systematic review, meta-analysis followed by meta-regression. Random effect meta-analysis revealed heterogenous (τ² = 0.6, I² = 98 %) pooled reduction in Campylobacter concentration of 0.6 log₁₀ CFU/carcass and a decrease in relative risk of Campylobacter spp. prevalence in broiler carcasses by 57.2 %. Decontamination interventions during Inside-Outside-Carcass-Wash were most effective on concentration (0.8 log₁₀ CFU/carcass) while those during evisceration were most effective on prevalence (78.0 % decrease in relative risk). Physical decontamination was more effective on Campylobacter prevalence (68.7 % decrease in relative risk) compared chemical treatment (30.3 %). Application through immersion was superior on Campylobacter concentration (0.9 log₁₀ CFU/carcass odds reduction) to spraying (0.5 log₁₀ CFU/carcass odds reduction). Publication bias and small study effect were observed in trials on Campylobacter prevalence but not for concentration. The meta-regression revealed four and seven potential modifier variables for concentration and prevalence respectively. This meta-analysis provides an overview of the expected magnitude in Campylobacter spp. concentration and prevalence with application of decontamination interventions on broiler carcasses along the slaughter process and forms a basis of quantitative microbial risk assessment and derivation of intervention measures. Even though modest microbial concentration reduction is reported there was a large decrease in contamination prevalence during processing interventions.

A systematic review and meta-analysis of the efficacy of processing stages and interventions for controlling Campylobacter contamination during broiler chicken processing

Systematic review and meta-analysis were conducted to quantify the effects of processing stages and interventions on the prevalence and concentration of Campylobacter on broiler carcasses. To comprehensively capture relevant evidence, six databases were searched using the keywords "Campylobacter" and "broiler chicken." The literature search yielded 10,450 unique citations, and after applying predetermined inclusion and exclusion criteria, 72 and 53 relevant citations were included in meta-analyses for processing stages and interventions, respectively. As the two primary outcomes, log reduction and prevalence changes were estimated for each stage or intervention using a random-effects meta-analysis approach whenever possible. The outcome-level quality assessment was conducted following the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. The analysis revealed that scalding and chilling majorly reduces the prevalence and concentration of Campylobacter. Immersion chilling reduces the concentration regardless of chemical additives, but its effect on prevalence is not conclusive. The effects of carcass washing applications remain uncertain due to the inconsistency and imprecision of both outcomes. Defeathering and evisceration were identified as stages that can increase both prevalence and concentration. Both chemical and physical processing interventions provide limited efficacy in concentration and prevalence reduction. Major limitations of the review were inconsistency and imprecision at the outcome level and reporting issues and data gaps at the study level. The results are expected to inform quantitative microbial risk assessment model development and support evidence-based decision-making.

The fate of sodium chlorite in simulated gastric and intestinal fluids and residues of chlorate in broiler chickens after oral administration of sodium chlorite

The fate of sodium [³⁶Cl]chlorite in simulated intestinal fluids and residues of chlorate in broiler chickens fed 0, 10, 100, or 1000 mg•kg^-1 of dietary sodium chlorite for 7 days was determined. [³⁶Cl]Chlorite was stable in water and simulated intestinal fluid during 6 h incubations but was rapidly degraded to chlorine dioxide, sodium chloride, and sodium chlorate in simulated gastric fluids. Addition of starch, citrate, or soybean shifted the relative proportions of chloroxyanions formed; addition of ferrous chloride caused quantitative formation of sodium chloride in gastric and intestinal fluids. [³⁶Cl]Chlorite underwent reductive transformation when fortified into chicken serum. Residues of chlorate in broiler chickens ranged from 3.5 to 374 ng•g^-1 in gizzard, were <6.8 to 126 ng•g^-1 in liver and were <7.2 to 190 ng•g^-1 in muscle when slaughtered with no withdrawal period. Data are presented suggesting that reductive processes govern the fate of chlorite when present in closed biological systems.

Using Risk–Benefit Analysis to Control Salmonella in Chicken Meat

We have created a risk–benefit analysis (RBA) model to assist in food safety decision-making by analyzing Salmonella control in Brazilian chicken meat. First, we described the issues in a risk profile and used a 5×5 matrix to rank the risks associated with Salmonella. We then classified the magnitude of benefits and costs of control measures using another matrix. Finally, we verified the beneficial effects of recommended control measures using Quantitative Microbiological Risk Assessment (QMRA). The RBA classified Salmonella contamination as risk 6, indicating that control measures should be taken in the short and medium terms. It also recommended the adoption of biosecurity measures on farms to reduce the prevalence of Salmonella in birds, better control of carcass washings and chiller tank management, and information placement on packages and campaigns to raise the awareness of the population about the need to control Salmonella contamination before consumption. On the other hand, it did not recommend better controls at scalding and defeathering. QMRA confirmed the beneficial effects of the recommended control measures. For example, as Salmonella prevalence in poultry increased from 4.04 per cent to 50 per cent, the risk of infection per serving also increased from 0.0080 to 0.071. Although better controls in washings and chiller tank management did not affect the risk of infection, it reduced Salmonella counts on carcasses. We assume that the presence of Salmonella on carcasses was due to improper thermal processing or cross-contamination, which increased the risk from 0.0080 to 0.015962. The RBA demonstrated the logic involved in the adoption of control measures, and this can be helpful in the risk management of food safety issues.

UV-C LED Irradiation Reduces Salmonella on Chicken and Food Contact Surfaces

Ultraviolet (UV-C) light-emitting diode (LED) light at a wavelength of 250–280 nm was used to disinfect skinless chicken breast (CB), stainless steel (SS) and high-density polyethylene (HD) inoculated with Salmonella enterica. Irradiances of 2 mW/cm² (50%) or 4 mW/cm² (100%) were used to treat samples at different exposure times. Chicken samples had the lowest Salmonella reduction with 1.02 and 1.78 Log CFU/cm² (p ≤ 0.05) after 60 and 900 s, respectively at 50% irradiance. Higher reductions on CB were obtained with 100% illumination after 900 s (>3.0 Log CFU/cm²). Salmonella on SS was reduced by 1.97 and 3.48 Log CFU/cm² after 60 s of treatment with 50% and 100% irradiance, respectively. HD showed a lower decrease of Salmonella, but still statistically significant (p ≤ 0.05), with 1.25 and 1.77 Log CFU/cm² destruction for 50 and 100% irradiance after 60 s, respectively. Longer exposure times of HD to UV-C yielded up to 99.999% (5.0 Log CFU/cm²) reduction of Salmonella with both irradiance levels. While UV-C LED treatment was found effective to control Salmonella on chicken and food contact surfaces, we propose three mechanisms contributing to reduced efficacy of disinfection: bacterial aggregation, harboring in food and work surface pores and light absorption by fluids associated with CB.

The changing microbiome of poultry meat; from farm to fridge

Chickens play host to a diverse community of microorganisms which constitute the microflora of the live bird. Factors such as diet, genetics and immune system activity affect this complex population within the bird, while external influences including weather and exposure to other animals alter the development of the microbiome. Bacteria from these settings including Campylobacter and Salmonella play an important role in the quality and safety of end-products from these birds. Further steps, including washing and chilling, within the production cycle aim to control the proliferation of these microbes as well as those which cause product spoilage. These steps impose specific selective pressures upon the microflora of the meat product. Within the next decade, it is forecast that poultry meat, particularly chicken will become the most consumed meat globally. However, as poultry meat is a frequently cited reservoir of zoonotic disease, understanding the development of its microflora is key to controlling the proliferation of important spoilage and pathogenic bacterial groups present on the bird. Whilst several excellent reviews exist detailing the microbiome of poultry during primary production, others focus on fate of important poultry pathogens such as Campylobacter and Salmonella spp. At farm and retail level, and yet others describe the evolution of spoilage microbes during spoilage. This review seeks to provide the poultry industry and research scientists unfamiliar with food technology process with a holistic overview of the key changes to the microflora of broiler chickens at each stage of the production and retail cycle.

Effect of lemongrass essential oil against multidrug-resistant Salmonella Heidelberg and its attachment to chicken skin and meat

Salmonella Heidelberg (S. Heidelberg) is a major pathogen implicated in foodborne outbreaks for which poultry products can serve as an epidemiological source. This study determined the efficacy of GRAS-status lemongrass essential oil (LGEO) against S. Heidelberg in vitro and on the pathogen's attachment to skin and meat. At first, employing in vitro assays, the effect of LGEO on multidrug-resistant S. Heidelberg multiplication and motility was examined. Biofilm inhibition and inactivation assays were also performed. The quorum-sensing modulating effect of LGEO was determined. In follow-up experiments, chicken skin or meat samples inoculated with S. Heidelberg were treated with various concentrations of LGEO at different time points at simulated scalding (54°C) and chilling (4°C) temperatures. The samples were incubated, and the surviving populations of S. Heidelberg were enumerated to determine if LGEO could be a potential processing aid in poultry operations. Duplicate samples were included in each treatment, and the experiments were repeated at least 3 times. Significant reductions of S. Heidelberg of at least 4.0 log₁₀ CFU/mL after 24 h in nutrient broth and poultry cecal contents was observed with 0.5% LGEO. Complete inhibition of motility, biofilm formation, and inactivation of pre-formed biofilms was observed with 0.15% LGEO (P ≤ 0.05). Concentrations of LGEO at 0.5% and 1% affected violacein production (P ≤ 0.05). On skin samples, all concentrations significantly reduced S. Heidelberg by 1.2 to 3.9 log₁₀ CFU/sample after 2 min at 54°C. We obtained a significant reduction of the pathogen in meat samples at 54°C and skin samples at 4°C with 2% LGEO. All concentrations significantly reduced S. Heidelberg from the treatment water kept at 4°C and 54°C (P ≤ 0.05). In conclusion, LGEO could potentially serve as a natural antimicrobial strategy in scalding and chilling waters to reduce S. Heidelberg during processing. However, additional studies are warranted before recommending its commercial use.

Effects of grape and pomegranate waste extracts on poultry carcasses microbial, chemical, and sensory attributes in slaughterhouse

Contamination of poultry carcasses is considered as a critical point in the evaluation of poultry meat safety. The present study aimed at determining the decontamination effects of natural antimicrobial derived from grape waste extract and pomegranate waste extract (GWE and PWE) on poultry carcasses in a slaughterhouse. Poultry carcasses were treated in chiller with concentrations of 0, 2, 4 and 6% of pomegranate and grape waste extracts. Pomegranate and grape waste extracts contained 432.20 and 328.43 mg GAE/g total phenolic compounds. These extracts showed significant antimicrobial effect on the main poultry bacteria in vitro. On the first day of cold storage, significant reduction in total bacterial counts (p < .05) was observed in treated carcasses. After 3 days of storage time, total bacteria, Staphylococcus aureus, and Escherichia coli reduced significantly (p < .05) compared to untreated samples. At sixth and ninth days of storage time, significant reduction in total volatile nitrogen (TVN), total bacteria counts, Staphylococcus aureus, coliforms, and Escherichia coli were observed. Sensory attributes in treated carcasses with PWE and GWE have been enhanced significantly compared to untreated during acceptable shelf time (p < .05). Based on the results, pomegranate and grape waste extracts can be used to preserve and improve the shelf life of the poultry carcasses close to the standard range until the ninth day of storage. Application of pomegranate and grape waste extracts in slaughterhouse could be considered as an environmentally, natural and safe decontamination intervention in integral food safety system.

On farm interventions to minimise Campylobacter spp. contamination in chicken

1. This review explores current and proposed on-farm interventions and assess the potential of these interventions against Campylobacter spp. 2. Interventions such as vaccination, feed/water-additives and, most importantly, consistent biosecurity, exhibit potential for the effective control of this pathogen and its dissemination within the food chain. 3. Due to the extensive diversity in the Campylobacter spp. genome and surface-expressed proteins, vaccination of poultry is not yet regarded as a completely effective strategy. 4. The acidification of drinking water through the addition of organic acids has been reported to decrease the risk of Campylobacter spp. colonisation in broiler flocks. Whilst this treatment alone will not completely protect birds, use of water acidification in combination with in-feed measures to further reduce the level of Campylobacter spp. colonisation in poultry may be an option meriting further exploration. 5. The use of varied types of feed supplements to reduce the intestinal population and shedding rate of Campylobacter spp. in poultry is an area of growing interest in the poultry industry. Such supplements include pro - and pre-biotics, organic acids, bacteriocins and bacteriophage, which may be added to feed and water. 6. From the literature, it is clear that a distinct, albeit not unexpected, difference between the performance of in-feed interventions exists when examined in vitro compared to those determined in in vivo studies. It is much more likely that pooling some of the discussed approaches in the in-feed tool kit will provide an answer. 7. Whilst on-farm biosecurity is essential to maintain a healthy flock and reduce disease transmission, even the most stringent biosecurity measures may not have sufficient, consistent and predictable effects in controlling Campylobacter spp. Furthermore, the combination of varied dietary approaches and improved biosecurity measures may synergistically improve control.

Electrochemically-Activated Water Presents Bactericidal Effect Against Salmonella Heidelberg Isolated from Poultry Origin

Salmonella spp. are among the most important pathogens in poultry farming, and Salmonella Heidelberg (SH) is one of the most frequent serotypes isolated in Brazil. SH has a zoonotic potential and stands out as a pathogen that is difficult to eliminate from the poultry chain due to its resistance to disinfectants. One alternative to traditional disinfectants is the electrochemically-activated water (ECA), a bactericidal compound produced from the electrolysis of salt and water. ECA generators produce a compound that consists of free chlorine, hypochlorous acid, and other free radicals. This alternative control method is safe for human health and reduces environmental contamination. The present study aimed at evaluating the efficacy of ECA against 30 SH isolates from poultry origin in scenarios that simulated the chiller environment (4°C, 5 and 50 parts per million [ppm], 5 and 40 min of exposure) and the cleaning and disinfection process (25°C, 200 ppm, 5 and 10 min of exposure). In the quantitative test, SH was susceptible to ECA. The mean bacterial counts decreased significantly compared to the control group, especially at 200 ppm. At this concentration, ECA inhibited the growth of almost 87% of the Salmonella strains, and the results showed a significant decrease in the mean bacterial counts for both exposure times (5 and 10 min). These findings demonstrate that ECA is effective against SH in vitro and it is a possible alternative to disinfection in the poultry industry for the control of this pathogen. However, in situ tests in the food industry are needed.

The prevalence of Campylobacter species in broiler flocks and their environment: assessing the efficiency of chitosan/zinc oxide nanocomposite for adopting control strategy

There is a growing trend to implement biosecurity measures in small commercial broiler flocks and trying to replace ineffective antimicrobial with alternative materials to interevent a strategy for the control of Campylobacter bacteria in these farms. This study was designed to determine the prevalence rate of Campylobacter spp. in broiler flocks and their environment. Thereafter, assess the efficiency of chitosan, zinc oxide nanoparticles (ZnO NPs), and chitosan/ZnO NPs composite against Campylobacter strains to adopt a novel control strategy based on the ability to use those nanocomposites. A total of 220 samples were collected from broiler flocks, their environment, and farm attendants that direct contact with birds. All samples were subjected to microbiological investigation for isolation, then molecular identification of bacteria using PCR. ZnO NPs and chitosan/ZnO NPs composite were synthesized then characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier-transform infrared spectrum (FT-IR), and X-ray diffraction (X-RD). The efficiency of testing compounds was examined against 30 strains of Campylobacter coli (C. coli) to determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The highest percentages of C. coli were isolated from the manure storage area, and broiler litter followed by flies, and feeders (66.7, 53.3, 40.0, and 33.3%, respectively). Both chitosan/ZnO NPs and ZnO NPs at a concentration of 0.5 μg/mL and 1.5 μg/mL, respectively showed complete efficiency (100%) against C. coli compared with chitosan compound. In conclusion, manure storage area and broiler litter represented the main reservoir of Campylobacter bacterial contaminant followed by flies in broiler poultry farms. Chitosan/ZnO NPs composite can be used in any biosecurity program of poultry farms as an alternative to ineffective antimicrobial agents.

Prioritization of Chicken Meat Processing Interventions on the Basis of Reducing the Salmonella Residual Relative Risk

Protecting public health by controlling Salmonella in chicken meat products continues to be a challenge to both industry and policymakers. Studies evaluating the combined use of commercially available antimicrobial interventions are scarce. The aim of this work was to develop a risk-based prioritization framework to rank chicken meat processing interventions that achieve the greatest Salmonella relative risk reduction. A baseline model characterizing the current U.S. broiler industry food safety intervention practices was created from direct observation of processes and expert elicitation. Results showed the combination of chlorine at the bird wash station and peroxyacetic acid at the on-line reprocessing and chill stages as the most common U.S. processing scenario. Irradiation at packaging and acidified sodium chlorite at evisceration were the most effective single processing interventions (98.8 and 91.6% risk reduction, respectively); however, no single intervention was able to comply with the current Food Safety and Inspection Service Salmonella postchill performance standards. The combination of peroxyacetic acid in at least one of the chicken processing stages with the current set of U.S. baseline interventions achieved >99% Salmonella relative risk reduction and ensured Food Safety and Inspection Service compliance. Adding more than one intervention to the U.S. current practice did not enhance (<2%) the overall Salmonella risk reduction. This study can help poultry processors to prioritize food safety interventions to maximize Salmonella reduction and public health protection.

The Efficacy of Sodium Bisulfate Salt (SBS) Alone and Combined With Peracetic Acid (PAA) as an Antimicrobial on Whole Chicken Drumsticks Artificially Inoculated With Salmonella Enteritidis

The presence of Salmonella spp. on poultry products is one of the leading causes of foodborne illness in the United States. Therefore, novel antimicrobial substances are being explored as potential interventions in poultry processing facilities. The objective of the current study was to evaluate the efficacy of varying concentrations of sodium bisulfate salt, SBS, alone or in combination with peracetic acid, PAA, in 15 s whole part dips. Ninety six drumsticks (4 replications, 8 treatments, 3 days) were inoculated separately in a 400 mL solution of nalidixic resistant (NA) Salmonella Enteritidis (10⁷ CFU/mL) and allowed to adhere for 60 to 90 min at 4°C for a final concentration of 10⁶ CFU/g. The experimental treatments included: a no treatment (control), and 15 s dips in 300 mL of tap water alone (TW) or with the addition of 1; 2; and 3% SBS; 1; 2; and 3% SBS+PAA. After treatment, drumsticks were stored at 4°C until microbial sampling was conducted. On d 0, l, and 3, drumsticks were rinsed in 150 mL of nBPW for 1 min, 100 μL of rinsate was serially diluted, spread plated on XLT4+NA (20 μg/mL), and incubated aerobically at 37°C for 24 h. Log-transformed counts were analyzed using a randomized complete block design (day) using One-Way ANOVA, polynomial contrasts, and pairwise comparisons with means being separated by Tukey's HSD with a significance level of P ≤ 0.05. A treatment by day interaction (P = 0.14071) was not substantial. Thus, the treatment effect was investigated separately by days. Over time, a linear trend was observed in S. Enteritidis concentration when SBS was increased (1 < 2 < 3%). The concentration of S. Enteritidis was different between 1% SBS and 1% SBS+PAA on d 0. However, the level of S. Enteritidis was not different among drumsticks treated in 2 and 3% SBS and 2 and 3% SBS+PAA across d 0, 1, 3. The application of 3% SBS alone or in combination with 200 ppm of PAA is capable of reducing the presence of Salmonella over a 3-d refrigeration period; potentially increasing the safety of poultry products for consumers.

Relative response of populations of Escherichia coli and Salmonella enterica to exposure to thermal, alkaline and acidic treatments

We evaluated the relative response of generic Escherichia coli (GEC), Shiga toxin-producing E. coli (STEC) and Salmonella enterica to heat, alkaline or acid treatments. GEC included strains from carcasses (n = 24) and trim (n = 25) at a small beef plant where no decontamination interventions are used and at a large plant where multiple decontamination interventions are used (carcass n = 25 and trim n = 25). STEC strains belonging to nine serogroups, included isolates from cattle (n = 53), beef (n = 16) and humans (n = 44). S. enterica strains belonging to 29 serotypes, included isolates from humans (n = 30), poultry (n = 26), pork (n = 10) and beef (n = 33). Strains were grown in Brain Heart Infusion (BHI) broth and subjected to the following treatments: 60 °C for 2 min, 5% lactic acid (pH 2.9) for 1 h at 4 °C, or NaOH (pH 11.0) for 2 h at 4 °C. Median log reductions of the GEC populations after heat, alkaline and acid treatment ranged from 2.3 to 3.8, 0.7 to 2.2 and 0.7 to 1.2 log CFU/mL, respectively. No statistically significant difference in reductions was observed between carcass GEC or trim GEC from the large or small plant, except for a greater reduction in trim GEC from the small plant. Median reductions of the STEC populations ranged from 3.3 to 3.5, 0.0 to 0.6, and 0.3 to 0.5 log CFU/mL after heat, alkaline and acid treatment, respectively. The median reductions were not dependent upon isolation source, except between STEC cattle and human isolates after alkaline treatment, where the reduction of the former was higher by 0.6 log unit. For the Salmonella populations, median log reductions ranged from 3.5 to 4.0, 1.7 to 2.4 and 3.7 to 4.1 log CFU/mL after heat, alkaline and acid treatment, respectively. The reductions were not isolation source related. The median log reductions were in the order GEC < STEC < Salmonella after heat treatment and STEC < GEC < Salmonella after alkaline or acid treatment. Overall, the relative response of GEC, STEC and Salmonella in the model system suggests that exposure to heat or pH-based decontamination interventions in meat plants is not associated with increased resistance among E. coli strains in these environments, and total E. coli counts on beef can be indicative of treatment efficacy for the control of Salmonella by heat, lactic acid and alkaline treatment and for the control of STEC subjected to heat.

The Effect of Organic Acid, Trisodium Phosphate and Essential Oil Component Immersion Treatments on the Microbiology of Cod (Gadus morhua) during Chilled Storage

Spoilage is a major issue for the seafood sector with the sale and exportation of fish limited by their short shelf-life. The immediate and storage effects of immersion (30 s at 20 °C) with 5% (w/v) citric acid (CA), 5% (v/v) lactic acid (LA), 5% (w/v) capric acid (CP) and 12% trisodium phosphate (TSP) (experiment 1) and essential oil components (EOC) (1% (v/v) citral (CIT), 1% (v/v) carvacrol (CAR), 1% (w/v) thymol (THY) and 1% (v/v) eugenol (EUG)) (experiment 2) on the concentrations of indicator (total viable counts (TVC) (mesophilic and psychrophilic) and total Enterobacteriaceae counts (TEC)), and spoilage organisms (Pseudomonas spp., lactic acid bacteria (LAB), Brochothrix thermosphacta, Photobacterium spp. and hydrogen sulphide producing bacteria (HSPB)) on cod (Gadus morhua) (stored aerobically at 2 °C) was investigated. There was no significant reduction for most treatment-bacteria combinations, with the following exceptions; TSP and TVC_m (time t = 6), TSP and TVC_p (t = 6), CP and LAB (t = 6, 8 and 10), CP and Br. thermosphacta (t = 4, 6, 8, 10, 14 and 16), TSP and Photobacterium spp. (t = 4), CAR and Br. thermosphacta (t = 6) and CAR and HSPB (t = 3, 6, 9, 12, 15 and 18). Although the majority of treatments did not significantly (P > 0.05) reduce bacterial counts, the limited success with CP and CAR warrants further investigation.

Effect of Succinic Acid on Elimination of Salmonella in Chicken Meat

The aim of this study was to determine the effect of selected concentrations of succinic acid on the survival of Salmonella on microbiological media and on the surfaces of chicken carcasses. Samples were inoculated with Salmonella serovars Enteritidis, Typhimurium, Hadar, Infantis, and Virchow. Each strain from each dilution was plated on nutrient agar without chemical substances (pH 6.75, control) or with 0.02% (pH 5.73), 0.05% (pH 4.77), 0.1% (pH 4.42), or 0.25% (pH 3.90) succinic acid. The addition of 0.25% succinic acid in agar medium completely inhibited the growth of all Salmonella strains tested. The 150 samples of broiler chicken breasts were immersed for 2 min in 80 mL of a 10⁷ CFU/mL Salmonella cocktail. The samples were then transferred to sterile beakers with 250 mL of 2 and 5% succinic acid for 5 min. With 2% succinic acid, Salmonella reductions (compared with the control) were 1.27 to 1.47 log CFU/g. With 5% succinic acid, reductions were 2.00 to 3.20 log CFU/g. The results indicate that it is possible to reduce the level of Salmonella on broiler chicken carcasses by immersing them in a 2% succinic acid solution.

Antimicrobial effect of copper surfaces on bacteria isolated from poultry meat

Poultry meat is a food product that usually carries high rates of microbial contamination, including foodborne pathogens. The poultry industry has established different systems to minimize these hazards. In recent years, extensive literature has demonstrated the antimicrobial activity of different contact surfaces made of copper to effectively reduce microbial loads. The aim of the present study was to evaluate the antibacterial effect of copper surfaces on the transmission of two foodborne pathogens – Salmonella enterica and Listeria monocytogenes – and a poultry native microbiota bacterial species – Enterobacter cloacae. We also evaluated the impact of the poultry meat matrix on the antimicrobial activity of a copper surface. Our results indicated that copper surfaces reduced the bacterial load quickly (<than 4 min) when the microorganisms were exposed to polished copper surfaces. Even when bacteria were inoculated on copper surfaces soiled with the organic matrix (washing water from poultry carcasses) and survival rates were significantly higher, an antimicrobial effect was still observed. Survival rates of two microorganisms simultaneously exposed to copper did not show significant differences. We found an antimicrobial effect over pathogenic and non-pathogenic microorganisms. Results suggest a potential role for copper surfaces in the control of microbiological hazards in the poultry industry.

Salmonella Cold Stress Response: Mechanisms and Occurrence in Foods

Since bacteria in foods often encounter various cold environments during food processing, such as chilling, cold chain distribution, and cold storage, lower temperatures can become a major stress environment for foodborne pathogens. Bacterial responses in stressful environments have been considered in the past, but now the importance of stress responses at the molecular level is becoming recognized. Documenting how bacterial changes occur at the molecular level may help to achieve the in-depth understanding of stress responses, to predict microbial fate when they encounter cold temperatures, and to design and develop more effective strategies to control pathogens in food for ensuring food safety. Microorganisms differ in responding to a sudden downshift in temperature and this, in turn, impacts their metabolic processes and can cause various structural modifications. In this review, the fundamental aspects of bacterial cold stress responses focused on cell membrane modification, DNA supercoiling modification, transcriptional and translational responses, cold-induced protein synthesis including CspA, CsdA, NusA, DnaA, RecA, RbfA, PNPase, KsgA, SrmB, trigger factors, and initiation factors are discussed. In this context, specific Salmonella responses to cold temperature including growth, injury, and survival and their physiological and genetic responses to cold environments with a focus on cross-protection, different gene expression levels, and virulence factors will be discussed.

Chicken fillets subjected to UV-C and pulsed UV light: Reduction of pathogenic and spoilage bacteria, and changes in sensory quality

We have compared the efficacy of continuous ultraviolet (UV-C) (254 nm) and pulsed UV light in reducing the viability of Salmonella Enteritidis, Listeria monocytogenes, Staphylococcus aureus, enterohemorrhagic Escherichia coli, Pseudomonas spp., Brochothrix thermospacta, Carnobacterium divergens, and extended-spectrum β-lactamase producing E. coli inoculated on chicken fillet surface. Fluences from 0.05 to 3.0 J/cm2 (10 mW/cm2, from 5 to 300 s) used for UV-C light resulted in average reductions from 1.1 to 2.8 log cfu/cm2. For pulsed UV light, fluences from 1.25 to 18.0 J/cm2 gave average reductions from 0.9 to 3.0 log cfu/cm2. A small change in the odor characterized as sunburnt and increased concentration of volatile compounds associated with burnt odor posed restrictions on the upper limit of UV treatment, however no sensory changes were observed after cooking the meat. Treatments under modified atmosphere conditions using a UV permeable top film gave similar or slightly lower bacterial reductions.

PRACTICAL APPLICATIONS

Ultraviolet (UV) light may be used for decontaminating the surface of food products and reduce viability of pathogenic and spoilage bacteria. Exposure of raw chicken fillet surface to various doses of continuous UV-C or pulsed UV light proposed in the present work represent alternatives for microbiological improvement of this product. Chicken fillets can be treated in intact packages covered with UV permeable top film, thus avoiding recontamination of the meat. UV-C light treatment is a low cost strategy with low maintenance, whereas pulsed UV light involves more elaborate equipment, but treatment times are short and less space is required. Both methods can be helpful for producers to manage the safety and quality of chicken fillets.