Antimicrobial Efficacy of a Sulfuric Acid and Sodium Sulfate Blend, Peroxyacetic Acid, and Cetylpyridinium Chloride against Salmonella on Inoculated Chicken Wings

Relative resistance of Salmonella serotypes (Typhimurium, Infantis, and Reading) to peroxyacetic acid on chicken wings

Peroxyacetic acid (PAA) is widely used as an antimicrobial in poultry processing. Recent salmonellosis outbreaks caused by Salmonella Infantis (SI) from chicken products and Salmonella Reading (SR) from turkey products have raised concerns about their enhanced resistance (compared to Salmonella Typhimurium [ST]) to commonly used antimicrobial interventions such as PAA. The objective of this research was to evaluate the efficacy of PAA against Salmonella serotypes (Typhimurium, Infantis and Reading), effect on product color and decomposition of PAA at different pH levels. Fresh chicken wings (0.45 kg) were inoculated with a cocktail (ca. 6 log CFU/mL) of nalidixic acid resistant ST, rifampicin resistant SI and kanamycin resistant SR. Inoculated chicken wings were immersed in PAA solutions (100 or 500 ppm; adjusted to either pH 8.5 or unadjusted natural pH) for either 10 s or 60 min to replicate treatments for chicken parts or whole carcasses, respectively. Treated chicken wings were rinsed in buffered peptone water (100 mL) containing sodium thiosulfate (0.1 %), serially diluted in peptone water supplemented with 200 ppm of nalidixic acid, rifampicin or kanamycin for enumeration of ST, SI, and SR respectively, and plated on APC Petrifilm. Immersion of chicken wings in 500 ppm PAA for 60 min resulted in greater microbial reductions (P ≤ 0.05) of ST, SI, SR of ca. Two log CFU/mL each, compared to 10 s treatment. Regardless of concentration and pH of PAA, increased exposure time (60 min vs. 10 s) resulted in greater reductions (P ≤ 0.05) of ST, SI, SR. ST was slightly more resistant to PAA solutions than S. Infantis and S. Reading (P ≤ 0.05) for all experimental conditions (PAA conc, pH, and exposure times). Faster decomposition of PAA (100 and 500 ppm) was observed at pH 8.5 compared to unadjusted, natural pH (P ≤ 0.05). Product color (lightness, L*) was not affected regardless of the PAA concentration, exposure time or the pH.

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.

Mitigating the attachment of Salmonella Infantis on isolated poultry skin with cetylpyridinium chloride

To provide the poultry industry with effective mitigation strategies, the effects of cetylpyridinium chloride (CPC) on the reduction of Salmonella Infantis, hilA expression, and chicken skin microbiota were evaluated. Chicken breast skins (4×4 cm; N = 100, n = 10, k = 5) were inoculated with Salmonella (Typhimurium or Infantis) at 4°C (30min) to obtain 108 CFU/g attachment. Skins were shaken (30s), with remaining bacteria being considered firmly attached. Treatments were applied as 30s dips in 50 mL: no inocula-no-treatment control (NINTC), no treatment control (NTC), tap water (TW), TW+600 ppm PAA (PAA), or TW+0.5% CPC (CPC). Excess fluid was shaken off (30s). Samples were homogenized in nBPW (1 min). Samples were discarded. Salmonella was enumerated and Log10 transformed. Reverse transcriptase-qPCR (rt-qPCR) was performed targeting hilA gene and normalized using the 2-ΔΔCt method. Data were analyzed using one-way ANOVA in RStudio with means separated by Tukey's HSD (P≤0.05). Genomic DNA of rinsates was extracted, 16S rRNA gene (V4) was sequenced (MiSeq), and data analyzed in QIIME2 (P≤0.05 and Q≤0.05). CPC and PAA affected Salmonella levels differently with CPC being effective against S. Infantis compared to TW (P<0.05). Treatment with CPC on S. Infantis-infected skin altered the hilA expression compared to TW (P<0.05). When inoculated with S. Typhimurium, there was no difference between the microbiota diversity of skins treated with PAA and CPC; however, when inoculated with S. Infantis, there was a difference in the Shannon's Entropy and Jaccard Dissimilarity between the two treatments (P<0.05). Using ANCOM at the genus level, Brochothrix was significant (W = 118) among skin inoculated with S. Typhimurium. Among S. Infantis inoculated, Yersiniaceae, Enterobacterales, Lachnospiraceae CHKCI001, Clostridia vadinBB60 group, Leuconostoc, Campylobacter, and bacteria were significant (408). CPC and PAA-treated skins had lowest relative abundance of the genera. In conclusion, CPC mitigated Salmonella Infantis, altered hilA expression, and influenced the chicken skin microbiota.

Comparison of peroxyacetic acid and acidified sodium chlorite at reducing natural microbial contamination on chicken meat pieces

The spin-chill process at poultry processing plants involves the immersion of chicken carcasses in cold water (<5°C) often containing sodium hypochlorite which significantly contributes to the reduction of bacterial loads. Cutting carcasses into pieces, however, has been linked with increases in Campylobacter and Salmonella counts. Here, the efficacy of PAA and ASC on reducing bacteria on skin-on, bone-in thigh cuts was investigated. Three concentrations of ASC (60, 112, and 225 ppm) and PAA (50, 75, 100 ppm) were used. Thighs were dipped into sanitizer and tested for total viable bacterial counts, Campylobacter load, and prevalence of Salmonella. The efficacy of PAA and ASC was also compared with chlorine (8 ppm). All sanitizers exhibited a greater log reduction compared with water. PAA at both 75 and 100 ppm resulted in significantly higher log reductions compared with the water only. PAA at 100 ppm and 225 ppm ASC were the most effective at reducing Campylobacter. All wash treatments reduced the proportion of Salmonella positive samples, but the greatest reduction was observed for 225 ppm ASC. Both concentrations of ASC resulted in a greater reduction in total viable counts compared with chlorine.

Peracetic acid application as an antimicrobial and its residual (HEDP): a holistic approach on the technological characteristics of chicken meat

The most significant occurrence of food-borne diseases is due to Campylobacter and Salmonella contamination from chicken meat, and for this reason, strict regulations about strategies to improve the control of food pathogens are imposed by food safety authorities. Despite the efforts of poultry industry since the beginning of risk analysis and critical control point to reduce the burden of food-borne illness, technological barriers along the way are increasingly necessary to ensure safe food. The aim of this review was to carry out a scientific approach to the influence of peracetic acid (PAA) as an antimicrobial and its toxicological safety, in particular the stabilizer used in the formulation of PAA, 1-hydroxyethylidene 1,1-diphosphonic acid (HEDP), suggesting the possibility of researching the residual HEDP in meat, which would allow the approval of the PAA by the health authorities of several countries that still restrict it. This review also aims to ascertain the effectiveness of PAA, in different cuts and carcasses, by different application methods, comparing the effectiveness of this antimicrobial with other antimicrobials, and its exclusive or combined use, for the decontamination of poultry carcasses and raw parts. The literature results support the popularity of PAA as an effective intervention against pathogenic bacteria during poultry processing.

Practical Preventive Considerations for Reducing the Public Health Burden of Poultry-Related Salmonellosis

With poultry products as one of the leading reservoirs for the pathogen, in a typical year in the United States, it is estimated that over one million individuals contract non-typhoidal Salmonella infections. Foodborne outbreaks associated with Salmonella infections in poultry, thus, continue to remain a significant risk to public health. Moreover, the further emergence of antimicrobial resistance among various serovars of Salmonella is an additional public health concern. Feeding-based strategies (such as use of prebiotics, probiotics, and/or phytobiotics as well as essential oils), non-feeding-based strategies (such as use of bacteriophages, vaccinations, and in ovo strategies), omics tools and surveillance for identifying antibiotic-resistance genes, post-harvest application of antimicrobials, and biosecurity measures at poultry facilities are practical interventions that could reduce the public health burden of salmonellosis and antibiotic resistance associated with poultry products. With the escalating consumption of poultry products around the globe, the fate, prevalence, and transmission of Salmonella in agricultural settings and various poultry-processing facilities are major public health challenges demanding integrated control measures throughout the food chain. Implementation of practical preventive measures discussed in the current study could appreciably reduce the public health burden of foodborne salmonellosis associated with poultry products.

Mild heat treatment achieved better inactivation of Salmonella and preservation of almond quality than ultraviolet light and chemical sanitizers

This study was conducted to compare the effects of ultraviolet light (UV), chemical sanitizers, and heat treatments on Salmonella inactivation and preservation of almond quality. Whole, skinless, and sliced almonds, representing different shape and surface topography, were inoculated with a Salmonella cocktail consisting of S. Montevideo, S. Newport, S. Typhimurium, S. Heidelberg, and S. Enteritidis. Inoculated almonds (50 g) were treated by UV (30 mW/cm², 30 or 60 min), 75 °C heat (up to 150 min), and chemical sanitizers (3 % hydrogen peroxide (H₂O₂) and 1 % cetylpyridinium chloride (CPC), 30 or 60 min) alone or in combinations. Uninoculated almonds were similarly treated for analyzing color, visual appearance, and weight changes. In general, UV treatment alone was ineffective in inactivating Salmonella; the 30- and 60-min UV treatments reduced Salmonella by 1.3 (± 0.1) and 1.7 (± 0.1), 2.7 (± 0.2) and 3.3 (± 0.1), and 1.3 (± 0.1) and 1.7 (± 0.1) log CFU/g on whole, skinless, and sliced almonds, respectively. Prior wetting of almonds with water and chemical solutions in a few cases significantly (P < 0.05) increased the UV inactivation of Salmonella. The most pronounced Salmonella killing effect achieved by the combined treatments were: 1-min H₂O₂ dipping followed by 60-min UV treatment for whole (3.0 logs) and skinless almonds (3.8 logs) and 1-min CPC dipping followed by 60-min UV treatment for sliced almonds (3.0 logs). However, none of those achieved >4 log reductions of Salmonella as required by FDA. The 30-min UV treatment produced discolored but overall acceptable almonds, whereas the 60-min UV treatment led to deteriorated almonds including a dark color, oil extraction, and shrunk kernel size. Prior wetting reduced the sample weight loss but caused local burning and kernel cracking. A sequential approach of a 60-min 75 °C heat treatment and two 30-min wet UV treatments successfully reduced Salmonella by >4 logs, but more severe kernel cracking occurred. In contrast, a single heat treatment of vacuum packaged whole almonds at 75 °C for 150 min was capable of achieving >5 log reductions of Salmonella while preserving almond color and visual qualities and minimizing weight loss. These results clearly demonstrated that the heat treatment was a much better processing technology than UV and sanitizers for raw almond pasteurization.

Efficacy of Antimicrobial Spray Treatments in Reducing Salmonella enterica Populations on Chilled Pork

Studies reporting on alternative antimicrobial interventions for pathogen control on chilled pork carcasses and cuts are limited. In this study, the antimicrobial effects of various spray treatments against Salmonella enterica inoculated on skin-on pork samples were evaluated. Chilled pork jowls were portioned (10 by 5 by 1 cm) and inoculated, on the skin side, with a mixture of six S. enterica serotype strains to target levels of 6 to 7 log CFU/cm² (high inoculation level) or 3 to 4 log CFU/cm² (low inoculation level). Samples were then left nontreated (control) or were treated (10 s) using a laboratory-scale spray cabinet with water, formic acid (1.5%), a proprietary blend of sulfuric acid and sodium sulfate (SSS, pH 1.2), peroxyacetic acid (PAA, 400 ppm), or PAA (400 ppm) that was pH-adjusted (acidified) with acetic acid (1.5%), formic acid (1.5%), or SSS (pH 1.2). Samples (n = 6) were analyzed for Salmonella populations after treatment application (0 h) and after 24 h of refrigerated (4°C) storage. Irrespective of inoculation level, all spray treatments effectively reduced (P < 0.05) Salmonella levels immediately following their application. Overall, pathogen reductions for the chemical treatments, compared to the respective high and low inoculation level nontreated controls, ranged from 1.2 to 1.9 log CFU/cm² (high inoculation level) and 1.0 to 1.7 log CFU/cm² (low inoculation level). Acidification of PAA with acetic acid, formic acid, or SSS did not (P ≥ 0.05) enhance the initial bactericidal effects of the nonacidified PAA treatment. Salmonella populations recovered from all treated samples following 24 h of storage were, in general, similar (P ≥ 0.05) or up to 0.6 log CFU/cm² lower (P < 0.05) than those recovered from samples analyzed immediately after treatment application. The results of the study may be used by processing establishments to help identify effective decontamination interventions for reducing Salmonella contamination on pork.

An Evaluation of Sporicidal Treatments against Blown Pack Spoilage Associated Clostridium estertheticum and Clostridium gasigenes Spores

Blown pack spoilage (BPS) occurs when meat is cross-contaminated with Clostridium estertheticum or Clostridium gasigenes spores, often from the meat processing environment. This study tested the efficacy of four sporicidal disinfectants commonly used in beef processing plants against C. estertheticum and C. gasigenes spores in a suspension test. D-values were obtained under model ‘clean’ (sterile distilled water, SDW) and ‘dirty’ (3 g/L bovine serum albumin, BSA) conditions. Mean concentration (log10 CFU/mL) were calculated from direct counts. The levels of dipicolinic acid (DPA), indicating damage to the core of these spores, was also monitored using a terbium (Tb)-DPA assay for treatment 1 (peracetic acid as the active ingredient) in SDW and BSA. In SDW sporicidal treatment 3 (containing peroxymonosulphate) was the most effective against C. estertheticum spores but under ‘dirty’ (BSA) conditions sporicidal treatments 1 and 2 were more effective. A similar pattern was obtained with C. gasigenes with treatment 3 being the most effective in SDW but treatment 2 (sodium hypochlorite as the active ingredient) being more effective in BSA. The lower DPA concentrations obtained in SDW versus BSA demonstrated the protective effect of organic matter. It was concluded that meat processors should use a 5% formulation containing sodium hypochlorite, sodium hydroxide and alkylamine oxide to eliminate BPS Clostridial spores in the abattoir.

Effects of Dietary Organic and Inorganic Sulfur on Laying Performance, Egg Quality, Ileal Morphology, and Antioxidant Capacity in Laying Hens

Simple Summary

Oxidative stress caused by environmental and nutritional factors could be detrimental to poultry production. Dietary natural antioxidants could therefore be beneficial in limiting the deleterious effects of oxidative stress in chickens. Methyl sulfonyl methane is a non-toxic natural organosulfur compound with the chemical formula (CH₃)₂SO₂ and is known as methyl sulfone or dimethyl sulfone. Inorganic sulfate (e.g., sodium sulfate) is involved in the metabolism of many tissues and systems, as well as in important detoxication mechanisms. Dietary sulfur in either organic or inorganic forms exhibits beneficial antioxidant properties in various animals in vivo and in vitro. Therefore, our studies have been conducted to evaluate the role of organic and inorganic sulfur in laying hens.

Abstract

The present study was conducted to investigate the comparative effects of organic and inorganic forms of sulfur, methyl sulfonyl methane (MSM) and sodium sulfate (SS), on laying performance, egg quality, ileal morphology, ileal volatile fatty acids, and antioxidant and stress markers in various biological samples in aged laying hens. A total of 144, 73-week-old Lohman Brown-Lite laying hens were randomly assigned to one of three experimental diets: basal diet (CONT), CONT + 0.2% MSM (MSM), and CONT + 0.3% SS (SS). The trial lasted for 12 weeks. MSM and SS diets contained 0.07% of sulfur, either organic or inorganic. Dietary MSM did not affect egg production or feed conversion ratio at 12 weeks compared with the CONT group. Dietary sulfur did not affect egg quality except for the Haugh unit at 4 weeks, which was lowered (p < 0.05) in the SS group. Compared with the CONT group, a higher (p < 0.05) villus height to crypt depth ratio was observed in the SS group. Dietary sulfur did not affect the percentages of short-chain fatty acids in the ileum. Total antioxidant capacity of the liver increased (p < 0.05) in laying hens fed MSM- and SS-added diets compared with the CONT group. The MSM and SS groups were found to have lowered (p < 0.05) malondialdehyde (MDA) concentration in serum samples compared with CONT. Finally, dietary MSM had the lowest (p < 0.05) MDA concentrations in yolk samples. Taken together, our study showed that dietary organic and inorganic sulfur have positive effects on ileal morphology and antioxidant capacity in laying hens. However, SS-mediated inhibition in laying performance needs to be clarified.

Application of Peroxyacetic Acid for Decontamination of Raw Poultry Products and Comparison to Other Commonly Used Chemical Antimicrobial Interventions: A Review

ABSTRACT

Poultry remains one of the top food commodities responsible for foodborne illness in the United States, despite poultry industry efforts since the inception of hazard analysis and critical control point to reduce the burden of foodborne illness implicating poultry products. The appropriate use of antimicrobial compounds during processing of raw poultry can help minimize this risk. Currently, peroxyacetic acid (PAA) is the most popular antimicrobial in the poultry industry, displacing chlorine compounds and others. The aim of this review was to compare the effectiveness of PAA to that of other antimicrobials for the decontamination of raw poultry carcasses and parts. Twenty-six articles were found that compared PAA with over 20 different antimicrobials, applied as spray or immersion treatments for different exposure times and at different concentrations. The most common comparisons were to chlorine compounds (17 articles), to lactic acid compounds (five articles), and to cetylpyridinium chloride (six articles). Studies measured effectiveness by reductions in native flora or inoculated bacteria, usually Salmonella or Campylobacter. PAA was found to be more effective than chlorine under most conditions studied. Effectiveness of PAA was higher than or comparable to that of lactic acid compounds and cetylpyridinium chloride depending on product and treatment conditions. Overall, the results of primary literature studies support the popularity of PAA as an effective intervention against pathogenic bacteria during poultry processing.

HIGHLIGHTS

Reduction of Salmonella Infantis on skin-on, bone-in chicken thighs by cetylpyridinium chloride application and the impact on the skin microbiota

Salmonella Infantis has been the etiological agent of numerous foodborne outbreaks of nontyphoidal Salmonella. Consequently, there is an emergent need to mitigate Salmonella Infantis among poultry. Thus, this study evaluated the efficacy of cetylpyridinium chloride (CPC) versus peroxyacetic acid (PAA), on bone-in, skin-on chicken thighs for the reduction of Salmonella and changes in the microbiota. Exactly 100 skin-on, bone-in chicken thighs (2 trials, 0 and 24 h, k = 5, n = 5, N = 50) were inoculated with 10⁸ CFU/mL of a nalidixic acid resistant strain of S. Infantis for an attachment of 10⁶ CFU/g. Thighs were treated with 20 s part dips (350 mL): a no inoculum, no treatment control (NINTC); no treatment control (NTC); tap water (TW); TW+CPC; TW+PAA. Following treatment, thighs were rinsed in 150 mL of nBPW, and rinsates were collected. Rinsates were spot plated for Salmonella and aerobic bacteria (APC). Log₁₀ transformed counts were analyzed using a mixed-effects model (random effect = trial) with means separated using Tukey's HSD (P ≤ 0.05). The genomic DNA of rinsates was extracted, and the 16S rDNA was sequenced on an Illumina MiSeq. Microbiota data were analyzed using QIIME2, with data considered significant at P ≤ 0.05 (main effects) and Q≤0.05 (pairwise differences). Treatment × time interactions were observed for both Salmonella and APC (P < 0.05). The treatment of thighs with PAA and CPC reduced Salmonella and APC in respect to the controls. Numerically, thighs treated with CPC had less Salmonella (4.29 log₁₀CFU/g) and less APC (4.56 log₁₀CFU/g) at 24 h than all other treatments (P > 0.05). Differences in diversity metrics were not consistently observed between treatments; however, in trial 2, the NTC treated thighs were different than those treated with CPC (P < 0.05; Q < 0.05). In both trials, ANCOM, the analysis of microbiome compositional profiles, revealed shifts at both the phylum and order levels with thighs being different in the relative abundances of Proteobacteria (P < 0.05). In conclusion, treatment of skin-on poultry parts with CPC may reduce the risk of foodborne outbreaks caused by Salmonella Infantis.

Evaluation of Immersion and Spray Applications of Antimicrobial Treatments for Reduction of Campylobacter jejuni on Chicken Wings

The decontamination efficacy of antimicrobial treatments against Campylobacter jejuni on chicken wings was evaluated. Chicken wings surface-inoculated with C. jejuni (3.9 log colony-forming units [CFU]/mL) were left untreated (control) or were treated by immersion (5 s) or in a spray cabinet (4 s) with water, a sulfuric acid and sodium sulfate blend (SSS; pH 1.2), formic acid (1.5%), peroxyacetic acid (PAA; 550 ppm), or PAA (550 ppm) that was pH-adjusted (acidified) with SSS (pH 1.2) or formic acid (1.5%). All evaluated immersion and spray chemical treatments effectively (p < 0.05) lowered C. jejuni populations on chicken wings. Spray application of chemical treatments resulted in immediate pathogen reductions ranging from 0.5 to 1.2 log CFU/mL, whereas their application by immersion lowered initial pathogen levels by 1.7 to 2.2 log CFU/mL. The PAA and acidified PAA treatments were equally (p ≥ 0.05) effective at reducing initial C. jejuni populations, however, following a 24 h refrigerated (4 °C) storage period, wings treated with acidified PAA had lower (p < 0.05) pathogen levels than samples that had been treated with PAA that was not acidified. Findings of this study should be useful to the poultry industry in its efforts to control Campylobacter contamination on chicken parts.

Impact of pH on efficacy of peroxy acetic acid against Salmonella, Campylobacter, and Escherichia coli on chicken wings

Peroxy acetic acid (PAA) is widely used as an antimicrobial in poultry processing, specifically in the chiller. While the natural pH of PAA at the concentrations used is between 4.5 and 6.0, poultry processors adjust the pH to ≥8.0 to maintain product yield. The objective of this study was to evaluate 1) efficacy of PAA at different concentrations, pH, and contact times against Salmonella, Campylobacter, and Escherichia coli and 2) use of E. coli as a surrogate for Salmonella and Campylobacter to conduct validations studies for poultry processing. Fresh chicken wings (0.45 Kg) were inoculated with a cocktail of nalidixic acid-resistant Salmonella Typhimurium, rifampicin-resistant E. coli (5-strain cocktail), and gentamicin-resistant Campylobacter coli. Inoculated chicken wings were immersed in PAA solutions of 50, 250, and 500 ppm adjusted to pH 8.2 and 10.0 as well as nonadjusted PAA solutions for 10 s and 60 min. Treated chicken wings were rinsed in chilled buffered peptone water, serially diluted, and plated on Petrifilm APC for enumerating Salmonella and E. coli populations and spread plated on Campy Cefex Agar containing gentamicin (200 ppm) to enumerate Campylobacter. Immersion of chicken wings in 500 ppm of PAA (non-pH-adjusted) for 60 min resulted in greater microbial reductions (P ≤ 0.05) of Salmonella, Campylobacter, and E. coli populations of 2.56, 1.90, and 2.53 log CFU/mL, respectively. Higher concentrations and longer exposure times resulted in greater reductions (P ≤ 0.05) of Salmonella, E. coli, and Campylobacter populations, and increasing pH of PAA solution did not affect (P > 0.05) its efficacy. A high correlation (r = 0.93) was observed between E. coli (surrogate) and Salmonella populations suggesting that E. coli can be used as a surrogate for Salmonella for conducting validation studies for antimicrobial efficacy testing in poultry processing.

Application of Amplon in combination with peroxyacetic acid for the reduction of nalidixic acid-resistant Salmonella Typhimurium and Salmonella Reading on skin-on, bone-in tom turkey drumsticks

Peroxyacetic acid (PAA) has become an important component of pathogen reduction in poultry processing, but there are potential concerns for continued exposure. The objective was to evaluate the effects of PAA and Amplon (AMP) used alone or in the combination. Bone-in tom turkey drumsticks (N = 100, n = 10, k = 5, 0 and 24 h) per study were obtained and inoculated with either nalidixic acid–resistant Salmonella Typhimurium or Salmonella Reading (64 μg/mL). The inocula were allowed to adhere to the drums at 4°C for 60 min for a final attachment of 10⁸ and 10⁷ cfu/g per S. Typhimurium and S. Reading, respectively. Drumsticks were treated with a no-treatment control; tap water, pH 8.5 (TW); TW+500 ppm PAA, pH 3.5 (PAA); TW+500 ppm AMP, pH 1.3 (AMP); TW + PAA + AMP (PAA + AMP). Treatments were applied as short duration dips (30 s) and allowed to drip for 2 min. After treatment, drums were stored at 4°C until microbial analyses at 0 and 24 h. Drums were rinsed in neutralizing buffered peptone water and spot plated for total aerobes and Salmonella. Bacterial counts were log₁₀ transformed and analyzed using n-way ANOVA. All treatments reduced S. Reading on turkey legs at both 0 and 24 h (P < 0.0001; P < 0.0001). At 24 h, drums treated with PAA + AMP (3.92 log₁₀ cfu/g) had less S. Reading than no-treatment control, TW, and AMP. Treatment by time interactions were observed for total aerobes among drums in both studies (P < 0.0001, P < 0.0001) and Salmonella among drums inoculated with S. Typhimurium (P < 0.0001). During the S. Reading and S. Typhimurium study, all treatments reduced Salmonella and total aerobes on drums. During the S. Typhimurium study, drums treated with PAA + AMP had the lowest numerical load of S. Typhimurium and total aerobes. The combination of AMP + PAA may exhibit a synergistic effect in reducing Salmonella on turkey drums, thus increasing the safety of turkey products for consumers.

Antimicrobial interventions to reduce Salmonella and Campylobacter populations and improve shelf life of quail carcasses

Quail (Coturnix japonica) is processed and marketed as fresh meat, with limited shelf life. The objective of this study was to evaluate the efficacy of antimicrobial interventions during slaughter on reducing Salmonella and Campylobacter contamination and to determine the microbiological shelf life of quail during refrigerated (4°C) storage. Three antimicrobials, peracetic acid (400 ppm; PAA), Citrilow (pH 1.2), and Cecure (cetylpyridinium chloride [CPC], 450 ppm), along with a water and no-treatment control were evaluated. Quail carcasses (n = 75) were inoculated with a cocktail of nalidixic acid–resistant Salmonella Typhimurium and gentamicin-resistant Campylobacter coli. After 30 min of attachment time, quail carcasses were submerged in each antimicrobial solution for 20 s with air agitation. Noninoculated quail carcasses (n = 25) were similarly treated, packaged, and stored under refrigeration (4°C). Aerobic plate counts (APC), psychrotroph counts (PC), Enterobacteriaceae counts (ENT), total coliform counts (TCC), and Escherichia coli counts on quail carcasses were determined on 1, 4, 7, and 10 d. Salmonella and Campylobacter populations were determined by plating on Petrifilm APC supplemented with 200-ppm nalidixic acid and Campy Cefex agar supplemented with 200-ppm gentamycin, respectively. No significant reductions in (P > 0.01 log cfu/mL) in APC, PC, ENT, TCC, and E. coli counts were observed on carcasses submerged in water. However, treatments with PAA, Citrilow, and CPC significantly reduced (P ≤ 0.05) Salmonella and Campylobacter coli contamination. Citrilow showed greater (P ≤ 0.05) reduction in Salmonella and Campylobacter population (1.90 and 3.82 log cfu/mL reduction, respectively) to PAA and CPC. Greater (P ≤ 0.05) reductions in APC, PC, ENT, TCC, and E. coli counts (2.22, 1.26, 1.47, 1.52, and 1.59 log cfu/mL, respectively) were obtained with the application of CPC. Application of antimicrobial interventions resulted in a reduction in Campylobacter and Salmonella, APC, PC, and ENT populations after treatments (day 0) and throughout the storage period (day 10). Use of antimicrobial interventions after slaughter can improve the microbiological safety and shelf life of quail.

A Review of Salmonella and Campylobacter in Broiler Meat: Emerging Challenges and Food Safety Measures

Poultry is one of the largest sources of animal-based protein in the United States. Poultry processing has grown from a small local network of plants to nearly 500 plants nationwide. Two of the most persistent bacteria in poultry processing are Salmonella and Campylobacter. It was not until the introduction of Hazard Analysis and Critical Control Point systems in 1996 that major efforts to reduce bacterial contamination were developed. Traditionally, chlorine has been the industry standard for decontaminating chicken meat. However, antimicrobials such as peracetic acid, cetylpyridinium chloride, and acidified sodium chlorite have replaced chlorine as primary antimicrobials. Despite current interventions, the emergence of stress-tolerant and biofilm-forming Salmonella and Campylobacter is of primary concern. In an effort to offset growing tolerance from microbes, novel techniques such as cold plasma treatment, electrostatic spraying, and bacteriophage-based applications have been investigated as alternatives to conventional treatments, while new chemical antimicrobials such as Amplon and sodium ferrate are investigated as well. This review provides an overview of poultry processing in the United States, major microbes in poultry processing, current interventions, emerging issues, and emerging technologies in antimicrobial treatments.

Efficacy of peroxy acetic acid in reducing Salmonella and Campylobacter spp. populations on chicken breast fillets

Poultry processors use antimicrobials to reduce the risk of pathogens on poultry and poultry products. The efficacy of selective and nonselective plating media to enumerate injured Salmonella (selective media-brilliant green sulfa agar and Petrifilm Enterobacteriaceae Plate Count; nonselective media-tryptic soy agar and Petrifilm Aerobic Plate Count) and Campylobacter (selective medium-Campy cefex agar and nonselective medium-Brucella agar) populations and the efficacy of peroxy acetic acid (PAA) to reduce Salmonella and Campylobacter populations on chicken breast fillets were evaluated. All plating media for Salmonella and Campylobacter contained nalidixic acid (200 ppm) or gentamycin (200 ppm), respectively. Breast fillets were sprayed or immersed in PAA (500 ppm) for 10 min for evaluation of the plating media. Breast fillets inoculated with a mixed Salmonella and Campylobacter cocktail were sprayed (5 or 10 s) or immersed (4-30 s) in PAA (100, 400, 500, or 1,000 ppm) for evaluation of PAA efficacy. Salmonella populations were higher (P ≤ 0.05) when plated on nonselective media compared with the selective media for the non-PAA treated fillets, although the differences in populations were low (<0.32 log CFU/mL). For both the microorganisms, populations on PAA treated (immersion or spray) fillets were similar when enumerated on nonselective or selective media within each treatment (PAA immersion or spray). Both immersion and spray applications reduced (P ≤ 0.05) the Salmonella and Campylobacter populations compared with the control. Increasing the PAA concentration to 250, 500, and 1,000 ppm resulted in greater reductions (P ≤ 0.05) in Salmonella and Campylobacter populations. Immersion of the inoculated breast fillets in 1,000 ppm PAA solution for 30 s resulted in Salmonella and Campylobacter population reductions of 1.92 and 1.87 log CFU/mL, respectively. Method of antimicrobial application (immersion and spray) did not affect the reductions in Salmonella and Campylobacter populations. Either immersion or spray application can be used to improve microbial safety of chicken breast fillets in a poultry processing plant.

Principles and applications of non-thermal technologies and alternative chemical compounds in meat and fish

Conventional methods of food preservation have demonstrated several disadvantages and limitations in the efficiency of the microbial load reduction and maintain food quality. Hence, non-thermal preservation technologies (NTPT) and alternative chemical compounds (ACC) have been considered a high promissory replacer to decontamination, increasing the shelf life and promoting low levels of physicochemical, nutritional and sensorial alterations of meat and fish products. The combination of these methods can be a potential alternative to the food industry. This review deals with the most critical aspects of the mechanisms of action under microbial, physicochemical, nutritional and sensorial parameters and the efficiency of the different NTPT (ultrasound, high pressure processing, gamma irradiation and UV-C radiation) and ACC (peracetic acid, bacteriocins, nanoparticles and essential oils) applied in meat and fish products. The NTPT and ACC present a high capacity of microorganisms inactivation, ensuring low alterations level in the matrix and high reduction of environmental impact. However, the application conditions of the different methods as exposition time, energy intensity and concentration thresholds of chemical compounds need to be specifically established and continuously improved for each matrix type to reduce to the maximum the physicochemical, nutritional and sensorial changes. In addition, the combination of the methods (hurdle concept) may be an alternative to enhance the matrix decontamination. In this way, undesirable changes in meat and fish products can be further reduced without a decrease in the efficiency of the decontamination.

Transcriptome Analysis of Salmonella Heidelberg after Exposure to Cetylpyridinium Chloride, Acidified Calcium Hypochlorite, and Peroxyacetic Acid

The application of RNA sequencing in commercial poultry could facilitate a novel approach toward food safety with respect to identifying conditions in food production that mitigate transcription of genes associated with virulence and survivability. In this study, we evaluated the effects of disinfectant exposure on the transcriptomes of two field isolates of Salmonella Heidelberg (SH) isolated from a commercial broiler processing plant in 1992 and 2014. The isolates were each exposed separately to the following disinfectants commonly used in poultry processing: cetylpyridinium chloride (CPC), acidified calcium hypochlorite (aCH), and peroxyacetic acid (PAA). Exposure times were 8 s with CPC to simulate a poultry processing dipping station or 90 min with aCH and PAA to simulate the chiller tank in a poultry processing plant at 4°C. Based on comparison with a publicly available annotated SH reference genome with 5,088 genes, 90 genes were identified as associated with virulence, pathogenicity, and resistance (VPR). Of these 90 VPR genes, 9 (10.0%), 28 (31.1%), and 1 (1.1%) gene were upregulated in SH 2014 and 21 (23.3%), 26 (28.9%), and 2 (2.2%) genes were upregulated in SH 2014 challenged with CPC, aCH, and PAA, respectively. This information and previously reported MICs for the three disinfectants with both SH isolates allow researchers to make more accurate recommendations regarding control methods of SH and public health considerations related to SH in food production facilities where SH has been isolated. For example, the MICs revealed that aCH is ineffective for SH inhibition at regulatory levels allowed for poultry processing and that aCH was ineffective for inhibiting SH growth and caused an upregulation of VPR genes.

Salmonella Contamination in Broiler Synovial Fluid: Are We Missing a Potential Reservoir?

The objective of this study was to assess the presence and characteristics of Salmonella enterica found in the synovial fluid of broiler carcasses. The synovial fluid of three individual joints from 500 broiler carcasses was individually sampled from five broiler processing facilities located in the Southeast and West regions of the United States (1,500 total samples). The external surface of broiler carcass was decontaminated before sampling of the shoulder, coxofemoral, and tibiofemoral joints. Individual samples were enriched, composited, and subjected to rapid PCR-based detection of Salmonella. Individual samples from any positive composites were also enriched before determination of Salmonella presence in the same manner. Positive individual samples were subjected to secondary enrichment before plating onto selective agar for isolation of Salmonella. Salmonella isolates were serotyped before determination of antimicrobial susceptibility. Overall, 1.00% (5 of 500 broiler carcasses) of composite samples and 0.47% (7 of 1,500 samples) of individual samples were positive for Salmonella. Five of the seven isolates were susceptible to all drugs tested and determined to be Salmonella Enteritidis. The remaining two isolates, identified as Salmonella Typhimurium, were resistant to streptomycin. To our knowledge, no previous assessments of Salmonella in the synovial fluid of broilers has been reported; however, results of the present study suggested that the synovial fluid may be a reservoir for Salmonella in broilers. Although the prevalence of Salmonella is low, this information provides valuable insight into potential poultry contamination pathways and warrants further exploration.

Efficacy of a Blend of Sulfuric Acid and Sodium Sulfate against Shiga Toxin-Producing Escherichia coli, Salmonella, and Nonpathogenic Escherichia coli Biotype I on Inoculated Prerigor Beef Surface Tissue

A study was conducted to investigate the efficacy of a sulfuric acid-sodium sulfate blend (SSS) against Escherichia coli O157:H7, non-O157 Shiga toxin-producing E. coli (STEC), Salmonella, and nonpathogenic E. coli biotype I on prerigor beef surface tissue. The suitability of using the nonpathogenic E. coli as a surrogate for in-plant validation studies was also determined by comparing the data obtained for the nonpathogenic inoculum with those for the pathogenic inocula. Prerigor beef tissue samples (10 by 10 cm) were inoculated (ca. 6 log CFU/cm²) on the adipose side in a laboratory-scale spray cabinet with multistrain mixtures of E. coli O157:H7 (5 strains), non-O157 STEC (12 strains), Salmonella (6 strains), or E. coli biotype I (5 strains). Treatment parameters evaluated were two SSS pH values (1.5 and 1.0) and two spray application pressures (13 and 22 lb/in²). Untreated inoculated beef tissue samples served as controls for initial bacterial populations. Overall, the SSS treatments lowered inoculated (6.1 to 6.4 log CFU/cm²) bacterial populations by 0.6 to 1.5 log CFU/cm² (P < 0.05), depending on inoculum type and recovery medium. There were no main effects (P ≥ 0.05) of solution pH or spray application pressure when SSS was applied to samples inoculated with any of the tested E. coli inocula; however, solution pH did have a significant effect (P < 0.05) when SSS was applied to samples inoculated with Salmonella. Results indicated that the response of the nonpathogenic E. coli inoculum to the SSS treatments was similar (P ≥ 0.05) to that of the pathogenic inocula tested, making the E. coli biotype I strains viable surrogate organisms for in-plant validation of SSS efficacy on beef. The application of SSS at the tested parameters to prerigor beef surface tissue may be an effective intervention for controlling pathogens in a commercial beef harvest process.

Impact of Built-up-Litter and Commercial Antimicrobials on Salmonella and Campylobacter Contamination of Broiler Carcasses Processed at a Pilot Mobile Poultry-Processing Unit

The small-scale mobile poultry-processing unit (MPPU) produced raw poultry products are of particular food safety concern due to exemption of USDA poultry products inspection act. Limited studies reported the microbial quality and safety of MPPU-processed poultry carcasses. This study evaluated the Salmonella and Campylobacter prevalence in broiler ceca and on MPPU-processed carcasses and efficacy of commercial antimicrobials against Campylobacter jejuni on broilers. In study I, straight-run Hubbard × Cobb broilers (147) were reared for 38 days on clean-shavings (CS, 75) or built-up-litter (BUL, 72) and processed at an MPPU. Aerobic plate counts (APCs), coliforms, Escherichia coli, and yeast/molds (Y/M) of carcasses were analyzed on petrifilms. Ceca and carcass samples underwent microbial analyses for Salmonella and Campylobacter spp. using the modified USDA method and confirmed by API-20e test (Salmonella), latex agglutination immunoassay (Campylobacter), and Gram staining (Campylobacter). Quantitative polymerase chain reaction (CadF gene) identified the prevalence of C. jejuni and Campylobacter coli in ceca and on carcasses. In study II, fresh chilled broiler carcasses were spot inoculated with C. jejuni (4.5 log₁₀ CFU/mL) and then undipped, or dipped into peroxyacetic acid (PAA) (1,000 ppm), lactic acid (5%), lactic and citric acid blend (2.5%), sodium hypochlorite (69 ppm), or a H₂O₂–PAA mix (SaniDate^® 5.0, 0.25%) for 30 s. Surviving C. jejuni was recovered onto Brucella agar. APCs, coliforms, and E. coli populations were similar (P > 0.05) on CS and BUL carcasses. Carcasses of broilers raised on BUL contained a greater (P < 0.05) Y/M population (2.2 log₁₀ CFU/mL) than those reared on CS (1.8 log₁₀ CFU/mL). Salmonella was not detected in any ceca samples, whereas 2.8% of the carcasses from BUL were present with Salmonella. Prevalence of Campylobacter spp., C. jejuni was lower (P < 0.05), and C. coli was similar (P > 0.05) in CS-treated ceca than BUL samples. Prevalence of Campylobacter spp., C. jejuni, and C. coli was not different (P > 0.05) on CS- and BUL-treated carcasses. All antimicrobials reduced C. jejuni by 1.2–2.0 log CFU/mL on carcasses compared with controls. Hence, raising broilers on CS and applying post-chilling antimicrobial treatment can reduce Salmonella and Campylobacter on MPPU-processed broiler carcasses.

Comparison of the Efficacy of a Sulfuric Acid-Sodium Sulfate Blend and Lactic Acid for the Reduction of Salmonella on Prerigor Beef Carcass Surface Tissue

A study was conducted to compare the efficacy of a commercially available sulfuric acid-sodium sulfate blend (SSS) and lactic acid (LA) in reducing inoculated Salmonella populations on beef. Sixty pieces of prerigor beef carcass surface brisket tissue, collected directly from the processing line of a commercial beef processing plant, were cut into two sections (10 by 10 cm each) and spot inoculated (6 to 7 log CFU/cm2) on the adipose side with a six-strain mixture of Salmonella. One section per piece of brisket tissue was left untreated (control), while the second section was spray treated (5 s, 15 lb/in2, and 33 mL/s flow rate) with unheated (21°C) or heated (52°C) solutions of SSS (pH 1.1) or LA (4%). Unheated and heated SSS lowered (P < 0.05) total bacterial counts from 6.3 to 4.6 and 4.3 log CFU/cm2, respectively. Likewise, unheated and heated LA reduced (P < 0.05) total bacterial counts from 6.3 to 4.7 and 4.4 log CFU/cm2, respectively. Initial counts of inoculated Salmonella populations (6.1 to 6.2 log CFU/cm2) were reduced (P < 0.05) to 4.2 and 3.9 log CFU/cm2 following treatment with unheated and heated SSS, respectively, and to 3.7 and 3.8 log CFU/cm2 after treatment with unheated and heated LA, respectively. Overall, the temperature of the chemical solutions had a small (0.3 log CFU/cm2), but significant (P < 0.05), effect on total bacterial counts but not (P > 0.05) on Salmonella counts. Regardless of solution temperature, Salmonella counts for LA-treated samples were 0.3 log CFU/cm2 lower (P < 0.05) than those of samples treated with SSS. These results indicate that both unheated and heated solutions of SSS and LA are effective interventions for reducing Salmonella contamination on prerigor beef carcass surface tissue.

Assessment of Chicken Carcass Microbiome Responses During Processing in the Presence of Commercial Antimicrobials Using a Next Generation Sequencing Approach

The purpose of this study was to 1) identify microbial compositional changes on chicken carcasses during processing, 2) determine the antimicrobial efficacy of peracetic acid (PAA) and Amplon (blend of sulfuric acid and sodium sulfate) at a poultry processing pilot plant scale, and 3) compare microbial communities between chicken carcass rinsates and recovered bacteria from media. Birds were collected from each processing step and rinsates were applied to estimate aerobic plate count (APC) and Campylobacter as well as Salmonella prevalence. Microbiome sequencing was utilized to identify microbial population changes over processing and antimicrobial treatments. Only the PAA treatment exhibited significant reduction of APC at the post chilling step while both Amplon and PAA yielded detectable Campylobacter reductions at all steps. Based on microbiome sequencing, Firmicutes were the predominant bacterial group at the phyla level with over 50% frequency in all steps while the relative abundance of Proteobacteria decreased as processing progressed. Overall microbiota between rinsate and APC plate microbial populations revealed generally similar patterns at the phyla level but they were different at the genus level. Both antimicrobials appeared to be effective on reducing problematic bacteria and microbiome can be utilized to identify optimal indicator microorganisms for enhancing product quality.