Modeling the influence of propionic acid concentration and pH on the kinetics of Salmonella Typhimurium

Salmonella Typhimurium is a foodborne pathogen often found in the poultry production chain. Antibiotics have been used to reduce S. Typhimurium contamination in poultry aviaries and improve chicken growth. However, antibiotics were banned in several countries. Alternatively, organic acids, such as propionic acid (PA), can control pathogens. This study determined the PA minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and mathematically modeled S. Typhimurium growth/inactivation kinetics under the influence of PA at different pH values (4.5, 5.5, and 6.5) which are within the pH range of the chicken gastrointestinal tract. The PA MIC against S. Typhimurium was pH-dependent, resulting in 5.0, 3.5 and 9.0 mM undissociated PA at pH 4.5, 5.5, and 6.5, respectively. The Baranyi and Roberts and the Weibull model fit growth and inactivation data well, respectively. Secondary models were proposed. The validated model predicted 3-log reduction of S. Typhimurium in 3 h at 68.2 mM of undissociated PA and pH 4.5. The models presented a good capacity to describe the kinetics of S. Typhimurium subjected to PA, representing a useful tool to predict PA antibacterial action depending on the pH.

Antimicrobial efficacy of a citric acid/hydrochloric acid blend, peroxyacetic acid, and sulfuric acid against Salmonella and background microbiota on chicken hearts and livers

This study aimed at evaluating the efficacy of a blend of citric acid and hydrochloric acid (CP), peroxyacetic acid (PAA), and sulfuric acid (SA) against Salmonella and mesophilic aerobic plate counts (APC) on chicken hearts and livers. Samples were inoculated with a five-serovar cocktail of Salmonella at ca. 4.8 log CFU/g and treated by immersion with a water control (90 s), CP (5% v/v, 30 s), PAA (0.05% v/v or 500 ppm, 90 s), or SA (2% v/v, 30 s), all at 4°C and with mechanical agitation. Samples were vacuum packed and stored for up to 3 days at 4°C. Three independent replications were performed for each product, treatment, and time combination. The average Salmonella reductions in chicken hearts after 3 days were 1.33 ± 0.25, 1.40 ± 0.04, and 1.32 ± 0.12 log CFU/g for PAA, SA, and CP, respectively. For chicken livers, the values were 1.10 ± 0.12, 1.09 ± 0.19, and 0.96 ± 0.27 for PAA, SA, and CP, respectively. All antimicrobials reduced Salmonella counts in both chicken hearts and livers by more than one log, in contrast to the water control. All treatments effectively minimized the growth of APC for up to 3 days of refrigerated storage, and no differences in objective color values (L, a, or b) were observed. The poultry industry may use these antimicrobials as components of a multifaceted approach to mitigate Salmonella in nonconventional chicken parts.

Bactericidal Effects and Quality Impact of Peroxyacetic Acid and Sodium Hypochlorite on Chicken Carcasses

There is an urgent need to develop efficient and environmentally friendly decontaminants for poultry products. In this study, we aimed to evaluate the practical application of peroxyacetic acid (PAA) as a replacement for sodium hypochlorite (SH) to sterilize fresh chicken carcasses, using microbial, color, and electronic-nose analyses. We evaluated the decontamination effects of different concentrations of PAA and SH on chicken carcasses. The bactericidal effects of PAA at pH 3, 7, and 9, and SH at pH 10, at concentrations ranging from 100 to 500 ppm on coliform bacteria, total bacteria, and Salmonella spp. were evaluated. PAA induced a similar bactericidal effect at lower concentrations than SH. Therefore, at the same concentration and treatment time, PAA showed better bactericidal effects than SH. Although treatment with PAA (pH 3) and SH (pH 10) resulted in considerable discoloration, the degree of discoloration decreased when the pH of PAA was increased to 7 and 9. Therefore, by increasing the pH of PAA, the discoloration effect on chicken carcasses can be reduced without altering the microbial-reduction effect. Electronic-nose analysis showed that the flavor of the chicken was almost unaffected by volatile components at a treatment time < 30 min. Therefore, this study experimentally identified the optimal PAA concentration for the decontamination of chicken carcasses. The study findings provide a theoretical basis for the replacement of traditional bactericides, such as SH, with PAA for the production of poultry products.

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.

Investigation of the Suitability of a Combination of Ethyl-Να-dodecanyl-L-arginat_HCl (LAE) and Starter Culture Bacteria for the Reduction of Bacteria from Fresh Meat of Different Animal Species

Meat can be contaminated with (pathogenic) microorganisms during slaughter, dissection and packaging. Therefore, preservation technologies are frequently used to reduce the risk of (fatal) human infections due to the consumption of meat. In this study, we first investigated, if the application of ethyl-Nα-dodecanyl-L-arginate hydrochloride (LAE) and the starter culture bacteria Staphylococcus carnosus and Lactobacillus sakei, either single or in combination, influences the bacteria number on pork, chicken meat and beef, inoculated with Brochothrix (Br.) thermosphacta (all meat species) or Salmonella (S.) Typhimurium (pork), Campylobacter (C.) jejuni (chicken) and Listeria (L.) monocytogenes (beef), before packaging under modified atmosphere and on days 7 and 14 of storage. To evaluate effects of the treatment on the appearance during storage, additionally, the physicochemical parameters color and myoglobin redox form percentages were analyzed. LAE regularly resulted in a significant reduction of the number of all bacteria species on day 1 of storage, whereas up to day 14 of storage, the preservation effect did not persist in nearly all samples, except in the beef with Br. thermosphacta. However, with the starter culture bacteria on day 1, only L. monocytogenes on beef was significantly reduced. Interestingly, on day 7 of storage, this reducing effect was also found with S. Typhimurium on pork. Br. thermosphacta, which was principally not influenced by the starter culture bacteria. The combinatory treatment mainly resulted in no additional effects, except for the S. Typhimurium and Br. thermosphacta results on pork on day 7 and the Br. thermosphacta results on beef on day 14. The physicochemical parameters were not influenced by the single and combinatory treatment. The results indicate that LAE was mainly responsible for the antimicrobial effects and that a combination with starter culture bacteria should be individually evaluated for the meat species.

Advances in enteropathogen control throughout the meat chicken production chain

Enteropathogens, namely Salmonella and Campylobacter, are a concern in global public health and have been attributed in numerous risk assessments to a poultry source. During the last decade, a large body of research addressing this problem has been published. The literature reviewed contains review articles on certain aspects of poultry production chain; however, in the past decade there has not been a review on the entire chain-farm to fork-of poultry production. For this review, a pool of 514 articles were selected for relevance via a systematic screening process (from >7500 original search articles). These studies identified a diversity of management and intervention strategies for the elimination or reduction of enteropathogens in poultry production. Many studies were laboratory or limited field trials with implementation in true commercial operations being problematic. Entities considering using commercial antienteropathogen products and interventions are advised to perform an internal validation and fit-for-purpose trial as Salmonella and Campylobacter serovars and biovars may have regional diversity. Future research should focus on nonchemical application within the processing plant and how a combination of synergisticinterventions through the production chain may contribute to reducing the overall carcass burden of enteropathogens, coupled with increased consumer education on safe handling and cooking of poultry.

Lauric arginate ethyl ester: An update on the antimicrobial potential and application in the food systems

Lauric arginate ethyl ester (LAE), a cationic surfactant with low toxicity, displays excellent antimicrobial activity against a broad range of microorganisms. LAE has been approved as generally recognized as safe (GRAS) for widespread application in certain foods at a maximum concentration of 200 ppm. In this context, extensive research has been carried out on the application of LAE in food preservation for improving the microbiological safety and quality characteristics of various food products. This study aims to present a general review of recent research progress on the antimicrobial efficacy of LAE and its application in the food industry. It covers the physicochemical properties, antimicrobial efficacy of LAE, and the underlying mechanism of its action. This review also summarizes the application of LAE in various foods products as well as its influence on the nutritional and sensory properties of such foods. Additionally, the main factors influencing the antimicrobial efficacy of LAE are reviewed in this work, and combination strategies are provided to enhance the antimicrobial potency of LAE. Finally, the concluding remarks and possible recommendations for the future research are also presented in this review. In summary, LAE has the great potential application in the food industry. Overall, the present review intends to improve the application of LAE in food preservation.

Inactivation methods for human coronavirus 229E on various food-contact surfaces and foods

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), the cause of the COVID-19 outbreaks, is transmitted by respiratory droplets and has become a life-threatening viral pandemic worldwide. The aim of this study was to evaluate the effects of different chemical (chlorine dioxide [ClO2] and peroxyacetic acid [PAA]) and physical (ultraviolet [UV]-C irradiation) inactivation methods on various food-contact surfaces (stainless steel [SS] and polypropylene [PP]) and foods (lettuce, chicken breast, and salmon) contaminated with human coronavirus 229E (HCoV-229E). Treatments with the maximum concentration of ClO2 (500 ppm) and PAA (200 ppm) for 5 min achieved >99.9% inactivation on SS and PP. At 200 ppm ClO2 for 1 min on lettuce, chicken breast, and salmon, the HCoV-229E titers were 1.19, 3.54, and 3.97 log10 TCID50/mL, respectively. Exposure (5 min) to 80 ppm PAA achieved 1.68 log10 reduction on lettuce, and 2.03 and 1.43 log10 reductions on chicken breast and salmon, respectively, treated with 1500 ppm PAA. In the carrier tests, HCoV-229E titers on food-contact surfaces were significantly decreased (p < 0.05) with increased doses of UV-C (0-60 mJ/cm2) and not detected at the maximum UV-C dose (Detection limit: 1.0 log10 TCID50/coupon). The UV-C dose of 900 mJ/cm2 proved more effective on chicken breast (>2 log10 reduction) than on lettuce and salmon (>1 log10 reduction). However, there were no quality changes (p > 0.05) in food samples after inactivation treatments except the maximum PAA concentration (5 min) and the UV-C dose (1800 mJ/cm2).

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.

Efficacy and Quality Attributes of Antimicrobial Agent Application via a Commercial Electrostatic Spray Cabinet To Inactivate Salmonella on Chicken Thigh Meat

ABSTRACT

Salmonella is a foodborne pathogen associated with poultry meat. This study aimed to determine the efficiency and quality attributes of two antimicrobial agents to reduce Salmonella on raw chicken meat when applied individually and in combination using an electrostatic spray cabinet. Thus, 5 log CFU/g of nonpathogenic, rifampin-resistant Salmonella Typhimurium was inoculated on skinless, boneless, raw chicken thigh meat and passed through an electrostatic spray cabinet while being sprayed with 5% lauric arginate (LAE), and 100, 1,000, 1,500, and 1,750 ppm of peracetic acid (PAA). Spraying of 5% LAE for 45 s significantly reduced Salmonella by 5 log (P < 0.05). The 1,500 ppm of PAA reduced Salmonella significantly within 45 s (1.157 log). Spraying of 1,500 ppm of PAA followed by LAE within 15 s reduced Salmonella significantly more than vice versa (P < 0.05). The color, water holding capacity, and texture did not differ significantly but resulted in significantly strong aroma and flavor. Both LAE and PAA efficiently reduced Salmonella when applied in an electrostatic spray cabinet on raw chicken thigh meat. The results suggest that the sequential order of application of antimicrobial agents is important to improve the safety and quality of raw chicken thigh meat.

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Effects of lactic, malic and fumaric acids on Salmonella spp. counts and on chicken meat quality and sensory characteristics

The aim of this work was to assess the effectiveness of dipping chicken breast in lactic, malic and fumaric acid 3% solutions for 15 s on Salmonella counts, as well as on chicken meat quality and sensory characteristics. All three treatments effectively reduced Salmonella counts. The values of Salmonella log reduction were 2.22, 1.55 and 1.30 log CFU/g for fumaric, malic and lactic treatments, respectively. Although fumaric acid was the most effective for reducing Salmonella counts, chicken meat quality and sensory characteristics were significantly affected, even in cooked samples. Conversely, malic and lactic acids treatments caused minimal changes in chicken meat quality and sensory characteristics compared to control samples. This study shows effective alternatives to reduce Salmonella contamination on chicken breast fillets, although further studies should be considered to improve the effects on quality and sensory attributes.

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.

Optimization of the In Vitro Bactericidal Effect of a Mixture of Chlorine and Sodium Gallate against Campylobacter spp. and Arcobacter butzleri

ABSTRACT

Campylobacter spp. and Arcobacter butzleri are foodborne pathogens associated with the consumption of contaminated raw chicken meat. At the industry level, the combination of new and common antimicrobials could be used as a strategy to control the presence of pathogens in chicken carcasses. The objective of this study was to determine the bacteriostatic and bactericidal effects of a mixture of chlorine (Cl) and sodium gallate (SG) on a mixture of two Campylobacter species (Campylobacter jejuni and Campylobacter coli) and A. butzleri. Using a central composite experimental design, it was established that the optimum inhibitory SG-Cl concentration for Campylobacter spp. was 44 to 45 ppm. After 15 h of incubation, Campylobacter species growth was reduced by 37.5% and the effect of Cl was potentiated by SG at concentrations above 45 ppm. In the case of A. butzleri, optimum levels of 28 and 41 ppm were observed for SG and Cl, respectively; no synergism was reported, as this bacterium was more sensitive to lower Cl concentrations than Campylobacter. After a 20-min pretreatment with peracetic acid (50 ppm), the optimum condition to achieve a >1.0-Log CFU/mL reduction of Campylobacter spp. was exposure to 177 ppm of Cl and 44 ppm of SG for 56 min. As A. butzleri showed lower resistance to the bacteriostatic effect of the Cl-SG combination, it was assumed that optimum bactericidal conditions for Campylobacter spp. were effective to control the former; this was confirmed with subsequent validation of the model. The SG-Cl combination has bactericidal properties against Campylobacter and A. butzleri, and it may be a useful strategy to improve sanitary practices applied in the poultry industry.

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Characterization of Salmonella Isolates Recovered from Stages of the Processing Lines at Four Broiler Processing Plants in Trinidad and Tobago

This cross-sectional study determined the prevalence, characteristics, and risk factors for contamination of chicken with Salmonella at four operating broiler processing plants in Trinidad. Standard methods were used to isolate and characterize the Salmonella isolates. The overall prevalence of Salmonella at the four processing plants was 27.0% (107/396). The whole carcass enrichment (WCE) method yielded a statistically significantly (p = 0.0014) higher frequency of isolation (53.9%; 97/180) than the whole carcass rinse (35.0%; 63/180) and neck skin methods (42.2%; 38/90). S. enterica serotypes Enteritidis, Javiana, and Infantis were the predominant serotypes isolated accounting for 20.8%, 16.7% and 12.5%, respectively, of the serotyped isolates. Risk factors included the use of over 100 contract farmers (OR 4.4), pre-chiller (OR 2.3), addition of chlorine to chiller (OR 3.2), slaughtering sick broilers (OR 4.4), and flocks with >50% mortality. Multi-drug resistance was detected in 12.3% (14/114) of the isolates of Salmonella. Resistance was high to kanamycin (85.7%) and doxycycline (74.6%) but low to amoxicillin-clavulanic acid (2.4%) and sulphamethoxazole-trimethoprim (0.8%). The occurrence of resistant Salmonella in chickens processed at commercial broiler processing plants has implications for salmonellosis and therapeutic failure in consumers of improperly cooked contaminated chickens from these plants in the country.

Ethyl Lauroyl Arginate (LAE): Antimicrobial Activity of LAE-Coated Film for the Packaging of Raw Beef and Pork

In this study, the antimicrobial activity of an ethyl lauroyl arginate- (LAE®-) coated film applied to the packaging of raw beef and pork was evaluated. Two different trials were performed for each meat species, aiming to evaluate the functionality of the film in contrasting the development of the natural microflora and of a specific target agent, Escherichia coli ATCC 25922. In the first trial, LAE-coated packaging was applied to test its activity towards the natural meat microflora over a period of 24 days at 6-7°C. The comparison with the control sample series showed a slight initial inhibitory activity on total viable count, followed by a growing trend. In the second trial, the antimicrobial activity of the LAE-coated film was evaluated on raw beef and pork voluntarily inoculated with Escherichia coli: an initial killing effect on E. coli was detected in both pork and beef meat (reduction around 0.7 and 1 log CFU/g, respectively), followed by a stable trend for the following storage period (24 days).

Bactericidal effect of glycerol monolaurate complex disinfectants on Salmonella of chicken

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

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.

Prevalence of Salmonella enterica on poultry processing equipment after completion of sanitization procedures

Salmonella is a poultry-borne pathogen that causes illness throughout the world. Consequently, it is critical to control Salmonella during the process of converting broilers to poultry meat. Sanitization of a poultry processing facility, including processing equipment, is a crucial control measure that is utilized by poultry integrators. However, prevalence of Salmonella on equipment after sanitization and its potential risk to food safety has not been evaluated thoroughly. Therefore, the objective of this study was to evaluate the persistence of Salmonella on poultry processing equipment before and following cleaning and sanitization procedure. A total of 15 locations within 6 commercial processing plants were sampled at 3 time points: (A) after processing; (B) after cleaning; and (C) after sanitization, on 3 separate visits for a total of 135 samples per plant. Salmonella-positive isolates were recovered from samples using the United States Department of Agriculture MLG 4.09 conventional method. Presumptive Salmonella colonies were subjected to biochemical tests for confirmation. Salmonella isolates recovered after sanitization were serotyped and tested for the presence of specific virulence genes. A completely randomized design with a 6 × 3 × 15 factorial arrangement was utilized to analyze the results for Salmonella prevalence between processing plants. Means were separated using Fishers protected least significant difference when P ≤ 0.05. For Salmonella prevalence between processing plants, differences (P < 0.0001) were observed in the 6 plants tested where the maximum and minimum prevalence was 29.6 and 7.4%, respectively. As expected, there was a difference (P < 0.0001) in the recovery of Salmonella because of sampling time. Salmonella prevalence at time A (36%) was significantly higher, whereas there was no difference between time B (12%) and C (9%). There was a location effect (P < 0.0001) for the prevalence of Salmonella with the head puller, picker, cropper, and scalder having a significantly higher prevalence when compared with several other locations. At sampling time C, a trend toward a difference (P = 0.0899) was observed for Salmonella prevalence between the 6 plants, whereas significant differences were observed because of location (P = 0.0031). Five prominent Salmonella enterica serovars were identified, including Kentucky, Schwarzengrund, Enteritidis, Liverpool, and Typhimurium with S. Kentucky being the most prevalent. PCR analysis of 8 Salmonella virulence genes showed that the invA, sipB, spiA, sseC, and fimA were detected in all isolates, whereas genes carried on plasmids and/or fimbriae varied remarkably among all isolates. This study established Salmonella prevalence and persistence in poultry processing facilities after antimicrobial application through sanitization procedures which could result in contamination of poultry carcasses and food safety risks because of poultry meat.

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.

The Effect of Sanitizers on Microbial Levels of Chicken Meat Collected from Commercial Processing Plants

Chicken meat can potentially become contaminated with bacteria at the processing plant. In Australia, there is currently a lack of knowledge on the parameters and indications of use of non-chlorine based treatments in the chicken meat processing plants. Chlorine is widely used as a sanitizer in Australian chicken meat processing plants but due to occupational health and safety concerns and consumer perception, there is a need to identify alternative sanitizers. This study aimed to assess the efficacy of four different sanitizers in reducing the microbial load from naturally contaminated chicken meat carcasses collected from the processing plants in South Australia. There was a significant variation in a load of Campylobacter and total viable count (TVC) between samples collected from two different processing plants and within carcass batches collected from the same plant that was tested during the study. All sanitizers generally reduced the load of Campylobacter on chicken meat carcasses. Treatment with acidified sodium chlorite significantly reduced the level of Salmonella enterica serovars at all temperatures tested during this study. These findings are helpful to the industry for selection of the appropriate sanitizers. Findings are also useful for the regulatory authorities in Australia for providing approval for the use of sanitizers.

Sanitization of Chicken Frames by a Combination of Hydrogen Peroxide and UV Light To Reduce Contamination of Derived Edible Products

Chicken carcass frames are used to obtain mechanically separated chicken (MSC) for use in other further processed food products. Previous foodborne disease outbreaks involving Salmonella-contaminated MSC have demonstrated the potential for the human pathogen to be transmitted to consumers via MSC. The current study evaluated the efficacy of multiple treatments applied to the surfaces of chicken carcass frames to reduce microbial loads on noninoculated frames and frames inoculated with a cocktail of Salmonella enterica serovar Enteritidis and Salmonella enterica serovar Typhimurium. Inoculated or noninoculated frames were left untreated (control) or were subjected to treatment using a prototype sanitization apparatus. Treatments consisted of (i) a sterile water rinse, (ii) a water rinse followed by 5 s of UV-C light application, or (iii) an advanced oxidation process (AOP) combining 5 or 7% (v/v) hydrogen peroxide (H₂O₂) with UV-C light. Treatment with 7% H₂O₂ and UV-C light reduced numbers of aerobic bacteria by up to 1.5 log CFU per frame (P < 0.05); reductions in aerobic bacteria subjected to other treatments did not statistically differ from one another (initial mean load on nontreated frames: 3.6 ± 0.1 log CFU per frame). Salmonella numbers (mean load on inoculated, nontreated control was 5.6 ± 0.2 log CFU per frame) were maximally reduced by AOP application in comparison with other treatments. No difference in Salmonella reductions obtained by 5% H₂O₂ (1.1 log CFU per frame) was detected compared with that obtained following 7% H₂O₂ use (1.0 log CFU per frame). The AOP treatment for sanitization of chicken carcass frames reduces microbial contamination on chicken carcass frames that are subsequently used for manufacture of MSC.

Modeling the Reduction and Cross-Contamination of Salmonella in Poultry Chilling Process in China

: The study was to establish a predictive model for reduction and cross-contamination of Salmonella on chicken in chilling process. Reduction of Salmonella on chicken was 0.75 ± 0.04, 0.74 ± 0.08, and 0.79 ± 0.07 log CFU/g with 20, 50, and 100 mg/L of chlorine, respectively. No significant differences of bacterial reductions with 20-100 mg/L of chlorine were found and a Normal (-0.75, 0.1) distribution could describe the uncertainty of bacterial reductions. Inoculated and non-inoculated chicken samples were washed together and bacterial transfer rates among them were 0.13%-0.004% with 20-100 mg/L of chlorine. No significant differences of transfer rates with 50-100 mg/L of chlorine were observed and a Triangle (-2.5, -1.5, -1.1) distribution could describe the log transfer rate. Additionally, a 3-factor response surface model based on the central composite design was developed to evaluate the effects of initial contamination level (1-5 log CFU/g), pre-chill incidence (3%-40%) and chlorine concentration (0-100 mg/L) on post-chill incidence. The post-chill incidences in these treatments were within 30%-91.7%. The developed model showed a satisfactory performance to predict the post-chill incidence as evidenced by statistical indices (pseudo-R2 = 0.9; p < 0.0001; RMSE = 0.21) and external validation parameters (Bf = 1.02; Af = 1.11).

Effects of Cetylpyridinium Chloride and Peroxyacetic Acid Treatment of Broiler Frames on Salmonella Incidence and Mechanically Separated Chicken Quality

Mechanically separated chicken (MSC) has a high incidence of Salmonella since it is separated and homogenized from multiple broiler frames. In addition, limited research has been reported on the reduction of naturally contaminated Salmonella on chicken carcasses or chicken frames. Therefore, broiler frames were treated with antimicrobial solutions of 0.1% peroxyacetic acid (PAA) or 0.5% cetylpyridinium chloride with Citrilow (CPC) for contact times of 30, 60, 90, or 120 s and evaluated for their effectiveness at reducing the incidence of naturally contaminated Salmonella spp. on broiler frames and decreasing Salmonella counts on inoculated frames that were ground and sieved into MSC. Treatment times for PAA and CPC did not affect (P > 0.05) % incidence of Salmonella on naturally contaminated broiler frames. While CPC30 showed a greater % reduction in incidence (P < 0.05) than PAA30, CPC90 and CPC120 did not differ (P > 0.05) from PAA90 and PAA120. However, the CPC treatments imparted a greater decrease in incidence of Salmonella on frames than PAA. For inoculated frames, both antimicrobial treatments at all treatment times had fewer (P < 0.05) Salmonella counts in MSC than their controls. Treated MSC samples were evaluated for pH, color, cook loss and protein bind. On average, CPC treatments were lighter (CIE L*; P < 0.05) than PAA treatments, and PAA treatments were more red (CIE a*) and more yellow (CIE b*; P < 0.05) than CPC treatments. All treatments produced MSC with lesser hue values than their controls. Protein bind and cook loss results indicated that the PAA treatments had no significant impact on MSC quality. Frames that were treated with CPC for 60 s yielded less protein bind than the control, which indicates less protein functionality.