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.

Poultry Processing Interventions Reduce Salmonella Serovar Complexity on Postchill Young Chicken Carcasses as Determined by Deep Serotyping.

Nearly 20% of salmonellosis cases are attributed to broilers, with renewed efforts to reduce Salmonella during broiler production and processing. A limitation to Salmonella culture is that often a single colony is picked for characterization, favoring isolation of the most abundant serovar found in a sample, while low abundance serovars can remain undetected. We used a deep serotyping approach, CRISPR-SeroSeq (serotyping by sequencing the clustered regularly interspaced palindromic repeats), to assess Salmonella serovar complexity during broiler processing and to determine the impact of antimicrobial interventions upon serovar population dynamics. Paired hot rehang and postchill young chicken carcasses were collected from establishments across the United States from August to November 2022. CRISPR-SeroSeq was performed on Salmonella culture-positive hot rehang (n = 153) and postchill (n = 38) samples, including 31 paired hot rehang and postchill samples. Multiple serovars were detected in 48.4% (74/153) and 7.9% (3/38) of hot rehang and postchill samples, respectively. On average, hot rehang carcasses contained 1.6 serovars, compared to 1.1 serovars at postchill (Mann Whitney U, p = 0.00018). Nineteen serovars were identified with serovar Kentucky the most common at hot rehang (72.5%; 111/153) and postchill (73.7%; 28/38). Serovar Infantis prevalence was higher at hot rehang (39.9%; 61/153) than in postchill (7.9%; 3/38). At hot rehang, serovar Enteritidis was outnumbered by other serovars 81.3% (13/16) of the time but was always the single or most abundant serovar detected when it was present at postchill (n = 5). We observed 98.4% (188/191) concordance between traditional isolation with serotyping and CRISPR-SeroSeq. Deep serotyping was able to explain serovar discrepancies between paired hot rehang and postchill samples when only traditional isolation and serotyping methods were used. These data demonstrate that processing interventions are effective in reducing Salmonella serovar complexity.

ß-Lactamase Producing Escherichia coli Encoding blaCTX-M and blaCMY Genes in Chicken Carcasses from Egypt.

Escherichia coli with multidrug resistance and ß-lactamase genes may constitute a great public health hazard due to the potential for their transmission to humans through the food chain. This study determined the prevalence, antibiotic resistance profiles, phylogroups, and ß-lactamase genes of E. coli isolates from chicken carcasses marketed in Mansoura, Egypt. Interestingly, E. coli was detected in 98% (98/100) of the chicken carcasses examined, which seemed among the highest contamination rates by E. coli worldwide. From the 425 genetically verified uidA gene-positive E. coli, 85 isolates were further studied for antimicrobial resistance profiles, phylogroups, and ß-lactamase genes. Interestingly, 89.41% of E. coli (76/85) strains tested against 24 different antibiotics were multidrug-resistant. Of the examined 85 E. coli isolates, 22 (25.88%) isolates harbored blaCTX-M and were resistant to ampicillin, cefazoline, and ceftriaxone, while three of them were resistant to ceftazidime besides. Nine (10.59%) E. coli strains harbored AmpC- ß-lactamase blaCMY and were resistant to ampicillin. One isolate co-carried blaCMY and blaCTX-M genes, though it was negative for the blaTEM gene. Of the 35 isolates that harbored either extended-spectrum ß-lactamase (ESBL) and/or AmpC ß-lactamase genes, six strains (17.14%) were assigned to pathogenic phylogroup F and one to phylogroup E, whereas 28 (80%) isolates belonged to commensal phylogenetic groups.

The effect of natural antimicrobials on the Campylobacter coli T6SS+/- during in vitro infection assays and on their ability to adhere to chicken skin and carcasses.

Reducing the Campylobacter load on poultry carcasses represents a major tasks for the industry as its ability to reduce their presence is of major interest aiming to increase consumer safety. This study investigated the ability of a mixture of natural antimicrobials (A3001) to reduce the adherence of the T6SS+/-C. coli isolates (NC1hcp-, NC2 hcp- and NC3 hcp+) to chicken neck skin and whole carcasses. Overall, the antimicrobial mixture induced a significant reduction in the capability of our C. coli isolates to colonise the chicken skin (p < 0.05) and carcasses (p < 0.0001) but with a greater effect (≈3 log reduction) on the NC3 isolate. Using the HCT-8 in vitro infection model we also show that at a concentration of 0.5% A3001, the impact on the NC3 isolate is accompanied by the downregulation of the hcp gene (p = 0.0001), and indicator of the T6SS presence. The results described herein also indicated that these isolates are highly resistant to H2O2, up to 20 mM, suggesting a high resilience to environmental stresses. In summary our study shows that natural antimicrobials can reduce the ability of T6SS positive chicken C. coli isolates to adhere to chicken skin or to the whole carcass and to infect epithelial cells in vitro and could be considered a potential intervention at processor level.

Proteus mirabilis causing cellulitis in broiler chickens.

Given the need to understand the virulence profile of Proteus mirabilis isolates from cellulitis in broiler chickens and their ability to cause lesions, the present study aimed to characterize genotypically and phenotypically the virulence profiles of two strains of P. mirabilis isolated from cellulitis in broilers, as well as to evaluate their ability to experimentally reproduce the lesions in vivo. The strain with the highest virulence potential (LBUEL-A33) possessed mrpA, pmfA, ucaA, atfA (fimbriae), zapA, ptA (proteases), hpmA (hemolysin), and ireA (siderophore) genes, formed a very strong biofilm, and expressed the pattern of aggregative adhesion and cytotoxicity in Vero cells. The strain with the lowest virulence potential (LBUEL-A34) did not present the pmfA and ucaA genes, but expressed the pattern of aggregative adhesion, formed a strong biofilm, and did not show cytotoxicity. Both strains developed cellulitis in an animal model within 24 h post-inoculation (PI), and the degree of lesions was not significantly altered up to 120 h PI. The LBUEL-A33 strain was also inoculated in combination with an avian pathogenic Escherichia coli (APEC 046), and the lesions showed no significant changes from the individual inoculation of these two strains. Histological analysis showed that the LBUEL-A33 strain developed characteristic cellulitis lesions. Thus, both strains of P. mirabilis isolated in our study have several virulence factors and the ability to develop cellulitis in broilers.

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

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

Antimicrobial Resistance Profile of Salmonella Isolates in Chicken Carcasses in Dakar, Senegal.

The incidence of the Salmonella contamination of poultry products in Senegal is unknown. Salmonella contamination and antimicrobial drug resistance profiles in chicken carcasses were investigated. Between July 2012 and July 2013, three types of chicken carcasses (broilers, laying hens, and premises chickens) obtained from retailers in the markets of Dakar and its suburbs were tested for Salmonella contamination. Salmonella strains were isolated from 300 chicken carcasses according to International Organization for Standardization ISO 6579 (2002) guidelines. In these samples, 273 isolates were obtained, belonging to 22 serovars, and 53% samples were contaminated with at least 1 serovar. Standardized techniques were used for the susceptibility testing and serotyping of isolates. Hygiene conditions, in terms of the cleanliness of stalls, the packing of chicken carcasses in bags, and the maintenance of the cold chain at the stall, were moderately poor. The three serovars most frequently identified were Salmonella Istanbul (28%), Salmonella Brancaster (19%), and Salmonella Kentucky (13%). Overall, 21% of isolates were resistant to quinolones and fluoroquinolones. Serovar Istanbul was resistant to tetracycline (TE) and trimethoprim + sulfamethoxazole (SXT). Serovars Brancaster and Kentucky were resistant to betalactams and to quinolones or fluoroquinolones. The uncommon serovar Senftenberg had the strongest resistance profile, displaying resistance to betalactams including imipenem (IMP). Large numbers of isolates were resistant to TE (66%) and SXT (47%). Resistance to cephalosporins (5%), chloramphenicol (2%), gentamicin (8%), and IMP (1%) was less frequent. A large proportion of the broilers sold in Dakar markets were contaminated with Salmonella. This situation probably resulted from poor hygiene conditions in chicken farms and slaughterhouses and from breaks in the cold chain at some point in the distribution of poultry products.

Comparison of the Antimicrobial and Sanitizer Resistance of Salmonella Isolates from Chicken Slaughter Processes in Korea.

Salmonella is a foodborne pathogen worldwide. Outbreaks of Salmonella are commonly associated with consumption of contaminated foods such as poultry products. Therefore, the objective of this study was to determine the occurrence, biofilm formation, antibiotic resistance, and sanitizer resistance of Salmonella enterica isolated from chicken carcasses. A total of 318 samples were collected from 15 chicken slaughterhouses in 8 provinces of Korea. They were then examined for Salmonella contamination. S. enterica isolates were tested for their susceptibilities to 15 antimicrobials by broth microdilution method. Their biofilm formation ability and resistance to sanitizers were also evaluated. Eighty-two isolates of S. enterica were obtained from the 318 samples. There were 14 serotypes and 2 untypable isolates. Fifty-seven (69.5%) isolates were resistant to at least one antibiotic while 30 (36.6%) isolates were resistant to 5 or more antibiotics. Two S. Senftenberg and 3 S. Montevideo isolates exhibited considerable biofilm formation ability (A600 >0.2) following incubation in Luria-Bertani (LB) broth for 48 h. Biofilm cell survival and recovery growth assay after sanitization showed that most isolates were highly susceptible to 2.5% lactic acid and 0.1% cetylpyridinium chloride. Therefore, lactic acid and cetylpyridinium chloride might be alternatively or additionally used in addition to chlorine-based sanitizers that are frequently used to reduce Salmonella contamination of chicken carcasses. Our results provide basic information on the distribution of Salmonella serotypes in chicken slaughterhouses. This study also highlights the necessity to improve farming practices and use antimicrobial agents cautiously. This study also suggests that sanitization during the slaughtering process might be necessary to reduce Salmonella contamination of chicken carcasses.

Application of loop-mediated isothermal amplification with propidium monoazide treatment to detect live Salmonella in chicken carcasses.

Raw chicken products are major causes of human foodborne salmonellosis worldwide. In particular, there is a significant risk of human exposure to Salmonella originating from the chicken slaughtering process. Controlling the contamination of chicken carcasses by Salmonella has been a considerable challenge in chicken-slaughtering facilities and involves routine microbiological monitoring using reliable detection methods. Simple and rapid detection methods, particularly those capable of determining cell viability, will significantly facilitate routine monitoring of Salmonella Here, we report an invA-based loop-mediated isothermal amplification method coupled with a simple propidium monoazide treatment (PMA-LAMP) for simple and rapid detection and quantification of viable Salmonella in rinse water of chicken carcasses. In this study, PMA-LAMP consistently gave negative results for isopropanol-killed Salmonella with concentrations up to 8.0 × 106 CFU/reaction. The detection limit of PMA-LAMP was 8.0 × 101 CFU/reaction with viable Salmonella in both pure culture and rinse water of chicken carcasses, and 10-fold lower than a conventional polymerase chain reaction coupled with PMA (PMA-PCR) targeting invA There was a high correlation (R2 = 0.99 to 0.976) between LAMP time threshold (TT) values and viable Salmonella with a quantification range of 1.0 × 103 to 1.0 × 108 CFU/mL in pure culture and rinse water of chicken carcasses. The PMA-LAMP assay took less than 2 h to detect Salmonella contaminated in test samples. Therefore, this simple and rapid method will be a very useful tool to detect live Salmonella contamination of chicken carcasses without pre-enrichment at the slaughterhouse where sanitizing treatments are commonly used.

[Molecular subtyping and traceability analysis of Campylobacter jejuni isolated from chicken carcasses in slaughterhouses by FAFLP].

OBJECTIVE: To implement molecular subtyping and traceability analysis of Campylobacter jejuni isolated from chicken carcasses in slaughterhouses in some provinces. METHODS: A total of 72 Campylobacter jejuni strains were subtyped by fluorescent amplified fragment length polymorphism with Hind Ⅲ and Hha Ⅰ. After electrophoresis results were analyzed with Gene Marker V1. 80, Cluster analysis was performed by Bio Numerics software to further establish tracing analysis database of Campylobacter jejuni. RESULTS: 241 polymorphic fragments were yielded among 72 islolates, while most isolates gave 80 to 100 fragments. 72 FAFLP types were yielded among 72 strains with a resolution of 100%. According to 70% similarity, 72 strains were assigned to 11 clusters. The lowest similarity between clusters was 56. 9%, and the highest similarity was 94. 9%. According to 80% similarity, cluster A could be divided into 5 sub-clusters, and cluster B was divided into 15 sub-clusters. Strains in the same sub-cluster displayed complete regional homology. CONCLUSION: FAFLP is suitable for molecular subtyping andtraceability analysis of Campylobacter jejuni for its high resolution and good regional homology of cluster analysis.

[Antimicrobial resistance analysis and mechanism of Salmonella recovered from retail chicken carcasses in Beijing in summer, 2013].

OBJECTIVE: Research were carried out to determine the antimicrobial resistance and mechanism of Salmonella isolates recovered from retail chicken carcasses in Beijing in summer, 2013. METHODS: Broth microdilution method were used for antimicrobial susceptibility testing to obtain the minimal inhibitory concentration( MICs)against 11 antimicrobial compounds which belongs to 8 categories and 166 Salmonella strains isolated from 33 retail chicken carcasses in Beijing in summer, 2013 were tested. Cephalosporin resistant isolates were evaluated by ESBLs confirmation test, also resistance mechanism analysis was subjected to ciprofloxacin and cefotaxime co-resistant Salmonella isolates. RESULTS: 94. 6% isolates were resistant to at least one antimicrobial and 58. 4% were identified as multi-drug resistant strains. The highest rate of resistance was 92. 2% against nalidixic acid, followed by ampicillin( 48. 8%), ampicillin-sulbactam( 44. 0%), tetracycline( 44. 0%). There were 27 antimicrobial resistance spectrums with NAL and NAL-AMP-SAM being dominant spectrums. Totally, 41 ESBLs positive strains which contained 38 ciprofloxacin resistant isolates were recovered from 47 cefotaxime resistant strains. Detection of quinolones and ß-lactams resistant genes for 38 ciprofloxacin and cefotaxime co-resistant and ESBLs positive Salmonella isolates indicate that QRDRs/PMQR/ESBLs antimicrobial resistance mechanism existed in these strains. Point mutations in gyrA and parC were identified in 37 isolates, and 38 isolates tested all contained PMQR genes such as qnrB、qnrS、oqxAB and aac( 6 ')-Ib-cr genes with a few mutations, while CTX-M( n = 35), TEM( n = 20), OXA( n = 36) type ß-lactamases were detected. CONCLUSION: High level antimicrobial resistance and complicated mechanism existed among Salmonella recovered from retail chicken carcasses in Beijing in summer, 2013. In order to protect public health, tendency and further mechanism on antimicrobial resistance and transmissibility should be described deeply by on-going surveillance and research, while rational drug use regulatory managements should be carried out in the overall process of chicken production, slaughtering, transportation and marketing, as well as clinical treatment for human Salmonella infections.

Investigation of enrofloxacin residues in broiler tissues using ELISA and LC-MS/MS.

This study investigated the efficiency of an enrofloxacin ELISA test kit to detect the presence of enrofloxacin residues in broiler tissues compared with LC-MS/MS. Broiler tissues from 72 samples consisting of 60 breast muscle, six pools of livers (500 g each) and six pools of kidneys (500 g each) were obtained from six different slaughterhouses. Breast muscle from 10 carcasses and pools of livers and kidneys from approximately 200 carcasses of the same flock were collected from each slaughterhouse. ELISA and HPLC were used to identify and quantify the contamination of the samples with enrofloxacin. A total of 72% of the analysed samples contained enrofloxacin residues detected by the ELISA and 22.2% were detected by LC-MS/MS. The mean values of enrofloxacin contamination found in chicken breast by ELISA and HPLC were 8.63 and 12.25 µg kg(-1), respectively. None of the samples exceeded the maximum limit of 100 µg kg(-1) by both methods set by the European Union as well as the Brazilian Agriculture Ministry. All positive samples for enrofloxacin residues detected by LC-MS/MS were also positive by ELISA. These data confirm the efficiency of the ELISA test, and suggest its use as a screening method for enrofloxacin residues in poultry tissues due to its quick results, low price and ease of applicability.

Arcobacter butzleri: first isolation report from chicken carcasses in costa rica

Arcobacter butzleri isolation from chicken carcasses in Costa Rica is reported for the first time. The isolated strains (P and R) were presumptively identified by their phenotypic characteristics. Definitive identification was made using a multiplex PCR assay for the simultaneous detection and identification of Arcobacter butzleri, Arcobacter cryaerophilus and Arcobacter skirrowii. These first isolations indicate the necessity of further investigation about the prevalence, distribution, ecology and interactions with human beings of this and other Arcobacter species.

Arcobacter butzleri: first isolation report from chicken carcasses in costa rica.

Arcobacter butzleri isolation from chicken carcasses in Costa Rica is reported for the first time. The isolated strains (P and R) were presumptively identified by their phenotypic characteristics. Definitive identification was made using a multiplex PCR assay for the simultaneous detection and identification of Arcobacter butzleri, Arcobacter cryaerophilus and Arcobacter skirrowii. These first isolations indicate the necessity of further investigation about the prevalence, distribution, ecology and interactions with human beings of this and other Arcobacter species.

Occurrence of Salmonella spp: in broiler chicken carcasses and their susceptibility to antimicrobial agents / Ocorrência de Salmonella spp: em carcaças de frango e sua suscetibilidade a agentes antimicrobianos

The present study was carried out to evaluate the occurrence of Salmonellae in broiler chicken carcasses and to determine the antimicrobial resistance profile of the isolated strains. Twenty-five out of the 260 broiler chicken carcasses samples (9.6 percent) were positive for Salmonella. S. Enteritidis was the most frequent serovar. Nineteen Salmonella isolates were tested for antimicrobial resistance, and the results indicated that 94.7 percent were resistant to at least one antimicrobial agent. Resistance to streptomycin (73.7 percent), nitrofurantoin (52.3 percent), tetracycline (31.6 percent), and nalidixic acid (21 percent) were the prevalent amongst Salmonella strains tested.

O presente estudo teve como objetivo verificar a ocorrência de Salmonellae em amostras de carcaças de frango e a suscetibilidade dos isolados a agentes antimicrobianos. Das 260 carcaças analisadas, 25 (9,6 por cento) foram positivas para Salmonella. Salmonella Enteritidis foi o sorovar predominante. Com relação à suscetibilidade a agentes antimicrobianos, 94,7 por cento das cepas de Salmonella testadas, apresentaram resistência a um ou mais agentes antimicrobianos. Os perfís de resistência mais comumente observados entre os isolados foram a resistência à estreptomicina (73,7 por cento), nitrofurantoína (52,3 por cento), tetraciclina (31,6 por cento) e ácido nalidíxico (21 por cento).

Occurrence of Salmonella spp. in broiler chicken carcasses and their susceptibility to antimicrobial agents.

The present study was carried out to evaluate the occurrence of Salmonellae in broiler chicken carcasses and to determine the antimicrobial resistance profile of the isolated strains. Twenty-five out of the 260 broiler chicken carcasses samples (9.6%) were positive for Salmonella. S. Enteritidis was the most frequent serovar. Nineteen Salmonella isolates were tested for antimicrobial resistance, and the results indicated that 94.7% were resistant to at least one antimicrobial agent. Resistance to streptomycin (73.7%), nitrofurantoin (52.3%), tetracycline (31.6%), and nalidixic acid (21%) were the prevalent amongst Salmonella strains tested.

A Rapid Microbiological Method for Enumeration of Pseudomonas fluorescens from Broiler Chicken Carcasses.

A method to selectively enumerate Pseudomonas fluorescens from fresh chicken carcasses in less than 24 h using capacitance microbiology was developed. Capacitance assays were conducted on whole-carcass rinses at 25°C using brain heart infusion broth (BHI) containing 25 µg of Irgasan per ml to obtain a detection time. The capacitance samples were spread plated on plate count agar for isolation and identification. From plates with the highest dilution, from each carcass, 4 colonies were randomly selected and identified. Seven species of bacteria including Pseudomonas fluorescens were responsible for capacitance detection times. Various antibiotics and chemicals were added to basal media or brain heart infusion broth with Irgasan and were evaluated to select for the growth of P. fluorescens . BHI broth containing 4 µg of nitrofurantoin, 120 µg of carbenicillin, and 25 µg of Irgasan, all per ml, was found to be optimal and was termed Pseudomonas fluorescens selective additive (PSA) (patent pending). In a second study, 12 carcasses were collected in each of three replicate trials. For each trial, 2 carcasses were sampled immediately and 2 were sampled after storage at 3°C on days 3, 6, 9, 12, and 15. The BHI-PSA broth was found to be excellent for enumeration of P. fluorescens from broiler chicken carcass rinses in assays using capacitance microbiology at 25°C. The time required to enumerate P. fluorescens for all samples (day 0 to 15) was <22.4 h. This method is rapid and would be a useful tool for determining the number of spoilage bacteria on fresh chicken and thus may possibly be used to predict the potential shelf life of fresh chicken and other foods of animal origin.

Drug Resistance of Enterobacteriaceae Isolated from Chicken Carcasses.

The antibiotic resistance profiles and transferable R factors of Salmonella and Escherichia coli isolates from 104 broiler carcasses taken from one processing plant were determined. Carcasses were sampled after immersion chilling. All samples were transported iced and immediately analyzed upon arrival to the laboratory. The resistance patterns of isolates to 12 antibiotics were determined (i.e., ampicillin, cephalothin, streptomycin, sulfisoxazole, trim-ethoprim-sulfamethoxazole, nalidixic acid, tetracycline, neomycin, chloramphenicol, gentamicin, colistin, and nitrofurantoin). Isolates resistant to one or more antibiotics were utilized as donors of resistance to completely antibiotic-sensitive strains, an E. coli K-12, F-, J5, azide-resistant strain and a Salmonella serovar Enteritidis. Transfer of the different R plasmids was confirmed by the determination of the resistance patterns of the transconjugants. Of the 93 Salmonella and 71 E. coli strains isolated from these samples, the largest numbers were resistant to tetracycline (52.7% and 49.3%), sulfisoxazole (45.2% and 42.3%), and streptomycin (37.6% and 39.4%). Large percentages of the Salmonella (33.3%) and the E. coli (30.0%) strains transferred all or part of their resistance to E. coli K-12 in mixed cultures. Great variation was observed between different strains in the frequency at which they transferred resistance. Resistance to tetracycline, sulfisoxazole, and streptomycin was found to be conferred by 31.7%, 29.8%, and 21.6% of the 19 R factors identified. No transfer of resistance to nalidixic acid, gentamicin, cephalothin, nitrofurantoin, and chloramphenicol was detected. When 30 antibiotic-resistant E. coli strains were cultured with a sensitive strain of Salmonella serovar Enteritidis,7 (23.3%) of the resistant strains were found capable of transferring R factors. Only 2 (6.7%) of the resistant strains could transfer R factors and unusual ß-galactosidase activity.

Reduction of Salmonella and Campylobacter on Chicken Carcasses by Changing Scalding Temperature.

Chickens were processed at three scalding temperatures, 52, 56, or 60°C, and the numbers of Salmonella and Campylobacter attached to the fully processed carcasses in each group were compared. For Salmonella , carcasses scalded at 52 or 56°C showed ~ 0.3 to 0.5 lower log numbers than carcasses at 60°C (P < 0.05). There were no significant differences between the carcasses at 52 and 56°C. For Campylobacter , carcasses scalded at 56°C showed ~ 0.7 lower log counts than the carcasses at 60°C (P < 0.05) in the first two trials; however, no difference was observed in a third trial. Although the reduction of bacteria attached to the chicken carcasses was not as great as shown in previous attachment studies using skin samples (1.0 to 1.4 log cycles), these results show that reductions in bacterial numbers on chicken carcasses can be achieved by simply changing the scalding temperature.

Effect of Trisodium Phosphate on Campylobacter Attached to Post-Chill Chicken Carcasses.

Trisodium phosphate (TSP) was evaluated as a means to reduce Campylobacter on chicken carcasses. Post-chill chicken carcasses were dipped into a 10% TSP solution at 50°C for 15 s. After storing the TSP-treated carcasses for 0, 1 or 6 days at 4°C, the carcasses were subjected to the recovery of Campylobacter . The incidence and reduction of Campylobacter attached to the carcasses were measured using a nitrocellulose (NC) membrane lift, conventional culture method, and a most probable number (MPN) technique. In trials 1 and 2, the incidence of Campylobacter was measured. For 1 day-stored groups, Campylobacter was present on 96 and 100% of control carcasses and present on 24 and 28% of TSP-treated carcasses as measured by NC membrane lift method. The reduction was less (4 to 36%) when measured by culture method. For carcasses immediately subjected for the recovery of cells after treatment, there was no difference between TSP-treated and control carcasses by either NC membrane or culture method. In trial 3, the reduction levels of Campylobacter were quantified by using a MPN method. The levels of Campylobacter on carcasses were decreased by 1.5 and 1.2 logs in 1- and 6-day stored, TSP-treated carcasses, respectively (p < 0.05). However, TSP treatment at 10°C reduced the level of Campylobacter only by 0.16 log (p > 0.10).