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Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Salmonella is the most burdensome foodborne pathogen in the USA and a major causal agent of foodborne outbreaks. Detection of a pathogen such as Salmonella can be achieved within a few hours using commercially available rapid methods, but the sample preparation is time consuming and may require multiple days. We have developed and successfully tested an accelerated sample preparation method based on microfiltration, in some cases preceded by a short enrichment step, for the rapid detection of selected pathogens. The time-frame of the overall process, from sample preparation (i.e., food rinse or homogenate preparation, microbial enrichment, and filtration steps) to detection is 8 h or less. While microfiltration has been practiced for 70 years, the complex interactions between food substances and filter membrane surfaces have shown that food pretreatment methods need to be developed on a case by case basis for the recovery of bacteria from food homogenates and/or rinses. We have also demonstrated that addition of protease to treat homogenates of different poultry products prior to microfiltration avoids the rapid decrease in flux that otherwise occurs during microfiltration. This protease treatment minimizes filter clogging, so that the microbial concentration, recovery and detection of 1 to 10 CFU/g of Salmonella in poultry products is possible in less than 8 h.

Ready-to-eat (RTE) meat and poultry product samples from the random ALLRTE and risk-based RTE001 sampling projects of the Food Safety and Inspection Service (FSIS) were tested for both Listeria monocytogenes and Salmonella. In the course of analyzing Salmonella data for calendar years 2005 to 2012, it was observed that 8 (17.0%) of 47 positive samples were from pork barbecue. The eight Salmonella-positive samples, from seven establishments in a single state, were from 1,085 pork barbecue samples tested nationwide (0.74% positive) and from 296 samples tested from that one state (2.7% positive). The seven establishments represented 30.4% of 23 federal establishments in that state that had pork barbecue samples tested for Salmonella. A follow-up sample from intensified verification testing at one of the seven establishments also was positive for Salmonella. Upon further examination, contamination appeared to be influenced by regional differences in production methods. Notably, the style of pork barbecue that tested positive for Salmonella used a vinegar- and pepper-based sauce in which the ingredients were mixed without cooking. All the establishments with Salmonella-positive samples followed the practice of first cooking the pork and then adding the barbecue sauce ingredients (vinegar, pepper, other spices, etc.) after cooking (postlethality exposure). In addition to the sauce ingredients, other possible sources of contamination included employee hygiene and food handling practices and cross-contamination from other Salmonella-contaminated products and from commonly used equipment. Based on these findings, the FSIS issued guidelines recommending changes in production methods that would minimize or eliminate pork barbecue as a potential source of foodborne Salmonella infections.

Salmonella-contaminated foods, especially poultry-derived foods (eggs, chicken meat), are the major source of salmonellosis. Not only in the European Union (EU), but also in the United States, Japan, and other countries, has salmonellosis been an issue of concern for food safety control agencies. In 2005, EU regulation 1003/2005 set a target for the control and reduction of five target Salmonella enterica serovars-S. Typhimurium, S. Enteritidis, S. Infantis, S. Hadar, and S. Virchow-in breeding flocks. Thus, a simple biochip for the rapid detection of any of these five Salmonella serovars in poultry products may be required. The objectives of this study were to design S. Virchow-specific primers and to develop a biochip for the simultaneous identification of all or any of these five Salmonella serovars in poultry and poultry products. Experimentally, we designed novel polymerase chain reaction (PCR) primers for the specific detection of S. Virchow, S. Infantis, and S. Hadar. The specificity of all these primers and two known primer sets for S. Typhimurium and S. Enteritidis was then confirmed under the same PCR conditions using 57 target strains and 112 nontarget Salmonella strains as well as 103 non-Salmonella strains. Following multiplex PCR, strains of any of these five Salmonella serovars could be detected by a chromogenic biochip deployed with DNA probes specific to these five Salmonella serovars. In comparison with the multiplex PCR methods, the biochip assay could improve the detection limit of each of the Salmonella serovars from N×10 3 cfu/mL to N×10 2 cfu/mL sample in either the pure culture or the chicken meat samples. With an 8-hour enrichment step, the detection limit could reach up to N×10 0 cfu/mL., (Copyright © 2017. Published by Elsevier B.V.)

One of the leading causes of foodborne illness in poultry products is Salmonella enterica. Salmonella hazards in poultry may be estimated and possible control methods modeled and evaluated through the use of quantitative microbiological risk assessment (QMRA) models and tools. From farm to table, there are many possible routes of Salmonella dissemination and contamination in poultry. From the time chicks are hatched through growth, transportation, processing, storage, preparation, and finally consumption, the product could be contaminated through exposure to different materials and sources. Examination of each step of the process is necessary as well as an examination of the overall picture to create effective countermeasures against contamination and prevent disease. QMRA simulation models can use either point estimates or probability distributions to examine variables such as Salmonella concentrations at retail or at any given point of processing to gain insight on the chance of illness due to Salmonella ingestion. For modeling Salmonella risk in poultry, it is important to look at variables such as Salmonella transfer and cross contamination during processing. QMRA results may be useful for the identification and control of critical sources of Salmonella contamination.

Aims: In this study, a capillary polymerase chain reaction (cPCR) was applied for Salmonella detection from poultry meat., Methods and Results: Salmonella detection limits of the optimized cPCR were determined with DNA templates from the samples of tetrathionate broth (TTB), Rappaport Vassiliadis broth (RVB) and selenite cystine broth (SCB) artificially contaminated with 10-fold dilutions of 6 x 10(8) CFU ml(-1) of pure Salmonella enterica ssp. enterica serovar Enteritidis 64K stock culture. Detection limits of cPCR from TTB, RVB and SCB were found as 6, 6 x 10(1) and 6 x 10(4) CFU ml(-1), respectively. In addition, detection limits of bacteriology were also determined as 6 CFU ml(-1) with TTB and SCB, and 6 x 10(1) CFU ml(-1) with RVB. A total of 200 samples, consisting of 100 chicken and 100 turkey meat samples, were tested with optimized cPCR and bacteriology. Eight and six per cent of the chicken meat samples were found to harbour Salmonella by cPCR and standard bacteriology, respectively. Of six Salmonella isolates, four belonged to serogroup D, two to serogroup B., Conclusions: The TTB cultures of both artificially and naturally contaminated samples were found to be superior to those of RVB and SCB cultures in their cPCR results. This cPCR, utilizing template from 18-h TTB primary enrichment broth culture, takes approximately 40 min in the successful detection of Salmonella from poultry meat., Significance and Impact of the Study: This study shows that cPCR from TTB enrichment culture of poultry meat would enable rapid detection of Salmonella in laboratories with low sample throughput and limited budget.

A study was made in order to improve a new Salmonella identification test (Mucap Test) in which umbelliferone is released, giving a blue fluorescent light under a Wood lamp, after contact with Salmonella colonies. The study concerned 354 colonies, previously isolated from 55 poultry meat samples. Two enrichment media [Tetrathionate Bile Broth (TBB) and Rappaport Vassiliadis (RV)] and two isolation media [Brilliant Green Agar (BGA) and Desoxycholate Agar (DA)] were used, and the results of the test obtained respectively with each association were compared. The sensitivity was consistently good, but the specificity of the test was generally poor. The best association seemed to be RV/DA which gave 85% specificity, against 39% for TBB/BGA, 58% for TBB/DA, and 77% for RV/BGA. The predominant genera responsible for false-positive results were Pseudomonas and Proteus Providencia.

During a Salmonella survey in a large integrated poultry organization it was observed that a significant correlation existed between Salmonella serotypes isolated from the raw feed ingredients and those from finished carcases. A number of serotypes hitherto unrecognized in the organization were detected in the raw feed ingredients, and were later recognized in live birds and carcases from the processing plant. It appears that a significant reduction in carcase contamination rate could be achieved by minimizing Salmonella in the meal and grain constituents of poultry feed.

Between the period of August 1973 and May 1974, 553 roasting chickens, soup chickens, ducks, and geese from seven different countries were examined for the presence of Salmonella. In 284 (= 51,4%) specimens 23 various Salmonella serotypes were discovered. Out of 475 Salmonella isolates 244 (= 51,4%) were resistant to streptomycin, the sulfonamide complex or their combination whereas 195 (= 41,0%) were sensitive to all eight tested antibiotics. Of greater importance for nutritive and therapeutic application of antibiotics is, however, the resistance of 36 (= 7,6%) Salmonella strains to tetracyclines, ampicillin and kanamycin, 28 (= 5,9%) of the salmonellae showing resistance exclusively to tetracyclines. The water tested from 10 thawed specimens 2 of which contained diphosphates, produced dubious results with the general inhibitor test. Regarding the bacterial yield, both the selenite and tetrathionate enrichments were of equal value. Nevertheless with each individual enrichment the isolated partial amount of the entire collection of positive samples was not identical so that the highest yield of Salmonella was obtained from a combination of both methods. Incubation of the selenite enrichment at a maximum of 43 degrees C definitely produced a higher percentage than at 37 degrees C. A selenite enrichment proved to be superior to that of tetrathionate for the isolation of Salmonella serotypes which rarely occur in fowl. The excellent selectivity of the Brilliant-green Phenol-red Lactose Sucrose Agar, as repeatedly described in the literature, is also confirmed by these tests.

A collaborative study was performed in 13 laboratories to validate an enzyme immunoassay (EIA) procedure for rapid detection of Salmonella in foods. The EIA was compared with the standard culture procedure for detection of Salmonella in 6 food types: ground black pepper, soy flour, dried whole eggs, milk chocolate, nonfat dry milk, and raw deboned turkey. Uninoculated and inoculated samples were included in each food group analyzed. There was no significant difference in the proportion of samples positive by the EIA and culture procedures at the 5% level for any of the 6 foods. The enzyme immunoassay screening method has been adopted official first action as a rapid screening method for detection of Salmonella.

A collaborative study was performed to validate the performance of the 1-2 TEST for detection of motile salmonellae in foods. Detection is based on observation of an immobilized band of cells. Twenty-three laboratories participated in the study. The 1-2 TEST (immunodiffusion test) was compared with the standard culture procedure (BAM/AOAC; FDA Bacteriological Analytical Manual) for detection of Salmonella in 6 food types: ground black pepper, soy flour, dried whole egg, milk chocolate, nonfat dry milk, and raw deboned turkey. Uninoculated and inoculated samples were included in each food group analyzed. After the tests on the 6 foods were completed, analysis of the data for turkey and soy flour showed that certain collaborators obtained data inconsistent with the data from the majority of collaborators. No specific method deviations to account for the inconsistencies were reported by those collaborators, so the collaborative testing of these 2 foods was repeated. Analysis of data for pepper, chocolate, nonfat dry milk, dried whole egg, and the second set of soy flour and turkey indicated 96.1% agreement between the BAM/AOAC and immunodiffusion test methods. The false negative rates for the immunodiffusion test and BAM/AOAC methods were 3.6 and 1.7%, respectively. There was no significant difference in the productivity of the immunodiffusion test and BAM/AOAC method at the 5% level for any of the 6 foods. The immunodiffusion screening method has been approved official first action for detection of motile Salmonella in foods.

Dulcitol-selenite enrichment medium in a motility flask was used for the detection of Salmonella in food. A drop in pH of the dulcitol-selenite enrichment motility broth indicated the presence of Salmonella; this phenomenon was confirmed by fluorescent-antibody staining. A complete correlation was found between fluorescent-antibody staining and recovery on Brilliant Green agar. Testing of 332 samples of 8 different kinds of foods and feeds indicated no significant difference in sensitivity between the new technique and a conventional Salmonella detection technique. The new technique permitted detection of even small numbers of Salmonella in 1 to 2 days.

Bacteriological examination of 1,427 samples from a poultry-processing plant over a 2-year period yielded 202 (14.2%) cultures positive for salmonellae. The results indicate that contamination is reduced by washing procedures within the plant but that recontamination of the carcasses occurred in at least two different stages of processing, i.e., during evisceration and chilling. There was evidence of spread of salmonellae from flock to flock during the serial processing of flocks, but the spread was usually not extensive. The serotypes of salmonellae isolated in this study were similar to those of chicken origin reported from other areas of the country.

Brilliant Green (BG) agar and Hektoen enteric (HE) agar media were compared for their efficiency in isolating salmonellae from various food products. Of the 11,226 food specimens examined, 1,662 (or 14.9%) yielded salmonellae. Of this number, 1,475 (88.7%) were recovered from BG agar and 1,315 (79.1%) were recovered from HE agar media. The results indicate that BG agar is more effective in isolating salmonellae from food products. A smaller subsidiary study showed HE agar to be more selective than BG agar. Four hundred ten specimens yielded 92 nonlactose-fermenting isolants other than salmonellae on BG agar and only 11 such isolants on HE agar.

Salmonella spp. is one of the most important foodborne pathogens worldwide. Given the fact that poultry and poultry products are the main source of human infection, Salmonella control in these farms is of utmost importance. To better control this pathogen in farms, boot swabs are used to sample farm environments but the analysis of these swabs is mainly based on culture-dependent methods. In the present study, a novel loop-mediated isothermal amplification (LAMP) method was developed for the rapid screening of Salmonella spp. in boot swab samples from broiler flock environments. Four different DNA extraction protocols were evaluated in depth, including a simple thermal lysis, a chelex-based protocol and two thermal lysis protocols followed by the purification of magnetic beads made of silica ("glass milk") in order to determine the most suitable alternative for potential on-site, farm analyses. The methodology evaluation included a blind interlaboratory assay and as a proof-of-concept, a naked-eye colorimetric assay was also included. Following the final methodology, it was possible to reach an LoD50 of 1.8 CFU/25 g of the samples, with a high relative sensitivity (95.7%), specificity (100%) and accuracy (96.6%) along with Cohen's kappa of concordance with respect to the ISO standard 6579-1:2017 of 0.9, with an RLOD of 1.3. In addition to this, due to the relevance of certain serotypes with the genus Salmonella spp., a serotype LAMP panel for the specific identification of S. Typhimurium, S. Enteritidis, S. Infantis, S. Hadar and S. Virchow was also developed. Even though some degree of cross-reactivity among the primers developed was observed, all the serotypes could be accurately identified based on their melt curve analysis profile. Taken together, in the present study, a rapid Salmonella spp. screening method, suitable for farm applications, was developed, along with a serotyping panel that could be used in a laboratory setup for the identification of the most relevant serotypes of the genus, taking advantage of real-time amplification followed by melt curve analysis. [ABSTRACT FROM AUTHOR]

Various Salmonella serotypes have caused numerous foodborne outbreaks associated with food vehicles in different categories. This study provides evidence on the occurrence and inter-relations between Salmonella serotypes and the number of deaths mediated by the number of illnesses and hospitalizations. Confirmed foodborne outbreaks of Salmonella serotypes (n = 2868) that occurred between 1998 and 2021 were obtained from the Centers for Disease Control and Prevention National Outbreak Reporting System. Causal mediation analysis was performed based on 500 bootstrap samples. The serotypes and the Interagency Food Safety Analytics Collaboration (IFSAC) food categories as confounding effects were considered as categorical variables. A total of 106 single Salmonella serotypes were associated with foodborne outbreaks. Foodborne outbreaks caused by Salmonella serotypes resulted in 81,996 illnesses, 11,018 hospitalizations, and 115 deaths between 1998 and 2021 in the United States. The serotypes Enteritidis (815 outbreaks, 28.42%), Typhimurium (359 outbreaks, 12.52%), and Newport (220 outbreaks, 7.67%) accounted for almost half of Salmonella-linked outbreaks. Poultry products, "chickens", "eggs", and "turkey", were the leading IFSAC food categories, accounting for 14.02% of total outbreaks and 10.44% of total deaths. Certain serotypes had a significant effect on illness, hospitalization, and death counts. Two serotypes, Heidelberg and Saintpaul, and "fruits" as the food vehicle in IFSAC categories had a significant direct effect on the number of illnesses, hospitalizations, and deaths as outcomes of Salmonella outbreaks (p ≤ 0.05). There was strong evidence that illness and hospitalization counts played a key role in the pathway from serotype to death counts on foodborne outbreaks caused by Salmonella based on causal mediation analysis. The findings of this study can help outbreak investigations and lead to prevention and control measures by providing insightful information about the frequencies of Salmonella serotypes and the associated food vehicles causing foodborne diseases. [ABSTRACT FROM AUTHOR]

Background: Salmonella is an important zoonotic pathogen, of which poultry products are important reservoirs. This study analyzed the prevalence, antimicrobial resistance, and characterization of Salmonella from broiler and laying hen sources in China. Methods: A total of 138 (12.27%) strains of Salmonella were isolated from 1125 samples from broiler slaughterhouses (20.66%, 44/213), broiler farms (18.21%, 55/302), and laying hen farms (6.39%, 39/610). Multiplex PCR was used to identify the serotypes. Antibiotic susceptibility testing to a set of 21 antibiotics was performed and all strains were screened by PCR for 24 selected antimicrobial resistance genes (ARGs). In addition, 24 strains of Salmonella were screened out by whole-genome sequencing together with 65 released Salmonella genomes to evaluate phylogenetic characteristics, multilocus sequence typing (MLST), and plasmid carriage percentages. Results: A total of 11 different serotypes were identified, with the dominance of S. Enteritidis (43/138, 31.16%), S. Newport (30/138, 21.74%), and S. Indiana (19/138, 13.77%). The results showed that S. Enteritidis (34.34%, 34/99) and S. Newport (51.28%, 20/39) were the dominant serotypes of isolates from broilers and laying hens, respectively. The 138 isolates showed the highest resistance to sulfisoxazole (SXZ, 100%), nalidixic acid (NAL, 54.35%), tetracycline (TET, 47.83%), streptomycin (STR, 39.86%), ampicillin (AMP, 39.13%), and chloramphenicol (CHL, 30.43%), while all the strains were sensitive to both tigacycline (TIG) and colistin (COL). A total of 45.65% (63/138) of the isolates were multidrug-resistant (MDR) strains, and most of them (61/63, 96.83%) were from broiler sources. The results of PCR assays revealed that 63.77% of the isolates were carrying the quinolone resistance gene qnrD, followed by gyrB (58.70%) and the trimethoprim resistance gene dfrA12 (52.17%). Moreover, a total of thirty-four ARGs, eighty-nine virulence genes, and eight plasmid replicons were detected in the twenty-four screened Salmonella strains, among which S. Indiana was detected to carry the most ARGs and the fewest plasmid replicons and virulence genes compared to the other serotypes. Conclusions: This study revealed a high percentage of multidrug-resistant Salmonella from poultry sources, stressing the importance of continuous monitoring of Salmonella serotypes and antimicrobial resistance in the poultry chain, and emergency strategies should be implemented to address this problem. [ABSTRACT FROM AUTHOR]

Whole genome sequencing is replacing traditional laboratory surveillance methods as the primary tool to track and characterize clusters and outbreaks of the foodborne and zoonotic pathogen Salmonella enterica (S. enterica). In this study, 438 S. enterica isolates representing 35 serovars and 13 broad vehicle categories from one hundred epidemiologically confirmed outbreaks were evaluated for genetic variation to develop epidemiologically relevant interpretation guidelines for Salmonella disease cluster detection. The Illumina sequences were analyzed by core genome multi-locus sequence typing (cgMLST) and screened for antimicrobial resistance (AR) determinants and plasmids. Ninety-three of the one hundred outbreaks exhibited a close allele range (less than 10 allele differences with a subset closer than 5). The remaining seven outbreaks showed increased variation, of which three were considered polyclonal. A total of 16 and 28 outbreaks, respectively, showed variations in the AR and plasmid profiles. The serovars Newport and I 4,[5],12:i:-, as well as the zoonotic and poultry product vehicles, were overrepresented among the outbreaks, showing increased variation. A close allele range in cgMLST profiles can be considered a reliable proxy for epidemiological relatedness for the vast majority of S. enterica outbreak investigations. Variations associated with mobile elements happen relatively frequently during outbreaks and could be reflective of changing selective pressures. [ABSTRACT FROM AUTHOR]

Salmonella is a common cause of human foodborne illness, which is frequently associated with consumption of contaminated or undercooked poultry meat. Serotype Infantis is among the most common serotypes isolated from poultry meat products globally. Isolates of serotype Infantis carrying the pESI plasmid, the most dominant strain of Infantis, have been shown to exhibit oxidizer tolerance. Therefore, 16 strains of Salmonella with and without pESI carriage were investigated for susceptibility to biocide chemical processing aids approved for use in US poultry meat processing: peracetic acid (PAA), cetylpyridinium chloride (CPC), calcium hypochlorite, and sodium hypochlorite. Strains were exposed for 15 s to simulate spray application and 90 min to simulate application in an immersion chiller. All strains tested were susceptible to all concentrations of PAA, CPC, and sodium hypochlorite when applied for 90 min. When CPC, calcium hypochlorite, and sodium hypochlorite were applied for 15 s to simulate spray time, strains responded similarly to each other. However, strains responded variably to exposure to PAA. The variation was not statistically significant and appears unrelated to pESI carriage. Results highlight the necessity of testing biocide susceptibility in the presence of organic material and in relevant in situ applications. [ABSTRACT FROM AUTHOR]

The high Salmonella and Listeria monocytogenes risk in poultry products reinforces the urgent need for new technologies with high antimicrobial effects. In that sense, a combined technology consisting of encapsulated extra virgin olive oil (EVOO) during chicken nugget breading combined with infrared processing was hereby studied at three levels (experiments). The high in vitro EVOO antimicrobial activity (up to 74%), which was 1.2-fold higher against L. monocytogenes than Salmonella, was enhanced after encapsulation (α-cyclodextrin) by 1.5–2.0 and 1.2–1.6-fold, respectively (experiment 1). Oil-free processing (infrared and convection ovens) combined with encapsulated EVOO (2.5 and 1.6% EVOO doses) even enhanced the high in vitro antimicrobial activity of encapsulated EVOO (experiment 2). In the in vivo study (experiment 3), infrared (180 °C, 6.4 min) + convection air (120 °C, 10 min) processing combined with encapsulated EVOO (1.6 and 2.5%) within chicken nugget breading of the chicken nuggets achieved in vivo antimicrobial reductions of 60 and 80% against Salmonella and L. monocytogenes, respectively. In conclusion, this new technology including encapsulated EVOO (1.6–2.5%) within the breading of chicken nuggets and innovative oil-free processing may ensure the food safety of these poultry products very susceptible to the incidence of Salmonella and L. monocytogenes. [ABSTRACT FROM AUTHOR]

Poultry and poultry products are the common sources of Salmonella,which is one of the serious food-borne bacterial diseases in humans. Little is known about the status of Salmonella and their antimicrobial susceptibility in poultry farms in Addis Ababa. This study was conducted to estimate the prevalence and antimicrobial susceptibility of Salmonella isolates and to investigate possible risk factors for the occurrence of Salmonella in poultry farms in Addis Ababa. We recruited 58 poultry farms, from which 471 poultry-related samples and 44 stool samples from in-contact humans were collected. The isolates were tested for their susceptibility to 11 antimicrobials using the Kirby–Bauer disk diffusion assay. The farm-level prevalence of Salmonella was 36.2% and the sample-level prevalence was 6.4% for samples taken from poultry farms and 4.5% in human stool samples who have contact with poultry. On-farm waste disposal practices and chicken being purchased from different multiplication farms were significantly associated with Salmonella positivity of the farms (p < 0.05). Eleven (34.4%) Salmonella isolates were resistant to streptomycin, and nine (28.1%) were resistant to tetracycline. Thirteen (40.6%) Salmonella isolates were resistant to two or more antimicrobials tested in this study, whereas resistance to 3 or more antimicrobials was detected in seven (21.9%) isolates. In conclusion, a high prevalence of Salmonella and a high rate of resistance to multiple antimicrobials were detected in poultry farms in Addis Ababa. Hence, implementation of strong biosecurity measures and rational use of antimicrobials are recommended. [ABSTRACT FROM AUTHOR]

The application of live attenuated Salmonella Typhimurium vaccines has significantly helped control Salmonella in poultry products. Because the U.S. Department of Agriculture–Food Safety Inspection Service (USDA-FSIS) scores all Salmonella as positive, regardless of serovar, attenuated vaccine strains that are identified at processing contribute negatively toward Salmonella performance standards. This study was designed to determine the incidence of a live attenuated Salmonella serovar Typhimurium vaccine identified in broiler products by FSIS and to develop a PCR assay for screening of isolates. Salmonella Typhimurium short-read sequences from broiler samples uploaded to the National Center for Biotechnology Information (NCBI) Pathogen Detection database by the USDA-FSIS from 2016 to 2022 were downloaded and assembled. These were analyzed using the Basic Local Alignment Search Tool (BLAST) with a sequence unique to field strains, followed by a sequence unique to the vaccine strain. The PCR assays were developed against field and vaccine strains by targeting transposition events in the crp and cya genes and validated by screening Salmonella serovar Typhimurium isolates. Between 2016 and 2022, 1708 Salmonella Typhimurium isolates of chicken origin were found in the NCBI Pathogen Detection database, corresponding to 7.99% of all Salmonella identified. Of these, 104 (5.97%) were identified as the vaccine strain. The PCR assay differentiated field strains from the vaccine strain when applied to isolates and was also able to detect the vaccine strain from DNA isolated from mixed serovar overnight Salmonella enrichment cultures. Live attenuated Salmonella vaccines are a critical preharvest tool for Salmonella control and are widely used in industry. With forthcoming regulations that will likely focus on Salmonella Typhimurium, along with other serovars, there is a need to distinguish between isolates belonging to the vaccine strain and those that are responsible for causing human illness. Detección in silico y por PCR de una cepa vacunal viva atenuada de Salmonella Typhimurium. La aplicación de vacunas vivas atenuadas contra Salmonella Typhimurium ha ayudado significativamente a controlar Salmonella en productos avícolas. Debido a que el Servicio de Inspección de Seguridad Alimentaria del Departamento de Agricultura de los Estados Unidos. (USDA-FSIS) califica todas las Salmonella como positivas, independientemente del serovar. Las cepas atenuadas de la vacuna que se identifican en el procesamiento contribuyen negativamente a los estándares de desempeño de Salmonella. Este estudio fue diseñado para determinar la incidencia de una vacuna viva atenuada de Salmonella serovar Typhimurium identificada en productos de pollo de engorde por el FSIS y para desarrollar un ensayo de PCR para la detección de aislados. Se recolectaron y ensamblaron secuencias de lectura corta de Salmonella Typhimurium de muestras de pollos de engorde introducidas en la plataforma de detección de patógenos del Centro Nacional de Información Biotecnológica (NCBI) por el USDA-FSIS entre los años 2016 al 2022. Estos se analizaron utilizando la herramienta de búsqueda de alineación local básica con una secuencia exclusiva para las cepas de campo, seguida de una secuencia exclusiva para la cepa vacunal. Los ensayos de PCR se desarrollaron contra cepas de campo y vacunales centrándose en eventos de transposición en los genes crp y cya y se validaron mediante la detección de aislados de Salmonella serovar Typhimurium. Entre 2016 y 2022, se encontraron 1708 aislados de Salmonella Typhimurium de origen avícola en el sistema de detección de patógenos del NCBI, lo que corresponde al 7.99 % de todas las Salmonellas identificadas. De ellas, 104 (5.97%) fueron identificadas como cepa vacunal. El ensayo de PCR diferenció las cepas de campo de la cepa de la vacuna cuando se aplicó a los aislados y también fue capaz de detectar la cepa de la vacuna a partir del ADN aislado de cultivos de enriquecimiento por toda la noche de Salmonella con serovares mixtos. Las vacunas vivas atenuadas contra Salmonella son una herramienta fundamental para el control de Salmonella y se utilizan ampliamente en la industria. Con las próximas regulaciones que probablemente se centrarán en Salmonella Typhimurium, junto con otros serovares, es necesario distinguir entre los aislados que pertenecen a la cepa vacunal y los que son responsables de causar enfermedades humanas. [ABSTRACT FROM AUTHOR]

Retrospective review is a key to designing effective food safety measures. Despite the reported reduction of Salmonella prevalence in poultry products, there has not been a concomitant reduction of the overall incidence of Salmonella illnesses reported to the US Foodborne Diseases Active Surveillance Network (FoodNet) since 1996. However, there have been significant annual trends among Salmonella serotypes. This analysis examines trends in the reported incidence of illness due to poultry‐ and nonpoultry associated Salmonella serotypes. Overall, the findings indicate declining trends in illness due to the poultry‐associated serotypes and increasing trends in illness due to Salmonella serotypes not associated with poultry. [ABSTRACT FROM AUTHOR]

Human foodborne outbreaks with antibiotic-resistant Salmonella enterica associated with contaminated poultry products have recently involved serogroup C serovars Infantis and Hadar. The current study evaluated a commercially available Salmonella vaccine for cross-protection against Infantis and Hadar serovars in turkeys. The live, attenuated S. Typhimurium (serogroup B) vaccine significantly reduced colonization of intestinal tissues (cecum, cecal tonsils, and cloaca) by serovars Infantis (C1) and Hadar (C2) and significantly limited systemic dissemination to the spleen. S. Infantis, but not S. Hadar, disseminated to bone marrow in non-vaccinated turkeys, but vaccination prevented S. Infantis dissemination to the bone marrow. The S. Infantis challenge strain contained the pESI megaplasmid, and virulence mechanism(s) residing on this plasmid may support dissemination and/or colonization of systemic niches such as myeloid tissue. Collectively, the data indicate that vaccinating turkeys with the serogroup B S. Typhimurium vaccine limited intestinal colonization and systemic dissemination by serogroup C serovars Infantis and Hadar. [ABSTRACT FROM AUTHOR]

Successful detection of bacterial pathogens in food can be challenging due to the physical and compositional complexity of the matrix. Different mechanical/physical and chemical methods have been developed to separate microorganisms from food matrices to facilitate detection. The present study benchmarked a commercial tissue digestion system that applies both chemical and physical methods to separate microorganisms from tissues against stomaching, a standard process currently utilized by commercial and regulatory food safety laboratories. The impacts of the treatments on the physical properties of the food matrix were characterized along with the compatibility of the methods with downstream microbiological and molecular detection assays. The results indicate the tissue digestion system can significantly reduce the average particle size of the chicken sample relative to processing via a stomacher (P < 0.001) without adversely affecting either real-time PCR (qPCR) or plate counting assays, which are typically used to detect Salmonella. Furthermore, inoculated chicken treated with the GentleMACS resulted in a significant increase (P < 0.003) in the qPCR's detection capabilities relative to stomached controls. Cohen kappa (κ) coefficient and McNemar's test indicate the plating assays and PCR results agree with measurements obtained via the 3 M Molecular Detection System as defined in the MLG standard (κ > 0.62; P > 0.08). Collectively, the results demonstrate that the technique enables detection of pathogens in meat at lower levels of contamination using current industry standard technologies. [ABSTRACT FROM AUTHOR]

Salmonella is a major foodborne pathogen and a leading cause of gastroenteritis in humans and animals. Salmonella is highly pathogenic and encompasses more than 2600 characterized serovars. The transmission of Salmonella to humans occurs through the farm-to-fork continuum and is commonly linked to the consumption of animal-derived food products. Among these sources, poultry and poultry products are primary contributors, followed by beef, pork, fish, and non-animal-derived food such as fruits and vegetables. While antibiotics constitute the primary treatment for salmonellosis, the emergence of antibiotic resistance and the rise of multidrug-resistant (MDR) Salmonella strains have highlighted the urgency of developing antibiotic alternatives. Effective infection management necessitates a comprehensive understanding of the pathogen's epidemiology and transmission dynamics. Therefore, this comprehensive review focuses on the epidemiology, sources of infection, risk factors, transmission dynamics, and the host range of Salmonella serotypes. This review also investigates the disease characteristics observed in both humans and animals, antibiotic resistance, pathogenesis, and potential strategies for treatment and control of salmonellosis, emphasizing the most recent antibiotic-alternative approaches for infection control. [ABSTRACT FROM AUTHOR]

Salmonellosis is one of the most important foodborne diseases worldwide, including the European Union. Despite the One Health approach measures for risk assessment and risk management implemented by the European Union, the occurrence of disease and disease outbreaks remains high (e.g. 694 outbreaks were reported in 2020), highlighting the need of new assessment methods. Herein we applied machine learning using the random forests method to evaluate and identify key points regarding the occurrence of Salmonella sp. along the Spanish food chain during 2015–2020, using data provided by the Spanish Agency for Food Safety and Nutrition. We compared the role of the three categorical variables [product (20 categories), region (18 categories) and stage (11 categories)]. Salmonella presence was influenced by the three explanatory variables considered: first by product, followed by region and stage. The most determinant product for Salmonella probability was 'meat', while the most important stage was 'slaughterhouse'. Specifically, the highest values were found in pig and poultry meats. In these products, the Salmonella probability was high at the early and final stages of the food chain, although not at intermediate stages. The presence of Salmonella in the final stages (retail) of the food chain is of concern, as it can cause human cases of salmonellosis, including outbreaks. This study demonstrates the utility of the random forest method to identify key points and evaluate the control efforts. We recommend improving the surveillance and control measures, especially in the product and stages pointed out by our analysis, and enhancing the data collection harmonization among the different autonomous communities. [ABSTRACT FROM AUTHOR]

Simple Summary: Foodborne salmonellosis remains one of the top zoonotic diseases affecting public health worldwide, and its incidence has remained stable in the last years in the European Union (EU) triggering questions on the usefulness of currently available measures to prevent its occurrence. A main focus of Salmonella national control programs is monitoring the presence of the bacteria in animal reservoirs, especially in poultry, and for this reason, thousands of samples are collected every year in poultry farms in EU countries, but the importance of certain factors in the probability of detecting Salmonella remains poorly understood. A thorough analysis conducted on data collected in all laying hen flocks sampled in Spain in 2015–2020 revealed that even though the presence of Salmonella was rare (<3.5% of positive sampling events), when samples were collected in certain months (fall–winter) and housing systems (caged flocks) and by competent authorities (as opposed to food business operators), the probability of detecting Salmonella increased significantly. These results demonstrate that the sensitivity of the sampling strategy may be influenced by how and when samples are collected and that certain flocks may be at an increased risk of infection. Trends in Salmonella human infections are assumed to be related to the distribution of the pathogen in the animal reservoir/food products, and cases in humans are most often linked to poultry and poultry products (eggs, meat). Therefore, ongoing Salmonella national control programs (NCPs) in European Union Member States have the objective of monitoring and reducing its prevalence in commercial poultry flocks. Results from NCPs have shown certain factors (housing systems, season of sampling and if sampling is conducted by food business operators (FBOps) or competent authorities (CAs), among others) can influence detection rates, but associations are often not consistent. Here, we analyzed data from the Spanish NCP on 7216 laying hen flocks subjected to 36,193 sampling events over a six-year period to characterize its performance and identify variables influencing detection rates. Overall, 1205 sampling events were positive for Salmonella spp. (any serovar) and 132 for S. Enteritidis-S. Typhimurium/monophasic. Bayesian multivariable models adjusting for multiple covariates concluded that sampling events later in the year, in caged flocks with older animals and conducted by CAs had increased odds of positivity for Salmonella spp., revealing aspects linked with a differential estimation of Salmonella levels in laying hen flocks. [ABSTRACT FROM AUTHOR]

Non typhoidal Salmonella typhimurium is a major food borne pathogen associated with the intestinal tract of food-producing animals. Salmonella is frequently detected in poultry meat; thus, contaminated poultry products are a significant source of human salmonellosis. The present study was conducted to study the dynamics of antibiotic resistance patterns among non typhoidal Salmonella isolated from chicken cecum in Bhopal and to select an effective antimicrobial agent for controlling Salmonella in poultry birds. A total of 80 Salmonella strains isolated from cecum belonging to Typhimurium serovar were screened for their antimicrobial resistance pattern using20 antimicrobial agents falling under 8 different antibiotic classes. The antibiogram testing revealed differential multidrug resistance among Salmonella isolates in poultry samples. All the isolates were resistant to Tobramycin, Moxifloxacin, Sparfloxacin, Co-Trimoxazole, Nalidixic acid, Augmentin, Kanamycin, Gentamicin, Amikacin and Ticarcillin, indicating high level of resistance among the bacteria associated with poultry. Conclusively, finding of this study provides new information regarding the prevalence and antimicrobial resistance and Salmonella serovar diversity in retail markets of Bhopal city. The detection of zoonotic potential MDR Salmonella typhimurium in poultry presents a major threat to the poultry industry and public health. Thus, care must be taken in the use of antibiotics in farm animals to reduce the selection of multidrug resistant bacterial strains. [ABSTRACT FROM AUTHOR]

Salmonella spp. is considered one of the most important causes of food-borne illness globally. Poultry and its products are usually incriminated in its spread. Treatment with antibiotics is the first choice to deal with such cases; however, multi-drug resistance and biofilm formation have been recorded in animals and humans. This study aimed to detect the antibiotic profile of isolated traits from different sources and to find innovative alternatives, such as MOFs. A total of 350 samples were collected from randomly selected retailed poultry shops in Beni-Suef Province, Egypt. Their antimicrobial susceptibility against eight different antibiotics was tested, and multi-drug resistance was found in most of them. Surprisingly, promising results toward MOF were detected. Cu/Ni/Co-MOF (MOF3) showed superior antibacterial efficiency to Cu/Ni-MOF (MOF2) and Cu-MOF (MOF1) at p value ≤ 0.01. These findings highlight the tendency of Salmonella spp. to develop MDR to most of the antibiotics used in the field and the need to find new alternatives to overcome it, as well as confirming the ability of the environment to act as a source of human and animal affection. [ABSTRACT FROM AUTHOR]

Salmonella is one of the leading causes of foodborne illnesses worldwide, with poultry products being a major source of contamination. Thus, the detection of salmonella in commercial poultry products is crucial to minimize the effects on public health. Electrochemical sensors are promising tools for bacteria detection due to their sensitivity, simplicity, and potential for on-site analysis. In this work, a three-dimensional (3D) printed electrochemical immunosensor for the determination of Salmonella typhimurium in fresh chicken through a sandwich immunoassay employing biotinylated anti-S. typhimurium antibody followed by streptavidin labeled with Cd/Se ZnS quantum dots (QDs) is presented. The device features three carbon-black polylactic acid electrodes and a holder, and the quantification of S. typhimurium is performed by anodic stripping voltametric (ASV) determination of the Cd(II) released after acidic dissolution of the QDs. To enhance sensitivity, an electroplated bismuth film was deposited on the working electrode, achieving a detection limit of 5 cfu/mL in a total assay time of 25 min, whereas 5 h of sample pre-enrichment was required for the detection of 1 cfu/25 mL of chicken rinse and chicken broth. The method is accurate, with %recovery values ranging from 93.3 to 113% in fresh chicken samples, and repeatable with intra- and inter- assay coefficient of variations <2 and 5%, respectively, indicating the suitability of the proposed immunosensor for the detection of S. typhimurium at the point-of-need. [ABSTRACT FROM AUTHOR]

Controlling Salmonella in poultry processing continues to be important to processors and consumers. Cetylpyridinium chloride (CPC) has proven to be effective in vitro in controlling Salmonella. This study evaluated the recovery of Salmonella after overnight storage in 4°C filter‐sterilized carcass rinsate containing CPC from 0.44 to 909 ppm (μg/mL). Ten Salmonella serotypes (18 strains), of which 6 serotypes are commonly isolated from poultry products, were grown in Bacto‐Tryptic Soy Broth overnight at 37°C. Serial dilutions of a CPC/propylene glycol solution were prepared in 24‐well tissue culture plates containing filter‐sterilized carcass rinsate. Approximately 107 cfu/mL of each Salmonella serotype was added to the appropriate wells. Inoculated plates were stored overnight at 4°C. After storage, triplicate plates of brilliant green agar with sulfapyridine (BGS) were surface inoculated with 10 μL of the contents for each well, streaked for isolation, and incubated at 37°C for 24 h. Three replications were conducted. The presence of typical colonies on BGS plates was recorded as growth and verified through biochemical and serological testing. Of the serotypes chosen, Salmonella Kentucky, Dublin, and Enteritidis were the least resistant to CPC with a median minimum inhibitory concentration (MIC) of 14.22 μg/mL (range from 3.55 to 56.88 μg/mL); S. Typhimurium demonstrated a median MIC of 114.00 μg/mL (range from 28.44 to 114.00 μg/mL). Residual CPC potentially remaining attached to a carcass or in the weep after processing could potentially alter which Salmonella serotype is recovered from a carcass rinse due to different growth patterns during regulatory testing, with a potential for more virulent strains not to be recovered. [ABSTRACT FROM AUTHOR]