Detection and Characterization of Salmonella Serotypes in the Production Chain of Two Pig Farms in Buenos Aires Province, Argentina

Outbreak of multidrug-resistant Salmonella infections in people linked to pig ear pet treats, United States, 2015-2019: results of a multistate investigation

Background

International distribution of contaminated foods can be a source of Salmonella infections in people and can contribute to the spread of antimicrobial-resistant bacteria across countries. We report an investigation led by the United States Centers for Disease Control and Prevention, the Food and Drug Administration (FDA), and state governmental officials into a multistate outbreak of salmonellosis linked to pig ear pet treats.

Methods

Pig ear treats and companion dogs were tested for Salmonella by state officials and the FDA. Products were traced back to the country of origin when possible. Cases were defined as outbreak illnesses in people associated with one of seven Salmonella serotypes genetically related to samples from pig ear pet treats, with isolation dates from June 2015 to September 2019. Whole genome sequencing (WGS) of isolates was used to predict antimicrobial resistance.

Findings

The outbreak included 154 human cases in 34 states. Of these, 107 of 122 (88%) patients reported dog contact, and 65 of 97 (67%) reported contact with pig ear pet treats. Salmonella was isolated from 137 pig ear treats, including some imported from Argentina, Brazil, and Colombia, and from four dogs. WGS predicted 77% (105/137) of human and 43% (58/135) of pig ear treat isolates were resistant to ≥3 antimicrobial classes.

Interpretation

This was the first documented United States multistate outbreak of Salmonella infections linked to pig ear pet treats. This multidrug-resistant outbreak highlights the interconnectedness of human health and companion animal ownership and the need for zoonotic pathogen surveillance to prevent human illness resulting from internationally transported pet food products.

Funding

Animal Feed Regulatory Program Standards award. Animal and product testing conducted by FDA Vet-LIRN was funded by Vet-LIRN infrastructure grants (PAR-22-063).

Genomic and Phenotypic Analysis of Salmonella enterica Bacteriophages Identifies Two Novel Phage Species

Bacteriophages (phages) are potential alternatives to chemical antimicrobials against pathogens of public health significance. Understanding the diversity and host specificity of phages is important for developing effective phage biocontrol approaches. Here, we assessed the host range, morphology, and genetic diversity of eight Salmonella enterica phages isolated from a wastewater treatment plant. The host range analysis revealed that six out of eight phages lysed more than 81% of the 43 Salmonella enterica isolates tested. The genomic sequences of all phages were determined. Whole-genome sequencing (WGS) data revealed that phage genome sizes ranged from 41 to 114 kb, with GC contents between 39.9 and 50.0%. Two of the phages SB13 and SB28 represent new species, Epseptimavirus SB13 and genera Macdonaldcampvirus, respectively, as designated by the International Committee for the Taxonomy of Viruses (ICTV) using genome-based taxonomic classification. One phage (SB18) belonged to the Myoviridae morphotype while the remaining phages belonged to the Siphoviridae morphotype. The gene content analyses showed that none of the phages possessed virulence, toxin, antibiotic resistance, type I-VI toxin-antitoxin modules, or lysogeny genes. Three (SB3, SB15, and SB18) out of the eight phages possessed tailspike proteins. Whole-genome-based phylogeny of the eight phages with their 113 homologs revealed three clusters A, B, and C and seven subclusters (A1, A2, A3, B1, B2, C1, and C2). While cluster C1 phages were predominantly isolated from animal sources, cluster B contained phages from both wastewater and animal sources. The broad host range of these phages highlights their potential use for controlling the presence of S. enterica in foods.

Comprehensive evaluation of abattoirs with no Hazard Analysis Critical Control Point plan in Tucumán, Argentina

This work focused on the comprehensive study of two provincial transit abattoirs in Tucumán, Argentina, with no Hazard Analysis Critical Control Point (HACCP) plan. Visits (n=20) were conducted between 2016 and 2018 during the operational and post-operational processes. Risk was estimated and the bacteriological analysis of carcass and environmental samples was performed. Risk estimation showed the predominance of high risk in both abattoirs. The main deviations from the HACCP plan were: deficient building conditions, deficient workflow, lack of sectorization of changing rooms and bathrooms, lack of implementation of Standardized Sanitary Operational Procedures, and no food safety training of workers. The counts of indicator microorganisms from both abattoirs were not significant. Salmonella spp. was isolated from 7.5% carcass and 7.3% environmental samples. The Salmonella serovars identified were Cerro, Corvallis, Havana and Agona. Shiga toxin (stx) genes were detected in 24.4% carcass and 30.9% environmental samples. The isolates were characterized as Escherichia coli O8:H7/stx₁, O116:H49/stx₂ and O136:H40/stx₂. Based on these results, it would be possible to implement an improvement plan in Tucumán abattoirs together with the local health authorities. Still, the need to work jointly with the sanitary authority in search of a unique sanitary standard for Argentina remains unaddressed.

Antimicrobial resistance dissemination associated with intensive animal production practices in Argentina: A systematic review and meta-analysis

Abuse and misuse of antimicrobial agents has accelerated the spread of antimicrobial-resistant bacteria. The association between antimicrobial-resistant infections in humans and antimicrobial use in agriculture is complex, but well-documented. This study provides a systematic review and meta-analysis of the dissemination of antimicrobial resistance (AMR) to antimicrobials defined as critically important by the WHO, in swine, chicken, and cattle from intensive and extensive production systems in Argentina. We conducted searches in electronic databases (MEDLINE-PubMed, Web of Science, SciELO, the National System of Digital Repositories from Argentina) as well as in the gray literature. Inclusion criteria were epidemiological studies on AMR in the main food-transmitted bacteria, Salmonella spp., Campylobacter spp., Escherichia coli and Enterococcus spp., and mastitis-causing bacteria, isolated from swine, chicken, dairy and beef cattle from Argentina. This study gives evidence for supporting the hypothesis that AMR of common food-transmitted bacteria in Argentina is reaching alarming levels. Meta-analyses followed by subgroup analyses confirmed the association between the prevalence of AMR and (a) animal species (p<0.01) for streptomycin, ampicillin and tetracycline or (b) the animal production system (p<0.05) for streptomycin, cefotaxime, nalidixic acid, ampicillin and tetracycline. Moreover, swine (0.47 [0.29; 0.66]) and intensive production (0.62 [0.34; 0.83]) showed the highest pooled prevalence of multidrug resistance while dairy (0.056 [0.003; 0.524]) and extensive production (0.107 [0.043; 0.240]) showed the lowest. A research gap regarding beef-cattle from feedlot was identified. Finally, there is an urgent need for political measures meant to coordinate and harmonize AMR surveillance and regulate antimicrobial use in animal production.

A nontyphoidal Salmonella serovar domestication accompanying enhanced niche adaptation

Invasive nontyphoidal Salmonella (iNTS) causes extraintestinal infections with ~15% case fatality in many countries. However, the mechanism by which iNTS emerged in China remains unaddressed. We conducted clinical investigations of iNTS infection with recurrent treatment failure, caused by underreported Salmonella enterica serovar Livingstone (SL). Genomic epidemiology demonstrated five clades in the SL population and suggested that the international animal feed trade was a likely vehicle for their introduction into China, as evidenced by multiple independent transmission incidents. Importantly, isolates from Clade-5-I-a/b, predominant in China, showed an invasive nature in mice, chicken and zebrafish infection models. The antimicrobial susceptibility testing revealed most isolates (> 96%) in China are multidrug-resistant (MDR). Overall, we offer exploiting genomics in uncovering international transmission led by the animal feed trade and highlight an emerging hypervirulent clade with increased resistance to frontline antibiotics.

Molecular Epidemiology and Virulence of Non-Typhoidal Salmonella in Armenia

In this work, we analysed human isolates of nontyphoidal Salmonella enterica subsp. enterica (NTS), which were collected from salmonellosis cases in Armenia from 1996 to 2019. This disease became a leading food-borne bacterial infection in the region, with the younger age groups especially affected. The isolates were characterised by serotyping, Enterobacterial Repetitive Intergenic Consensus (ERIC-PCR) typing, and whole genome sequencing (WGS). The main serotypes were S. Typhimurium, S. Enteritidis, and S. Arizonae. ERIC-PCR indicated a high degree of clonality among S. Typhimurium strains, which were also multidrug-resistant and produced extended spectrum beta-lactamases. During the study period, the frequency of S. Typhimurium and S. Arizonae isolations decreased, but with the increase in S. Enteritidis and other NTS. A total of 42 NTS isolates were subjected to WGS and explored for virulence-related traits and the corresponding genetic elements. Some virulence and genetic factors were shared by all NTS serotypes, while the main differences were attributed to the serotype-specific diversity of virulence genes, SPIs, virulence plasmids, and phages. The results indicated the variability and dynamics in the epidemiology of salmonellosis and a high virulence potential of human NTS isolates circulating in the region.

Antibiotic resistance and associated resistance determinants in different Salmonella enterica serovars isolated from pigs in Argentina

Background and Aim:

Salmonellosis is one of the most common foodborne diseases in the world, and the increasing antibiotic resistance in Salmonella enterica subsp. enterica recovered from food animals constitutes an important risk from a One Health approach. This study aimed to characterize antibiotic resistance and some of its associated resistance determinants in different S. enterica serovars isolated from pigs in Argentina.

Materials and Methods:

A retrospective study was conducted on Salmonella strains isolated between 2011 and 2015 from pigs in the Pampean region of Argentina. The antimicrobial susceptibility patterns to 21 antimicrobials and some antibiotic resistance determinants were characterized in 55 Salmonella isolates, representing 58 farms.

Results:

We identified 56% (n=30) of the strains as multidrug-resistant, where resistance to tetracycline (62%, n=34), ampicillin (53%, n=29), nalidixic acid (53%, n=29), chloramphenicol (33%, n=18), and trimethoprim-sulfamethoxazole (31%, n=17) was most common. The wide range of resistance to ampicillin correlates with the presence of TEM type β-lactamases in the strains. However, high susceptibility was found in the new generation of β-lactams. Fluoroquinolone resistance is a major concern. Most strains with decreased susceptibility to ciprofloxacin showed gyrA mutations and plasmid-mediated quinolone resistance gene qnrB.

Conclusion:

Here, we identified broad resistance to some antibiotics frequently used in human therapeutics and several easily transferable resistance mechanisms that could endanger public health.

Systematic Review: Nontyphoidal Salmonella in Food from Latin America

In Latin America, nontyphoidal Salmonella (NTS) is one of the most important etiological agents of foodborne infections; it can survive in soil, water, and food even after processing. Here, we aimed to perform a systematic review by collecting data on the prevalence, serotypes, and antimicrobial resistance (AMR) of NTS isolated from different food products in Latin America, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Out of 1766 studies screened, 244 reports from 13 Latin American countries were eligible. Among these, 182 reported NTS prevalence, 87 reported NTS serotypes, and 83 reported serotypes with AMR patterns. The NTS prevalence ranged from 0.005% to 93.3%, regardless of country and food. Meat showed the highest NTS prevalence. Enteritidis, Typhimurium, and Derby were the most frequently observed serotypes in different food products. The serotypes Enteritidis, Typhimurium, and Infantis, isolated from animal products, showed the highest AMR rate. The presence of NTS in fruits and vegetables, which are generally consumed raw or as ready-to-eat food, indicates a high risk of salmonellosis from consuming these foods. Thus, the reduction of this pathogen in the food chain requires a One Health approach, involving good agricultural and manufacturing practices, low antimicrobial use, and proper waste management.

[Microbiological quality of fresh ground beef and detection of pathogens in environmental samples taken from butcher shops in the city of Tandil, Buenos Aires Province, Argentina]

The aim of this work was to evaluate the hygienic-sanitary conditions of butcher shops in Tandil, Buenos Aires Province, by estimating the risk based on good manufacturing and hygiene practices, through surveys of the establishments. The analysis was performed using a scale of 1-100, and classifying them as high risk (0-40), moderate risk (41-70) or low risk (71-100). The presence of Salmonella spp., Staphylococcus aureus and Shiga toxin-producing Escherichia coli (STEC) from both, ground beef and environmental samples such as countertop, cleaver, mincer and butcher's hands, taken at butcher shops was also evaluated. Sampling was performed only once and immediately refrigerated and transported to the laboratory for analysis. All butcher shops evaluated (100) were classified as "low risk" with good hygienic-sanitary conditions. However, 75% of the ground beef samples analyzed did not meet at least one of the microbiological criteria established in the Código Alimentario Argentino [Argentine Food Code], article 255. We propose to establish a strategy to identify deviations and implement a plan for continuous improvement in butcher shops of Tandil city.

Genomic Investigation of Salmonella Isolates Recovered From a Pig Slaughtering Process in Hangzhou, China

The pig industry is the principal source of meat products in China, and the presence of pathogens in pig-borne meat is a crucial threat to public health. Salmonella is the major pathogen associated with pig-borne diseases. However, route surveillance by genomic platforms along the food chain is still limited in China. Here, we conducted a study to evaluate the dynamic prevalence of Salmonella in a pig slaughtering process in Hangzhou, Zhejiang Province, China. Fifty-five of 226 (24.37%) samples were positive for Salmonella; from them, 78 different isolates were selected and subjected to whole genome sequencing followed by bioinformatics analyses to determine serovar distribution, MLST patterns, antimicrobial resistance genes, plasmid replicons, and virulence factors. Moreover, phenotypic antimicrobial resistance was performed using the broth dilution method against 14 antimicrobial agents belonging to 10 antimicrobial classes. Our results showed that samples collected from the dehairing area (66.66%) and the splitting area (57.14%) were the most contaminated. Phenotypic antimicrobial resistance classified 67 of 78 isolates (85.90%) as having multidrug resistance (MDR), while the highest resistance was observed in tetracycline (85.90%; 67/78) followed by ampicillin (84.62%; 66/78), chloramphenicol (71.80%; 56/78), and nalidixic acid (61.54%; 48/78). Additionally, serovar prediction showed the dominance of Salmonella Typhimurium ST19 (51.28%; 40/78) among the 78 studied isolates, while plasmid prediction reported the dominance of IncHI2A_1 (20.51%; 16/78), followed by IncX1_1 (17.95%; 14/78) and IncHI2_1 (11.54%; 9/78). Virulence factor prediction showed the detection of cdtB gene encoding typhoid toxins in two Salmonella Goldcoast ST358 and one Salmonella Typhimurium ST19, while one isolate of Salmonella London ST155 was positive for genes encoding for the siderophore “yersiniabactin” and the gene senB encoding for enterotoxin production. From this study, we conclude that pig slaughterhouses are critical points for the dissemination of virulent and multidrug-resistant Salmonella isolates along the food chain which require the implementation of management systems to control the critical points. Moreover, there is an urgent need for the implementation of the whole genome sequencing platform to monitor the emergence of virulent and multidrug-resistant clones along the food chain.

Virulence genes and antimicrobial susceptibility in Salmonellaenterica serotypes isolated from swine production in Argentina

Salmonella is a worldwide-distributed pathogen that affects both humans and animals and is usually associated with intensive animal production such as poultry and swine. This bacterium carries different virulence genes, whose expression favors its interaction with the host and may influence the course of the infection. Extended usage of antibiotics for metaphylaxis or prophylaxis and as growth promoters favors the emergence of multiresistant Salmonella strains. The aim of this work was to assess the association between the presence of virulence-associated genes and the antimicrobial resistance phenotype in Salmonella isolates obtained from swine intensive and backyard farms in Argentina during 2012-2018. A total of 59 Salmonella strains belonging to several serotypes were studied. All the strains carried the sopB and ssaQ genes, whereas more than 90% of the isolates carried the mgtC, avrA, and siiD genes. Some isolates also carried the bcfC, sodC1, gipA, sopE1 and spvC genes; however, their presence varied among them. Susceptibility to the antibiotics tested was diverse. Isolates from intensive farms were resistant to a larger number of antimicrobials than those from backyard farms and some of the strains showed high virulence potential and extensive antimicrobial resistance profiles. Continuous surveillance is essential to detect the emergence of strains that may represent a significant risk not only for animal production but also for the human population.

Detection of Antimicrobial Resistant Salmonella enterica Strains in Larval and Adult Forms of Lesser Mealworm (Alphitobius diaperinus) From Industrial Poultry Farms

The lesser mealworms (Alphitobius diaperinus) constitute a common cosmopolitan pest in poultry flocks and may colonize the litter in adult and larval forms. Previous studies have documented their potential as carriers of enteric pathogens. In this context, S. enterica constitutes a prioritized zoonotic agent in the poultry industry due to the sanitary risks and economic losses associated with its presence. The aim of this study is to describe the presence of S. enterica strains in larval and adult forms of A. diaperinus collected from poultry litter belonging to industrial farms located in the central zone of Chile. A total of 403 specimens (203 adults and 200 larvae) were sampled from three farms and 25 flocks. For bacteriological isolation, beetles were processed to differentiate external and internal contamination. Then, isolates were serotyped according to the Kauffman-White scheme and antimicrobial resistance phenotypes were determined using the disk diffusion method. Gene sequences from the megaplasmid pESI were identified through a PCR based test. These procedures led to the detection of 15 S. enterica isolates, belonging to serotypes Infantis (14) and Livingstone (1), from both adults (6) and larval (9) specimens, with a similar external (7) and internal (8) distribution. Furthermore, all S. Infantis isolates showed antimicrobial resistance and evidence of megaplasmid pESI carriage, with all possessing multidrug-resistant phenotypes. Our results confirm that A. diaperinus constitutes a potential reservoir of zoonotic Salmonella strains of sanitary and economic concern for the industry and for public health.

Comparative Analysis Using Pulsed-Field Gel Electrophoresis Highlights a Potential Transmission of Salmonella Between Asymptomatic Buffaloes and Pigs in a Single Farm

Buffaloes and pigs play an important epidemiological roll in the Salmonella infection cycle, and asymptomatic animals can act as key component in the dissemination of the disease by horizontal, vertical, and cross-species transmission. Our study aimed and was able to confirm evidences of a cross-species transmission of Salmonella Agona between asymptomatic buffaloes and pigs. Also, we described Salmonella infection within the pig production phases, involving serotypes Agona, Senftenberg and Schwarzengrund. Rectal samples were collected from Jafarabadi buffaloes (n = 25) and Piau pigs (n = 32), located on a single farm. Salmonella Agona was isolated from lactating buffaloes, gilts, pregnant sows, and weaned pigs, Salmonella Schwarzengrund from lactating sows and Salmonella Senftenberg from gilts, pregnant sows, lactating sows, and weaned pigs. Pulsed-field Gel Electrophoresis protocol (PFGE) was performed and revealed four different profiles. Profile 1 (Salmonella Agona), isolated from a pregnant sow, a gilt and two lactating buffaloes, revealed a indistinguishable PFGE pattern, confirming evidences of potential cross-species transmission. Profile 2 (Salmonella Agona), 3 (Salmonella Senftenberg), and 4 (Salmonella Schwarzengrund), isolated from pigs, revealed important indistinguishable PFGE patterns, evidencing Salmonella infection within the pig production phases. Considering the epidemiological relevance of buffaloes and pigs in the cycle of Salmonella infection, confirmation of a potential cross-species transmission of Salmonella Agona and potential Salmonella infection within the pig production phases highlights the importance of the correct establishment of preventive health strategies in farms, in special the importance of avoiding contact between buffaloes and pigs, since cross-species transmission can occur, increasing the risk of spreading the disease.

Nationwide surveillance on serotype distribution and antimicrobial resistance profiles of non-typhoidal Salmonella serovars isolated from food-producing animals in South Korea

Food-producing animals are considered a leading source of human Salmonella infections in Korea. However, there is a lack of comprehensive and up-to-date data regarding the diversity and resistance profiles of Salmonella serotypes in these animals. Therefore, this study aimed to determine the distribution and antimicrobial resistance profiles of Salmonella serotypes isolated from cattle, pigs, and chickens in Korea between 2010 and 2018. A total of 3018 Salmonella isolates were obtained from 16 laboratories/centers participating in the Korean Veterinary Antimicrobial Resistance Monitoring System. Salmonella serotypes were identified from the following isolates: 179 cattle (17 serotypes), 959 pig (45 serotypes), and 1880 chicken (64 serotypes). The most frequent serotypes in cattle (Typhimurium, Salmonella 4,[5],12:i:-, and Schwarzengrund), pigs (Typhimurium, Rissen, and S. 4,[5],12:i:-), and chickens (Enteritidis, Albany, Virchow, and Montevideo) accounted for more than 50% of the total serotypes in the respective animal species. To the best of our knowledge, Salmonella 4,[5],12:i:- has not been identified in cattle in Korea to date. More than 80% of the isolates demonstrated resistance to at least one antimicrobial agent. Multidrug-resistance was found in almost half of the serotypes; the highest proportion in cattle (59.2%), followed by pigs (53.4%), and chickens (45.7%). Significant proportions of the serotypes were resistant to ampicillin, streptomycin, and tetracycline. Ceftiofur and ciprofloxacin resistance rates were the highest in Salmonella isolated from chickens (17.1% and 4.1%, respectively) and cattle (10.1% and 3.9%, respectively) compared to that in pigs. Among the frequent serotypes, Albany demonstrated the highest resistance rate (>90%) to five different antimicrobials. Alarmingly, some Salmonella serotypes that are frequently associated with human infections demonstrated a trend of increasing resistance to critically important antibiotics, including 3rd generation cephalosporins and quinolones. Collectively, the presence of antibiotic-resistant Salmonella in food-producing animals poses a potential risk to public health.

Prevalence, associated risk factors, and antimicrobial resistance profiles of non-typhoidal Salmonella in large scale swine production in Córdoba, Argentina

Non-typhoidal Salmonella is considered a major public health concern. The growing relevance of pigs as reservoir of Salmonella spp. has prompted several countries to set up surveillance and control programs to fight Salmonella infection in swine and reduce public health risk. In the last decade, pork production in Córdoba increased significantly to become one of the most important pig production provinces in Argentina. The aim of this study was to estimate Salmonella spp. prevalence and associated risk factors in large scale-farms in this province. Mesenteric lymph nodes (MLN) of 580 pigs from 20 finishing large-scale farms were collected between 2014 and 2015 to estimate Salmonella infection. A prevalence of 41.5% (95%CI: 37.6-45.6%) was observed. Two major risk factors were significantly associated with Salmonella infection, both related to the pre-slaughter period (distance from the farm to the slaughterhouse and lairage time), highlighting the need to pay special attention to pre-slaughter practices in the province. Shortening transport times and complying with national regulations for lairage time at slaughter may help to reduce the prevalence of infection. Sixteen different serovars were identified, being S. Anatum and S. Typhimurium the most prevalent ones. Moreover, two isolate of the monophasic variant of Salmonella Typhimurium (I 4,5,12:i:-) resistant to enrofloxacin and which also displayed multidrug resistance was isolated for first time from pigs in Córdoba. The moderate to high levels of antimicrobial resistance detected for antibiotics commonly used in the pig sector suggested the need for implementing a plan to limit their use in the province.

Contamination of pig carcass with Salmonella enterica serovar Typhimurium monophasic variant 1,4[5],12:i:- originates mainly in live animals

Pork is considered a major source of Salmonella Typhimurium infection in humans in the EU, including monophasic strains (mST). Widespread distribution of virulent serotypes such as monophasic variants of S. Typhimurium have emerged as a public health threat. Despite the current situation, within the EU there is no mandatory programme for the control of Salmonella at pork production level. In this context, the aims of this study were: to examine the presence of Salmonella in the swine production system from arrival at the slaughterhouse until the end of processing, and investigate the genetic relationship among serovars. A total of 21 pig herds were intensively sampled during processing at the slaughterhouse. ERIC-PCR followed by PFGE were performed among isolates recovered at the different steps in the slaughterhouse to assess their genetic relationship. The results showed a high level of Salmonella pork batch contamination upon arrival at the slaughterhouse (71.4%) and at the end of the slaughtering process (66.7%), with mST the main serovar isolated from both origins (53.1% and 38.2%, respectively). Similarly, this study shows that 14.3% of the strains isolated from carcasses have the same Xbal-PFGE profile as those previously recovered in the slaughterhouse environment, but not in the live animals from that same batch. In conclusion, there is a high level of Salmonella swine batch contamination upon arrival at the slaughterhouse and at the end of the slaughtering process, mST being the most frequently isolated serovar. Moreover, a strong genetic relationship has been observed between strains isolated from the batch on arrival at the slaughterhouse, the processing environment and pork carcass contamination. In this sense, it would be necessary to implement a control programme to reduce the bacterium from pork farms and raise the awareness of biosecurity measures.

Recombinase Polymerase Amplification (RPA) Combined with Lateral Flow Immunoassay for Rapid Detection of Salmonella in Food

Salmonella can cause serious foodborne diseases. We have developed a lateral flow immunoassay combined with recombinase polymerase amplification (LFD-RPA) for detection of Salmonella in food. The conserved fragment (fimY) was selected as the target gene. Under an optimal condition (37 °C, 10 min), the sensitivity was 12 colony-forming units (CFU)/mL in a pure culture. Testing with 16 non-Salmonella strains as controls revealed that LFD-RPA was specific to the fimY gene of Salmonella. The established assay could detect Salmonella at concentrations as low as 1.29 × 10² CFU/mL in artificially contaminated samples. This detection was at a slightly higher level than that for a pure bacterial culture. Combined with the test strip reader, the LFD-RPA is a feasible method for quantitative detection of Salmonella based on the test line intensity, which was the ratio for the test line and control line of the reflected light. The method could be a potential point-of-care test in limited resource areas and provides a new approach and technical support for the diagnosis of food safety.