About

Jianghong Meng is a Professor in the Department of Nutrition & Food Science at the University of Maryland, College Park. His research focuses on food safety microbiology, specifically molecular identification, antimicrobial resistance, and pathogenicity of major foodborne pathogens including Shiga toxin-producing Escherichia coli, Campylobacter, Salmonella, and Listeria monocytogenes. Dr. Meng holds a Ph.D. in Comparative Pathology from the University of California, Davis, a Master of Preventive Veterinary Medicine from UC Davis, and a DVM from Sichuan Agricultural University in China. He serves as the Director of the Center for Food Safety and Security Systems and the Joint Institute for Food Safety & Applied Nutrition. Dr. Meng has received numerous awards and honors, including Fellowships in the American Academy of Microbiology and the International Association for Food Protection, as well as awards from the US Food & Drug Administration and the USDA. His professional service includes participation in various national and international committees and panels related to food safety microbiology, antibiotic resistance, and public health data. His contributions significantly advance understanding in food safety microbiology, antimicrobial resistance, and pathogen detection.

Research topics

• Genetics
• Computational biology
• Biology
• Materials science
• Nanotechnology

Selected publications

• Tracking Antimicrobial Resistance in Salmonella via Poultry Supply Chains, Human Clinical Samples, and Environmental Reservoirs

  Foods · 2026-01-23 · 2 citations

  articleOpen access

  The global dissemination of multidrug-resistant (MDR) Salmonella through the international food trade poses a major One Health concern. We used whole-genome sequencing to characterize Salmonella isolates from poultry meat sold in Chile, including domestic and imported products from Brazil and Argentina. Sixty-one Salmonella isolates were recovered from poultry meat; S. Infantis predominated (59%), followed by S. Heidelberg. Among S. Heidelberg from imported-meat poultry, 92% carried the blaCMY-2 gene, conferring resistance to β-lactams. Given the predominance of S. Infantis in poultry meat, we performed an additional in-depth genomic analysis of 73 S. Infantis isolates obtained from poultry meat (n = 32), surface water (n = 30), and human clinical cases (n = 11). Across sources, phenotypic resistance to ciprofloxacin and third-generation cephalosporins reached 93% and 70%, respectively, and MDR (≥3 antimicrobial classes) occurred in 71% of isolates, largely associated with blaCTX-M-65 and gyrA mutations. The pESI (plasmid of emerging S. Infantis)-like plasmid, harboring antimicrobial resistance and virulence genes, appeared in 94% of isolates. Phylogenetic analyses showed close genetic relationships among food, environmental, and clinical isolates, suggesting potential transmission through contaminated poultry meat or water. These findings emphasize the emergence of MDR S. Infantis in Chile and underscore the need for integrated One Health surveillance and prudent antimicrobial use to mitigate foodborne AMR risks.

  PublisherOA PDFDOI

• Draft genome sequences of <i>Salmonella</i> recovered from organic and conventional retail chickens in Maryland, USA

  Microbiology Resource Announcements · 2025-02-21 · 1 citations

  articleOpen access

  ABSTRACT We report the draft genome sequences of 94 multidrug-resistant Salmonella isolates ( S . Infantis, Enteritidis, and Typhimurium) from organic and conventional retail chickens in Maryland, USA (average genome size = 4.97 Mb; guanine–cytosine content = 52.12%). These isolates harbored diverse antimicrobial resistance and virulence genes, Salmonella pathogenicity islands, and plasmids, highlighting potential public health risks.

  PublisherDOI

• Evolving Threats: Leveraging <i>C. elegans</i> to Decode the Virulence Profiles of Highly Related Environmental <i>Salmonella</i> Newport Isolates

  bioRxiv (Cold Spring Harbor Laboratory) · 2025-09-29

  preprintOpen access

  Abstract Salmonella enterica subspecies enterica , particularly serovar Newport, remains a leading cause of foodborne illnesses in the United States, implicated in numerous outbreaks associated with a diverse array of food products. This study rigorously investigates the virulence of five distinct S . Newport isolates, characterized by varying patterns of pulse-field gel electrophoresis (PFGE) molecular-diagnostic subtyping, using the nematode Caenorhabditis elegans as a host model organism. We conducted viability assays on C. elegans to evaluate how these isolates affect nematode survival. The selected bacterial strains, rooted in historical foodborne outbreak significance but environmentally isolated, were previously sequenced to provide a comprehensive genomic framework. A notable focus of our research was on the nearly genetically identical PFGE types Newport-61 and the Newport-1015 isolates, which differ by a ∼1.7 Mb genomic inversion. C. elegans survival assays in response to pathogenic-strain infections revealed that one Newport-1015 and the Newport-61 were particularly more virulent compared to other strains tested. These findings enhance our understanding of the pathogenic potential of environmental S . Newport and highlight the need to understand the regulatory mechanisms that contribute to virulence capacity.

  PublisherOA PDFDOI

• Whole genome sequencing of Salmonella serovars isolated from organic and non-organic whole broiler carcasses on the eastern shore of Maryland, USA

  Food Research International · 2025-04-17 · 2 citations

  articleOpen access

  Multidrug-resistant Salmonella is becoming a public health hazard. This study aimed to investigate the genomic diversity of the selected Salmonella serovars isolated from organic and non-organic chickens using whole-genome sequencing (WGS). A total of 94 Salmonella isolates [Infantis ( n = 71), Enteritidis ( n = 13), Typhimurium ( n = 10)] recovered from organic and non-organic retail chickens were subjected to WGS using Illumina MiSeq. All Salmonella isolates contained at least one antibiotic resistance (AR) gene (ARG). All S. Typhimurium and S. Enteritidis isolates, and 98.6 % of S. Infantis isolates possessed aac(6′)-Iaa which predicted resistant to aminoglycosides. Most isolates harbored ARGs for sulfonamides, β-lactamase inhibitors, tetracyclines, and fluoroquinolone/quinolone resistance regardless of chicken types. Fisher's exact test indicated a significantly higher prevalence of ARGs in Salmonella isolated from organic chickens. The virulence genes that stimulate Salmonella pathogenicity island 1 (SPI1) encoding, type three secretion system 1 (TTSS-1) translocated effectors, SPI2 encoding, TTSS-2 translocated effectors, fimbrial adherence determinants, serum resistance, stress adaptation and Mg 2+ uptake were observed in every serovar regardless of chicken types. Seven plasmids were detected in Salmonella isolates from non-organic chicken, including IncFIB(pN55391), IncFIB(S), Col(BS512), IncFII(S), IncX1, IncC, and ColpVC, whereas Salmonella isolates from organic chicken carried only three plasmids [IncFIB(pN55391), Col(BS512), and IncC]. Phylogenetic analysis confirmed that a significant portion of the isolates had single nucleotide polymorphism (SNP) distances greater than the threshold (SNP ≤ 20), indicating genetic distance among them. These results suggest that the Salmonella isolates from organic and non-organic chickens possessed various AR and virulence genes and thus have the potential to cause salmonellosis. • High prevalence of Multi-Drug resistance Salmonella detected in retail chicken. • Higher antibiotic resistance genes were observed in Salmonella from organic chicken. • Virulence genes and SPIs indicate the invasive potential of Salmonella serovars. • IncFIB(pN55391) plasmid in S. Infantis suggests possible pESI-like megaplasmids. • Genotype-phenotype inconsistencies reveal the complexity of resistance mechanisms.

  PublisherDOI

• Water sampling using modified Moore swab (MMS): the effects of sampling replicates and different media on the frequency and diversity of <i>Salmonella</i> serovars

  Applied and Environmental Microbiology · 2025-07-24 · 4 citations

  articleOpen access

  ABSTRACT Salmonella enterica is a significant foodborne pathogen frequently associated with produce contamination through irrigation with untreated surface water. This study investigated the effects of sampling replication and selective media on S. enterica serovar recovery and diversity in surface waters across Paraíba State, Brazil. Water samples ( n = 200) were collected from 10 reservoirs using modified Moore swabs (MMSs), with three replicates per sampling site, yielding 600 samples. The prevalence of S. enterica was 53.5% in individual samples, increasing to 68.5% when combining results from triplicate samples. Statistical analyses demonstrated that triplicate sampling significantly enhanced both recovery rates and serovar diversity compared with single samples ( P &lt; 0.05). Alpha diversity metrics revealed a 39% increase in serovar richness when using triplicate versus single samples. The parallel use of multiple enrichment broths and selective agars proved essential for maximum serovar detection, as certain serovars were recovered exclusively under specific culture conditions. While triplicate sampling provided optimal detection sensitivity, duplicate sampling emerged as a cost-effective alternative, maintaining sufficient statistical power. These findings demonstrate the effectiveness of MMS combined with replicate sampling for comprehensive S. enterica surveillance in surface waters, with implications for water quality monitoring programs and public health risk assessment. IMPORTANCE Salmonella contamination in irrigation water poses a major threat to food safety, as contaminated produce can cause widespread foodborne illness outbreaks affecting thousands of people. Current water monitoring methods often miss these hazardous bacteria, creating blind spots in our food safety systems. This research addresses a critical gap by demonstrating that taking multiple water samples from the same location, rather than just single samples, improves our ability to detect Salmonella contamination. The study shows that collecting three samples instead of one increases the detection rate from 54% to 69% and reveals nearly 40% more serovars. This enhanced detection capability is crucial for protecting public health, as it provides more accurate information about the occurrence of Salmonella in natural surface waters. Lastly, our findings provide practical guidance for improving surveillance programs worldwide, offering a cost-effective approach that significantly strengthens our defense against Salmonella contamination in the food supply chain.

  PublisherDOI

• High Prevalence of Plasmid‐Mediated Quinolone Resistance in <i>Salmonella enterica</i> Serovars Isolated From Surface Water

  Environmental Microbiology · 2025-07-01 · 2 citations

  articleOpen access

  Considering the increasing reports of Salmonella enterica strains resistant to quinolones, antimicrobials frequently employed as therapeutic agents globally, our goal was to investigate the occurrence of plasmid-mediated quinolone resistance (PMQR) determinants in S. enterica recovered from natural surface waters in Paraíba state, Brazil. Water samples (n = 230) were collected monthly in triplicate using modified Moore swabs from 29 sampling sites belonging to 10 large dams. After conventional microbial isolation, representative isolates (n = 938) were submitted to whole genome sequencing, assembly and annotation. Antimicrobial resistance genes (ARGs) were identified, and core genome multilocus sequence typing (cgMLST) was used to infer phylogenetic relationships. Among recovered S. enterica, 130 (13.9%) isolates harboured PMQR determinants; 124 (95.4%) harboured qnrB19, while 6 (4.6%) harboured qnrS1. Multiple other ARGs associated with resistance to aminoglycosides, β-lactams, sulphonamides, tetracyclines and fosfomycin were identified. The diversity of ARGs and plasmids suggests a highly complex resistance landscape. Phylogenetic analysis revealed clustering by serovar and sequence type but not by resistance profile or geographic origin. The absence of association between phylogeny and ARGs highlights the potential role of horizontal gene transfer in disseminating resistance genes in water. Our findings reinforce the importance of antimicrobial resistance surveillance in surface waters.

  PublisherOA PDFDOI

• Sequential combination of gaseous chlorine dioxide and ultraviolet-C: Tackling sub-lethally stressed Salmonella enterica on raw whole almonds and fresh-cut leafy greens

  Food Research International · 2025-08-29 · 1 citations

  articleSenior author
  PublisherDOI

• Genomic diversity and environmental factors associated with Listeria monocytogenes presence in surface water

  The Science of The Total Environment · 2025-09-17

  article
  PublisherDOI

• Erratum for Ferreira et al., “Closed genome sequences of 14 <i>Salmonella enterica</i> serovar Newport isolates from various sources”

  Microbiology Resource Announcements · 2025-08-27

  erratumOpen access
  PublisherDOI

• Closed genome sequences of 14 <i>Salmonella enterica</i> serovar Newport isolates from various sources

  Microbiology Resource Announcements · 2025-03-13 · 2 citations

  articleOpen access

  ABSTRACT Salmonella enterica serovar Newport is a major contributor to the burden of salmonellosis in the United States. We report the closed genomic sequences of 14 S . Newport isolates collected from various sources in the United States. All consist of one circular chromosome, and eight have at least one circular plasmid.

  PublisherDOI

Recent grants

• Cooperative Agreement to Support the Joint Institute for Food Safety and Applied Nutrition (JIFSAN)

  NIH · $53.1M · 1997–2027

Frequent coauthors

• Shaohua Zhao

  United States Food and Drug Administration

  172 shared

• Eric W. Brown

  Society for Healthcare Epidemiology of America

  144 shared

• Marc W. Allard

  Center for Food Safety and Applied Nutrition

  103 shared

• Patrick F. McDermott

  United States Food and Drug Administration

  99 shared

• Guojie Cao

  Center for Food Safety and Applied Nutrition

  79 shared

• Xuebin Xu

  Xinjiang University

  72 shared

• Zhao Chen

  Center for Food Safety and Applied Nutrition

  66 shared

• Dai Kuang

  Ruijin Hospital

  66 shared

Awards & honors

• Fellow, American Academy of Microbiology
• Fellow, International Association for Food Protection
• Commissioner’s Special Citation Award, the US Food & Drug Ad…
• Outstanding Service Award, the National Advisory Committee o…
• FDA/CFSAN Director’s Special Citation Award on Aquacultural…