USDA ARS Food Safety Microbiology Postdoctoral Fellowship

Organization

U.S. Department of Agriculture (USDA), Agricultural Research Service (ARS), located in Beltsville, Maryland.

USDA-ARS-NEA-

2/27/2026 3:00:00 PM Eastern Time Zone

The Agricultural Research Service (ARS) is the U.S. Department of Agriculture's chief scientific in‑house research agency with a mission to find solutions to agricultural problems that affect Americans every day from field to table. ARS delivers cutting‑edge scientific tools and innovative solutions for American farmers, producers, industry, and communities to support the nourishment and well‑being of all people; sustain our nation’s agroecosystems and natural resources;

and ensure the economic competitiveness and excellence of our agriculture. The vision of the agency is to provide global leadership in agricultural discoveries through scientific excellence.

The mission of this research is to improve food safety and reduce foodborne illness by examining routes of contamination of fruits and vegetables with bacterial pathogens.

The research project focuses on critical points of bacterial contamination, specifically colonization of dairy animals and contamination of dry dairy processing facilities. The participant will investigate pathogen dynamics in dry dairy products within an integrated food safety systems framework, studying high‑risk bacterial pathogens:
Salmonella enterica, Escherichia coli (STECs/O157:

H7), and Listeria monocytogenes. Activities include characterizing pathogenic enteric bacteria on dairy farms, their ecology, and routes of transmission, examining production environments that support bacterial pathogen survival under non‑optimal growth conditions, quantifying pathogen survival and persistence, and studying interactions between saprophytic and pathogenic enteric bacteria. The participant will work on laboratory studies and field investigations using digital PCR (dPCR), multiplex PCR, automated nucleic acid extraction, and microbial community analysis (metagenomics/bioinformatics).

Opportunities also exist to design and validate science‑based interventions—such as biological controls using plant‑derived bioactive compounds—to reduce pathogenic bacterial loads and mitigate virulence across the dairy supply chain. The participant will learn statistical analysis of data in consultation with ARS colleagues.

• Bacterial Hazard Characterization and Quantification:
  Learn advanced molecular and non‑destructive sensing methods to identify, quantify, and track the prevalence and spatial dissemination of pathogenic enteric bacteria across dairy‑related matrices.
• Persistence Modeling and Risk Assessment:
  Develop ecological and kinetic models incorporating environmental, microbial community, and survival data to predict bacterial contaminant introduction, persistence, and transfer in the dairy system.
• Intervention Strategy Development and Optimization:
  Utilize advanced data analysis tools, including bioinformatics and introductory data science skills, to design, validate, and optimize mitigation strategies to reduce pathogenic bacterial levels.

Manan Sharma (manan.sharma) and Bradd Haley (bradd.haley). If you have questions about the nature of the research, please contact the mentors.

Anticipated

Start Date:

2025/2026 (flexible). Appointment Length:
One year, may be renewed upon recommendation of ARS and availability of funds. Level of Participation:
Full time.

The participant will receive a monthly stipend commensurate with educational level and experience. Anticipated stipend range: $6,277 – $6,897 per month.

Only U.S. citizens are eligible.

This program, administered by ORAU through its contract with the U.S. Department of Energy (DOE) to manage the Oak Ridge Institute for Science and Education (ORISE), was established through an interagency agreement between DOE and ARS. Participants do not become employees of USDA, ARS, DOE or the program administrator, and there are no employment‑related benefits. Proof of health insurance is required for participation in this program;

health…