Foodborne Enteric Pathogen Testing


To assist with national and state surveillance, and subsequent epidemiological investigations, of diarrheal infectious diseases linked to food by providing an array of molecular and conventional detection and characterization methods for enteric pathogens isolated from food and/or patient specimens. These enteric pathogens include Salmonella spp., Campylobacter spp., Shigella spp., toxigenic Escherichia coli (e.g. O157:H7), Listeria monocytogenes, Vibrio spp., Yersinia spp., and norovirus, among other food-borne illnesses.

What we do

  • Test clinical specimens and microbiological isolates routinely submitted by hospital and commercial laboratories, health centers, the Rhode Island State Medical Examiner, and medical practitioners throughout the state for the presence of infectious diarrhea-causing pathogens of public health significance.
  • Characterize detected enteric pathogens and help to define and track outbreaks by a variety of methods including serotyping and serogrouping, as well as genotyping by molecular "DNA fingerprinting" methods, such as Pulsed-Field Gel Electrophoresis (PFGE) and Whole Genome Sequencing (WGS), to support state and national epidemiological investigations.
  • Participate in Centers for Disease Control (CDC) programs such as PulseNet and the National Antimicrobial Resistance Monitoring System for Enteric Bacteria (NARMS) for the national and international epidemiologic tracking of foodborne pathogens and illnesses and to provide continuous monitoring of antimicrobial resistance in enteric bacterial isolates.
  • Share test results with the RIDOH Center for Acute Infectious Diseases and Epidemiology (CAIDE)to assist them with surveillance for the presence and spread of enteric pathogens with outbreak potential in Rhode Island.
  • Support foodborne illness surveillance initiatives of the RIDOH Center for Food Protection and the Food and Drug Administration (FDA) Food Emergency Response Network (FERN) by providing accurate and prompt food testing capabilities following the ISO/IEC 17025 quality standard for the Food Testing Laboratories.
  • Enable the prompt investigation of problems identified in the food supply including, but not limited to, the removal of enteric pathogen-contaminated products from the market.
  • Maintain readiness to provide increased sample analyses in the event of food outbreaks or other large-scale food emergency events requiring surge capacity testing of implicated food samples.


  • Introduced Whole Genome Sequencing (WGS) into routine laboratory practice as part of a CDC capacity-building initiative amongst the network of U.S. state Public Health Laboratories. The Rhode Island State Health Laboratory (RISHL) currently sequences all Salmonella enterica, toxigenic E. coli, and Listeria monocytogenes isolates from food and clinical specimens.
  • Participated in food surveillance activities to protect public health, such as the screening of sandwiches from a school lunch program and other targeted food surveillance activities, including the screening for Campylobacter spp. in restaurant-prepared chicken liver pâté and Salmonella in Egg Nog, as well as surveillance testing of grocery store produce and prepared foods and the environmental testing for Listeria in grocery store deli slicers that has resulted in improved sanitary maintenance in (previously) contaminated deli environments.
  • Participated in epidemiological investigations, such as ruling-in or ruling-out potential Norovirus outbreaks in nursing homes, Shigella infections linked to swimming in two northern Rhode Island lakes (118 clinical cases), and uncovering the source of Salmonella contamination in an outbreak linked to the black and red pepper used in deli meats and resulted in a recall of the contaminated products (272 cases nationwide).
  • Participated in a multi-DOH agency investigation of a recent large outbreak of diarrheal illnesses (> 50 affected Rhode Island residents) linked to a sandwich shop. Using cutting edge molecular diagnostic methodologies recently introduced to the laboratory, the RISHL was able to rapidly identify the causative bacterial agents of the outbreak and thereby focus subsequent investigations of the outbreak.
  • Isolated a shiga-toxin producing E. coli from a Rhode Island resident and used WGS to link it to a 6 month long, multi-state, outbreak. The Rhode Island State Health Laboratory then isolated the same strain of E. coli from flour that the resident had consumed. This resulted in a recall of the implicated brand of all-purpose flour and lead to further investigations by the FDA of the original flour source.