IAFP 2025

Session #1: Symposium: Spores…Let’s B. cereus

Abstract: Bacillus cereus is a common spore forming bacteria that can cause foodborne illness if cells grow to sufficiently high levels (e.g., 10⁵ organisms per g) in a food.  Symptoms are exhibited between 1 and 15 hours and typically last only 24-48 hours, depending on whether emetic or diarrheal toxins are present in the food.  The agent is responsible for approximately 64,000 cases in the United States annually, but most cases go unreported because symptoms resolve without medical treatment.  While starchy foods such as rice, beans and pasta are frequently associated with outbreaks, the ubiquitous distribution of the spores makes any food susceptible. Of particular concern is the growth of psychrotrophic strains in refrigerated meals, particularly in plant-based foods including milk analogs, and mesophilic strains during extended runs or extended cooling. Production of heat-stable emetic toxin is problematic because further cooking will not inactivate the toxin. This symposium will provide an overview of the prevalence of the spores, outbreaks which demonstrate lack of control, risks associated with psychrotrophic strains, and issues associated with enterotoxin detection.  Lastly, strategies for inhibition of growth during processing and storage will focus on effective formulation changes along with balancing pathogen growth vs. spoilage.

Speakers:

• Why Should Bacillus cereus be a Priority in a Food Safety Plan?
  • Jasna Kovac, PhD Penn State University
• Recent Improvements in Methodology for Detection of Cells and Toxins
  • Stephanie Smith, PhD Washington State University
• Control Measures Needed During Processing and Storage
  • Kristin Schill, PhD University of Wisconsin-Madison

Session #2: Symposium: Uncharted Territory: The Importance of Genomic Surveys of Foodborne Pathogens from “Uncommon” Environments

Abstract: Pathogen genomic databases have become essential tools for ensuring food safety. The data primarily come from clinical, food, and food production environment samples. However, national genomic surveys of foodborne pathogens from diverse environments, such as consumer households or pristine environments (ie., undeveloped natural settings) provide important insights supporting outbreak investigations, comprehensive assessments of contamination risk, and prioritization of surveillance efforts.

National genomic surveys can reveal differences in regional distribution of pathogen subtypes across the U.S. These surveys help identify the prevalence of pathogens in non-food production environments, and genomic data from these pathogens shed light on possible routes of pathogen transmission. For example, a clinical isolate that is closely related to an isolate found in a pristine environment suggests a complex route of pathogen transmission, which can aid our understanding of produce safety. Large surveys of pathogens in household settings provide much needed data on the role of cross-contamination that occurs in the home. For example, genomic surveys of Cronobacter spp. from households reveals the need for risk mitigation strategies from consumers to compliment the strategies implemented by dry dairy and infant formula companies during product manufacturing.

In this session, we will discuss these databases, and data gaps where national genomic surveys of foodborne pathogens can support identification of matches between clinical specimens and non-clinical isolates. Then we will share examples from two national genomic surveys of foodborne pathogens. The next talk will focus on a longitudinal sampling effort in 120 households across the U.S. Finally, we will address outcomes from a large genomic survey of foodborne pathogens collected from natural environments.

Speakers:

• Genomic Diversity and Persistence of Salmonella in Surface Waters from the Andes Mountains to the Pacific Ocean
  • Andrea Moreno Switt, PhD, Catholic University of Chile
• Nationwide Genomic Survey of Foodborne Pathogens Isolated from Households to Understand Prevalence, Persistence and Risk Factors in Consumer Homes
  • Abby Snyder, PhD, Cornell University
• Genomic “Mapping” Surveys of Listeria and Cronobacter Isolated from Pristine Natural Environments Across the United States
  • Martin Wiedmann, PhD, Cornell University