Microbial Challenge Testing for Foods Workshop



Register Today – seats are limited!

Embassy Suites O’Hare Hotel
Rosement, Illinois
(This location offers easy access for attendees using O’Hare Airport in Chicago.)


The food industry routinely uses challenge testing to determine whether a specific food requires time and temperature control for safety, or is suitably formulated. When laboratory testing is used to support a change in how the product is handled in a food establishment (e.g., refrigerated to unrefrigerated holding, extending shelf life, increasing ambient temperature storage or eliminating the need for date marking), the data are submitted to a state or local regulatory agency or directly to the FDA in the form of a variance application for approval. Food establishments or manufacturers submitting laboratory data to support their proposals must ensure the study is appropriate for the food and pathogen of concern and incorporate the necessary elements into the study to yield a valid design and conclusion. Because of the many questions raised by regulatory and industry professionals about the appropriate use of challenge studies, the National Advisory Committee on Microbiological Criteria for Foods (NACMCF) was asked to provide guidance on the topic of challenge studies and their use. This workshop will present the NACMCF report and instructors will guide the students though use of the material in the report to develop actual challenge study protocols based on NACMCF recommendations.


•     Overview of challenge study design (purpose of study, product description, product assessment, pathogens of concern, sampling intervals, test conditions, other controls, pass/fail criteria).

•     Introduction to models and their use (examples of models, applicability of models to different foods, pathogen growth ranges used in modeling programs).

•     Purpose of study, product description and assessment (purpose of the study, time/temperature control, lethality, formulation efficacy, product, ingredients, preparation, storage, ph and water activity).

•     Pathogens of concern (selection criteria, ecology and epidemiology, use of models and the literature, inactivation study parameters).

•     Sampling intervals and test conditions (growth vs. inactivation studies, strain selection, inoculation methods, packaging, sample size and replicates).

•     Other controls and pass/fail criteria (surrogates, un-inoculated controls, pass/fail criteria selection and limitations of study).

Kathy Glass, University of Wisconsin-Madison
Linda Harris, University of California-Davis
Don Schaffner, Rutgers, The State University of New Jersey

Don Schaffner, Rutgers, The State University of New Jersey

Intended Audience:
Food industry professionals, testing lab personnel and regulators