Validation of Ingredient-based Systems to Control Pathogens

The safety of a processed low-acid food is assured by controlling acidity, water activity, antimicrobials, and processing or storage temperatures. Additive or synergistic interaction of these factors can lead to lower usage levels of added antimicrobial agents, and thereby enhance the sensory and functional properties of the food.  Due to the complex interaction among these factors, predictive models generated in laboratory media may be insufficient to justify choices of control measures when creating a food safety plan. Therefore, identifying relevant parameters and limits require microbial challenge studies in specific foods.  Groups such as the National Advisory Committee for Microbiological Criteria of Foods (NACMCF), Health Canada, and New South Wales Food Authority provide guidelines for conducting challenge studies. However, even experts food microbiologist may overlook the significance of intrinsic antimicrobial factors or the impact of microbial ecology of a food that change as formulations and ingredients evolve. This presentation will highlight the basics of conducting challenge studies and provide examples of factors that may be unrecognized as being critical for safety.