Food safety professionals have always been faced with “difficult to inactivate” pathogens, most of which have provided the motivation for the historical development of food processing technologies ranging from commercial sterilization to ionizing radiation. Advances in science have provided explanations for why these microbes are difficult to inactivate, but also conditions that make otherwise sensitive organisms more difficult to kill. The purpose of this session is to identify which microbes can be classified as “difficult to inactivate;” what general features make them so; what conditions contribute to making pathogens more difficult to inactivate; and current and emerging best practices for their removal and inactivation.
The audience will gain a better understanding of the importance and challenges associated with controlling certain viruses (e.g., norovirus and hepatitis A virus), bacteria (e.g., spore-formers and Listeria monocytogenes) and parasitic protozoa (e.g., Toxoplasma gondii, Cyclospora cayetanensis) that are otherwise recalcitrant to many methods commonly used by the food industry, and conditions (e.g., biofilms, internalization) that promote persistence and resistance.