Thermal resistance of bacteria
The higher the thermal resistance of a bacteria, the harder it is to inactivate that bacteria within a substance. Therefore, we performed a study of thermal resistance using two different types of substances: all-purpose flour and peanut butter. We created isotherms to map the relationship between the water activity and moisture content in these two samples.
In this experiment, we examined the impact of temperature on the capacitance of polymer film, relative humidity, and water activity. The thermal resistance of the flour and the peanut butter differed, even though they were subject to the same temperature increase. This reinforces that in food production, it is important to remember that the thermal resistance of bacteria will differ depending on the substance.
Inactivation of pathogens is achieved through a complicated process: inoculation, equilibration (e.g., control humidity), fabrication (e.g., grind, mill, etc.), re-equilibration (five to twelve days), and treatment through bench scale (iso- and non-iso-) and pilot-scale.
Low water activity and low moisture content products
When working with any substance, inoculation is a crucial step and affects the resistance of any bacterial organisms. Several product treatments are available to inoculate and further test bacterial thermal resistance. These treatments include bench scale, isothermal, and pilot scale. All of these involve monitoring the temperature and humidity in an environment. A product’s starting water activity level will directly impact the thermal resistance of the present bacteria.