NU FS363 Lecture Notes - Lecture 7: Water Activity, Egg White, Aspergillus
1 Nov 2016
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Lecture 7 & 8: define extrinsic factor. Extrinsic factors are properties of the environment and can be controlled by your storage environment i. e. where you put the food. Ex. temperature, presence and concentration of gases and relative humidity: define intrinsic factor. Intrinsic factors have to do with the properties of the food (or plant and animal tissue) and are controlled by the raw material or by the product formulation i. e. what you put in the food. Temperature is the most important determinant of microbial growth in food. The parameters that are helpful to us are: minimum temperature of growth (tmin, optimum temperature of growth (topt, maximum temperature of growth (tmax) These parameters are specific for the conditions and the bacterial species: describe a microbial growth curve. There are 4 distinct phases: lag phase the start of the curve, exponential growth phase the portion of the curve with an positive slope.
