Hurdle technology Flashcards
Defn
an intelligent combination of hurdles which secures microbial safety and stability as well as the organoleptic and nutritional quality of food
organoleptic
sensory chsracteristics of food eg. smell taste texture
why do we need hurdle technology
The goal is to create a more robust and effective preservation system than using a single preservation method
intrinsic factors for MO growth
pH, water activity, nutrient factor, oxygen availability
extrinsic factors for MO growth
temperature, relative humidity, gaseous environment, pressure, radiaition, packaging
3 types of hurdles
Physical, physiochemical, microbial
physical hurldes
aseptic packaging, high temperatures (blanching), low temps. (freezing), electromagnetic energy ( Pulse magnetic fields, high electric fields) Ultra high pressures
physiochemical
lactoperoxidase, salt, smoking,spices, herbs
microbial
antibiotics, bacteriocins, protective cultures
discuss water activity
amount of free water in a product as opposed to bond water
free water
inside cells, maintains properties of water, may be removed by pressure
bound water
part of molecualr structures, reduced mobility, does not retain the characteristics of water
why is water activity important for hurdle technology
most bacteria do not grow at water activities below 0.91 and most moulds do not grow below 0.8
Aw of fruit
0.98 and above
Aw od choc, honey, biscuits and potato chips
below 0.60
