Principles behind food preservation techniques, including temperature control and restriction of moisture, exclusion of air and pH.
Spend 10 minutes discovering the Principles of Food Preservation in this virtual kitchen:
CLICK HERE or click on the image below to access.
THERE ARE 4 MAIN PRINCIPLES OF PRESERVATION
1. WATER/ MOISTURE AVAILABILITY
2. TEMPERATURE
3. PH LEVEL
4. OXYGEN LEVEL
2. TEMPERATURE
3. PH LEVEL
4. OXYGEN LEVEL
These principles can be separated into two categories; Intrinsic and Extrinsic.
INTRINSIC:
WATER/ MOISTURE AVAILABILITY: Water is the most critical factor for life. By reducing the water present it will inhibit an organisms growth.
PH LEVEL: Organic acids may be naturally produced by fermentation in foods. Majority of microbes wont tolerate a pH of less then 4.2, and as the pH decreases the heat required for sterilisation can be reduced.
EXTRINSIC:
TEMPERATURE: Microorganisms grow of produce toxins in specific temperature ranes, thus the appropriate high or low temperatures are used. Most bacteria are killed by boiling but spores aren't destroyed until they are exposed to 121*c wet heat for 15min. Freezing or removing any free water at -10*c may kill some but not all microorganisms, and refrigeration at 5*c retards but doesn't stop microbial growth.
OXYGEN LEVEL: Most organisms need oxygen to grow, they are placed into two categories; aerobic and anaerobic. For control of aerobic microorganisms air must be removed or excluded and for control of anaerobic microorganisms air must be added. Modified Atmosphere Packaging was developed for this principle.
WATER/ MOISTURE AVAILABILITY: Water is the most critical factor for life. By reducing the water present it will inhibit an organisms growth.
PH LEVEL: Organic acids may be naturally produced by fermentation in foods. Majority of microbes wont tolerate a pH of less then 4.2, and as the pH decreases the heat required for sterilisation can be reduced.
EXTRINSIC:
TEMPERATURE: Microorganisms grow of produce toxins in specific temperature ranes, thus the appropriate high or low temperatures are used. Most bacteria are killed by boiling but spores aren't destroyed until they are exposed to 121*c wet heat for 15min. Freezing or removing any free water at -10*c may kill some but not all microorganisms, and refrigeration at 5*c retards but doesn't stop microbial growth.
OXYGEN LEVEL: Most organisms need oxygen to grow, they are placed into two categories; aerobic and anaerobic. For control of aerobic microorganisms air must be removed or excluded and for control of anaerobic microorganisms air must be added. Modified Atmosphere Packaging was developed for this principle.