Ch. 16 - Food Preservation
what are (6) examples of preservatives?
-acids -sugar -salt -smoke -vinegar -chemicals
why is concentration (3 reasons) not a method of preservation?
-adequate water remains for microbial growth -additional preservation methods are needed to prevent spoilage -possible flavor and nutrient changes during heat treatment (cooked flavor formation, browning, or thickening/gel formation)
what quality changes can occur from dehydration?
-color, flavor, or texture changes -enzyme activity -non-enzymatic browning -oxidation
what is the purpose (4 reasons) of pasteurization?
-destroy pathogens -reduce bacterial count -inactivate enzymes -extend shelf life
what is the purpose (4 reasons) of heat preservation?
-eliminate pathogens that cause disease -eliminate or reduce spoilage microorganisms -extend shelf life -improve palatability
what are the four techniques of food preservation?
-heating -cooling (refrigeration or freezing) -dehydration -concentration
what is the purpose (2 reasons) of blanching?
-inactivate enzymes that would cause deterioration during freezing -kills some bacteria
what are (4) foods treated with pasteurization?
-milk -liquid eggs -fruit juices -beer
what are (6) problems related to ice crystal formation?
-physical damange to tissues (drip loss) -changes in texture and flavor -growth of ice crystals -freezer burn -oxidation -colloidal substance change
what are the four benefits of using irradiation to sterilize food?
-reduces microbial load -kills insects -controls ripening -inhibits sprouting of some vegetables
what are the benefits (3) to foods subjected to high hydrostatic pressure?
-significant decrease in microorganisms -extends shelf-life -minimal effect on sensory and nutritional properties
what is the objective of food preservation? (4 main points)
-slow down or kill bacterial spoilage -minimize chemical and physical degradation -improve palatability of food -provide foods that are safe, nutritious, and have good sensory quality
what are (5) methods of dehydration?
-sun-drying -mechanical drying -drum drying -freeze-drying -spray drying
what is the temperature range for canning and bottling?
241-250 degrees F
define commercial sterility
all pathogenic, toxin-forming and spoilage organisms are killed
what are the severe heat treatment methods?
canning and bottling
what are the benefits of dehydration? (2)
decrease in microbial growth and increased shelf life
true or false: all foods are approved for irradiation by the FDA
false: approved by FDA for use with SPECIFIC foods and DESIGNATED dosages
true or false: bacteria is dormant during freezing and remain dormant when the food is thawed
false: bacteria are dormant during freezing but can grow when food is thawed again
true or false: concentration is a method of preservation
false: concentration is not a method of preservation
true or false: irradiation uses heat to sterilize the food
false: does not add heat to food
true or false: blanching produces a completely sterile product
false: does not produce a sterile product; freezing is needed to extend shelf life
true or false: high hydrostatic pressure sterilizes food
false: does not sterilize food
true or false: some radiation residue remains in food after irradiation is used
false: no radiation residue remains in food
true or false: refrigeration is suitable for both short-term and long-term storage
false: only suitable for short-term storage
true or false: processing temperatures and times are the same for all foods to kill pathogenic microorganisms in the food
false: processing temperatures and times are dependent on the heat needed to kill pathogenic microorganisms in that particular food
define canning/bottling
food placed in sealed can/bottle and heated at high temperatures
what is irradiation?
food treated with gamma rays
what are some common products that are concentrated?
fruit/vegetable juices, milk products, soups, sugar, and syrups
describe the process of blanching
fruits and vegetables are dipped in boiling water for 1-3 minutes prior to freezing
what is the benefit of concentration?
more economical (costs less) for transportation and shipping
what is the average shelf-life of canned/bottled goods?
more than 6 months
what is high hydrostatic pressure?
non-thermal pasteurization method for food processing
what are the mild heat treatment methods?
pasteurization and blanching
what is dehydration?
preservation of foods be the removal of water
what is required to slow the growth of surviving bacteria that could cause spoilage?
refrigeration
what is concentration?
removal of water from food to reduce weight and bulk
what are common problems (3) with refrigeration as a long-term preservation method?
spoilage, cross-contamination, and temperature (damage to some fruits/vegetables)
true or false: canned foods are stable at room temperature
true
true or false: food is sterilized using irradiation
true
true or false: irradiated foods must be labeled
true
true or false: pasteurization does not produce a sterile product
true: some non-pathogenic bacteria survive
what are added preservatives used for?
used with preservation methods to further slow the growth of microorganisms and extend the shelf life of the food
why is freezing a good method for long-term storage?
water is unavailable for bacterial growth due to the formation of ice crystals
what is refrigeration?
when foods are held at temperatures below 45 degrees F that slow bacterial growth
