Download Foods and Nutrition 12: Food Preservation Name:

Foods and Nutrition 12: Food Preservation
Name:
Fresh * Frozen* Freeze Dried *Individaully Quick Frozen* Smoked *Dehydrated* Salted* Canned* Sugar
As a class, discuss the questions and fill in the answers.
1. Why does food deteriorate over time?
2. List the 6 methods of food preservation that were used by ancient people, and still used today.
3. In the days before refrigeration, how was fresh meat preserved?
4. Microbes are very sensitive to ____________________.
5. Which foods are microbes used to produce?
6. How can the temperature of food be brought above boiling temperature?
7. Most food preservation methods remove _____________________________________ from the food.
8. When we refrigerate food, what happens to the microbes?
Foods and Nutrition 12: Food Preservation
Name:
Complete the chart by filling in the last column. Also, highlight any nutrient losses/health concerns that occur due to the
food preservation method.
Method
Advantages
Disadvantages
Food and Equipment
Example
Drying (e.g. freeze-drying,
spray-drying, sun-drying,
oven drying, food
dehydrator)
Produces concentrated
form of food.
Can cause loss of some
nutrients, particularly
thiamin & vitamin C.
Food examples:
Inhibits microbial growth &
autolytic enzymes.
Retains most nutrients.
Smoking
Refrigeration
Preserve partly by drying,
partly by incorporation of
substances from smoke
and/or chemical
nitrates/nitrites , which are
used to preserve the pink
colour.
Eating a lot of smoked foods
has been linked with some
cancers in some parts of the
world – the evidence is not
conclusive whether the
carcinogen is the smoke, or
the nitrates, or some other
factor.
Food examples:
Slows microbial
multiplication.
Slow loss of some nutrients
with time
Food examples:
Slows autolysis by enzymes
Freezing
Sulphur dioxide is
sometimes added to dried
Equipment:
fruits to retain vitamin C, but
some individuals are
sensitive to this substance.
Prevents microbial growth
by low temperature &
unavailability of water.
Equipment:
Equipment:
Blanching of vegetables prior Food examples:
to freezing causes loss of
some B-Group vitamins and
vitamin C.
Generally good retention of
Unintended thawing due to Equipment:
nutrients.
variations in the freezer
temperature can reduce
product quality = foods can
get freezer burn, deteriorate
in quality
Foods and Nutrition 12: Food Preservation
Adding salt or sugar
Makes water unavailable
for microbial growth.
Name:
Increases salt and sugar
content of food.
Food examples:
Loss of heat-sensitive
nutrients.
Food Examples:
Water-soluble nutrients can
be lost into liquid in can.
Food Examples:
Process does not destroy
nutrients.
High heat processing (e.g.
pasteurisation)
Inactivates autolytic
enzymes
Destroys microorganisms.
Canning (involves high heat
processing)
Destroys microorganisms &
autolytic enzymes.
Equipment:
Chemical preservatives
Prevent microbial growth
No loss of nutrient.
Ionizing radiation
Some people are sensitive to See question C
some chemical
preservatives.
Sterilizes foods (such as
Longer shelf life of fresh
spices) whose flavour
foods can lead to greater
would change with heating. nutrient losses than if eaten
sooner after harvesting.
Inhibits sprouting potatoes
Extends shelf life of
strawberries and
mushrooms
Food Examples:
Foods and Nutrition 12: Food Preservation
Name:
A.) Chemical Preservatives
Look at the food items in the pantry in the classroom and at home. Can you find ingredients that are chemical
preservatives? Use the additive handouts to discover the function of the ingredient, and its safety status.
Food item
Chemical preservative
Function of the
preservative
Safety status
Look at the “Additives to Avoid” – List ten types of foods that are most likely to contain these most concerning food
additives.
_
_
_
_
_
_
_
_
_
_
Stability of nutrients in food: Vitamins
can be altered during processing conditions such as exposure to
high heat, air, light, water. Once altered, it won’t be able to serve its function in the body. Highlight the vitamins and
the conditions under which the vitamins can be damaged.
Nutrient
Stability Characteristics
Vitamin A
Quite stable during processing and cooking
Vitamin D
Very stable to heat but sensitive to exposure to air and
light.
Vitamin E
Relatively stable except at deep frying temperatures
Vitamin K
Stable in cooking but sensitive to light.
Foods and Nutrition 12: Food Preservation
Name:
Thiamin
Quite unstable to heat and alkaline conditions. Lost
during refining of cereals. Dissolves in cooking water.
Riboflavin
Very sensitive to light: 50% lost from milk left in sun for
2 hours.
Relatively stable to most home cooking methods (unless
bicarbonate of soda added).
Niacin
Stable to most processing but leaches into cooking
water.
Vitamin B-6
Moderate retention during most processing.
Vitamin B-12
Moderate retention, but losses occur when heated
under acid and alkaline conditions.
Folic acid
Large losses can occur during cooking. Presence of
copper aids
destruction.
Pantothenic acid
Relatively stable during most home processing.
Biotin
Good retention during most home processing.
Vitamin C
Unstable. Losses occur from exposure to air, light, heat
and copper. Also dissolves in cooking water.
1.) Milk is pasteurized and then typically packaged in opaque (not clear) containers. Why? (2)
2.) Why is fresh food “healthier” than processed, preserved food? (2)
3.) Why does our food supply and typical eating habits rely on processed and preserved foods when they aren’t the
most nutritious choice? (4)
Foods and Nutrition 12: Food Preservation
Name:
Read the article Food That Lasts Forever and answer the following questions.
4.) How does the article propose that food preservation techniques will change the way we shop for and use food?
5.) Describe the “indestructible sandwich”. Why was this item developed?
6.) What is the life expectancy of a can of SPAM compared with its actual expiration date? Why is there such a large
difference between these numbers?
7.) How is the old method of sterilization different from the new HPP (high pressure processing)? What benefits are
there for the consumer?
8.) In what situations are processed, shelf stable (no refrigeration required) foods especially important?
9.) According to the food science expert quoted in the article, how much food is lost to rot and decay in the world? (2)
Foods and Nutrition 12: Food Preservation
Reasons to Preserve Food:
Canning Notes and Diagram
Name: