Topic 2: Part C

Question 1

Thermal processing

Answer 1

important heat treatment methods used in processing include sterilization, pasteurization, blanching, and canning

Question 2

Thermal processing can cause a loss of..

Answer 2

heat sensitive nutrients

Question 3

Sterilization

Answer 3

complete distraction of microorganisms. exposed to wet heat for 15 min at 121 C.

Question 4

In commercials sterile foods all ..

Answer 4

pathogenic and toxin producing organisms as well as spoilage microorganisms are destroyed. some tea resistance bacterial spores may remain however very likely to multiply.

Question 5

Commercially sterile foods have a shelf life of..

Answer 5

2 years

Question 6

Pasteurization

Answer 6

heating foods/liquids to a specified high temp (80-90C) for a short time kills most disease causing microbes and their spores

Question 7

Pasteurization food is not sterile so it much be..

Answer 7

refrigerated or preserved by other means

Question 8

Heating foods to a specified high temp for a short time ..

Answer 8

kills bacteria

Question 9

Pasteurized foods are not

Answer 9

sterile so it but be refrigerated or preserved

Question 10

Pasteurization of milk and fruit juices results in ..

Answer 10

considerable loss of vitamin C

Question 11

Flash pasteurization

Answer 11

uses high temp for short period of time (3-15seconds). products cool quickly then packaged. allows the product to be safely stored unrefrigerated for extended periods of time (drink boxes)

Question 12

Flash pasteurization also called ..

Answer 12

high temp short time (HTST) pasteurization or ultra high temp (UHT)

Question 13

Canning

Answer 13

heating foods to 110C for a number of minutes. kills most harmful or spoilage causing microbes and their spores, however canned foods aren’t sterile.

Question 14

Heat and canning

Answer 14

must be controlled to kill harmful microbes without damage to nutrient quality. heat also destroys enzymes that cause deterioration of food.

Question 15

Water soluble foods may be lost when food..

Answer 15

is canned in water, especially if the water is discarded before the food is consumed

Question 16

Most common canned foods are

Answer 16

veggies, fruits and meats

Question 17

Traditional canning

Answer 17

2 step process involves packing food into containers which are then sealed and heated to destroy all microorganisms.

Question 18

Home canning

Answer 18

1. boiling water processing
2. pressure cooling
   - method is dependent on pH of food to be canned

Question 19

Boiling water processing used for..

Answer 19

fruits and veggies with pH below 4.6

Question 20

Boiling water processing

Answer 20

jars are placed in canner filled with enough water to come 2 inches up the outside of the jar. water is then heated and jars are boiled. time needed depends on type of food being canned.

Question 21

Pressure canning used for..

Answer 21

meats, fish, poultry, veggies with pH higher than 4.6

Question 22

Pressure canning

Answer 22

jars are placed in a pressure canner with water and then heated. time needed depends on type of food being canned.

Question 23

Low canning temp and improper seals may allow growth ..

Answer 23

of Clostridium botulinum which causes the deadly botulism poisoning

Question 24

Canning cannot survive in acidic environment so ..

Answer 24

boiling is sufficient to process foods with a low pH

Question 25

Food with high pH need to be canned under..

Answer 25

pressure so that the temp can reach about 116C to kill C. Botulinum spores

Question 26

Cooling- refrigeration

Answer 26

involves cooling of food temp to levels that slow down growth of micro organism and food spoilage. excellent for painting sensory quality and nutritional value.

Question 27

Refrigeration does not prevent the..

Answer 27

growth of spores. Lisertia can grow in these temps.

Question 28

Ideal refrigeration temp

Answer 28

0 to 4 C

Question 29

Ideal freezing temp

Answer 29

-18 to -22 C

Question 30

Freezing

Answer 30

involves cooling of foods to temp levels that prevent growth of microbes making water unavailable to microbes. enzymes can still be active and spoil food. when meat is thawed some vitamins can be lost in drippings

Question 31

Some oxygen is still available in freezing and..

Answer 31

food cannot be froze indefinitely

Question 32

Freezer burn

Answer 32

water loss in food by sublimation. occurs when food is wrongly packaged/frozen too long (1 year+). the food develops white/greyish colour patches and when thawed may be sponge like.