Unit 6: Food Processing

Question 1

Food Processing

Answer 1

o Any Operation Carries out on raw food is called a process, which results in a processed food product

Question 2

Reasons for food processing (5)

Answer 2

 Preservation
• Extending shelf life
 To Make Food Edible
 To enhance nutritional quality of food
 To make food more convenient to consume
 Reduction in wastage causing price reduction

Question 3

Principles of Food Preservation and how they help (5)

Answer 3

o Asepsis
 Means keeping microbes out
• Ex: packaging milk

o Slowing growth of microbes
 Microbes need certain level of water activity, pH, and temperature, substrate, oxygen levels etc. to multiply
 If one of the conditions is changed It can extend the shelf life

o Inhibits the growth of microbes
 Microorganisms require certain conditions to grow the conditions can be modified to inhibit certain microbes
• Ex: freezing because takes away the water not allowing for it to grow
• Ex: Drying fruit

o Killing the microorganisms
 Ex: canning

o Controlling chemical reactions in foods
 Food colour, texture, or flavor can change over time due to chemical reactions
 Can remove these reactions by removing one of the reactants

Question 4

Food Preservation Methods (9)

Answer 4

 Pasteurization

o Canning

o Sterilization

o Blanching

o Dehydration

o Refrigeration

o Freezing

o Changing the pH of food

o Preservation by reducing water activity of the food

Question 5

Pasteurization

Answer 5

• Application of heat to food product in order to destroy pathogenic microorganisms, to inactivate spoilage-causing enzymes and to reduce or destroy spoilage in microbes
• Higher the temp the shorter the time needed
• Milk pasteurization can be achieved by low temperature for a long time at 63C for 30 min
o or by high temperature short time treatment at 73C for 15 sec or even higher at 94C for 0.1 sec

Question 6

Canning

Answer 6

 Destroy almost all microbes such that only 1 in a million cans have a microbial cell/spores
 High acid foods <4.6 can be canned at 100C
 Low acid foods pH >4.6 are canned above 116C

Question 7

Sterilization

Answer 7

 Killing all microorganisms in the food is termed as sterilization

also commercial sterilization
 Aims to reduce microbial population to 10-6 cells/spores per ml
 Ex is ultra high temperature milk (UHT)

Question 8

Blanching

Answer 8

 Dipping vegetables in boiling water followed by cooling in cold water to stop cooking
 Inactivates enzymes

Question 9

Dehydration and the 5 types

Answer 9

 Removal of water prevents. Microbial growth

 Sun drying, plate drying, drum drying, spray drying, freeze drying

Question 10

Refrigeration

Answer 10

 Cooling food to above 0C to 4C to slow down microbial growth
 Prevents spoilage
 45% of all fruit and. Vege are wasted
 Fridges reduce food wasted

Question 11

Freezing

Answer 11

 Cooling below 0C to freeze water in food
 Halts microbial growth
 Smaller the ice crystals the better the texture

Question 12

Changing PH of Food

directly and indirectly

Answer 12

 Directly
• Addition of acids such as viniger, citric acid, tartic acid; ex; pickles
 Indirectly
• Lower by fermenting bacteria that produce acid in the food
• Ex: yougart add lactic acid lowers the milk pH

Question 13

Preservation by reducing water activity of the food

Answer 13

 Sugar is used in jam or jelly making

 Table salt reduce water activity ex dehydrated or smoked fish

Question 14

Irradiation

Answer 14

o Called cold pasteurization and is exposing food to ionizing radiation such as gamma rays, electron beams, x-rays etc.
o High speed or/ and high wave destroy the biomolecules

Question 15

reason for packaging

Answer 15

• branding,
• labeling information
• preventing physical damage to the food,
• enabling shipping,
• preventing chemical deterioration,
• biological spoilage
• pathogenic contamination,

Question 16

Canada Food Inspection Agency classification of chemicals in food to preserve

Answer 16

• Class 1
o Curing preservatives

• Class 2
o Antibacterial

• Class 3
o Antifungal and antumycotic

• Class 4
o Antioxidants

Question 17

Canada Food Inspection Agency classification of chemicals in food to preserve

Answer 17

• Class 1
o Curing preservatives

• Class 2
o Antibacterial

• Class 3
o Antifungal and antumycotic

• Class 4
o Antioxidants

Question 18

Nitrates and nitrites use

Answer 18

 Effective in killing pathogenic microbes, maintain the colour of meat, and preventing rancidity

 Can create nitrosamines which causes cancer

 WHO declared highly processed meat is linked with cancer