Introduction Lecture

Question 1

The good microorganisms

Answer 1

Add them to foods to they are there naturally

Used for food fermentation ?

Question 2

Examples of good microorganism

Answer 2

Cheese
Yogurt 
Sour cream 
Bread
Salami
Pickles

Question 3

What is the goal of food fermentation ?

Answer 3

Preservation and/or creating unique flavors and textures

Question 4

The bad microorganisms

Answer 4

Change foods and cause them to do bad or spoil

Affect aroma, texture and appearance of food

Question 5

Examples of bad microorganism

Answer 5

Discolored,mushy or fuzzy vegetables
Sour milk
Slimy, putrid meat

Question 6

The ugly microorganism

Answer 6

Pathogenic, cause illness ranging from mild to life threatening

May NOT affect sensory characteristics of the food

Question 7

Examples of microorganism

Answer 7

Salmonella

E coli 0157: H7

Question 8

Common side effects of ugly microorganism

Answer 8

GI symptoms
Diarrhea
Nausea
Vomiting

Question 9

What is incubation period

Answer 9

From the time you are infected to the time that you show symptoms

Question 10

Challenges with pathogens that have longer incubation period

Answer 10

You dont remember where and how you got it from

Collecting samples

Question 11

Factors affecting microbial growth in foods

Answer 11

Intrinsic factors ( food environment

Extrinsic factors

Question 12

What are intrinsic factors

Answer 12

Inherent parameter of foods that affect their microbiology

Question 13

What are extrinsic factors

Answer 13

Properties of the storage environment that affect their microbiology

Question 14

Examples of intrinsic factors

Answer 14

General nutrient 
Water activity 
PH
Oxidation reduction potential 
Growth inhibitors in foods

Question 15

What are general nutrient in intrinsic factor ?

Answer 15

Water
Nitrogen 
Carbon for growth 
Carbon for energy
Oxygen 
Phosphorous , potassium, sulfur 
Cofactors, vitamins , trace minerals , micronutrient

Question 16

Water activity

Answer 16

Ratio of vapor pressure of water in sample to vapor pressure of pure water at the same temperature

Question 17

Formula for water activity

Answer 17

Aw=Ps/Pw

Question 18

Water activity is always

Answer 18

Less than 1

Question 19

Water activity measure free water or bound water

Answer 19

Free water

Question 20

What is formula for relative humidity

Answer 20

RH=aw X 100

Question 21

Water activity for many bacteria

Answer 21

0.91

Question 22

Processing to reduce water activity

Answer 22

Drying-less than 10-15% moisture means no growth
Additives- solutes
Salt, sugar, alcohol ( glycerol)
Compound blending- both in food manufacturing and recipe development

Question 23

How does adding solutes is related to water activity

Answer 23

When you add solutes they bind to free water and will be unavailable so it lowers the water activity

Question 24

Classification of foods by acidity

Answer 24

Acid foods 4.5 or less

Low acid : above 4.5

Question 25

What are foodborne microorganisms?

Answer 25

Molds Bacteria Parasites Viruses

Question 26

Molds

Answer 26

Multicellular organisms

Question 27

Bacteria

Answer 27

Single celled organisms that live independently

Question 28

Parasites

Answer 28

Intestinal worms or microscopic Protozoa that live in a host animal or human

Question 29

Viruses

Answer 29

Small particles that live and can only replicate in a host

Question 30

Where do foodborne pathogens live

Answer 30

Most are residents of intestinal tracts of human and animals Some common in soils

Question 31

Pathogens that live in intestinal tract of humans and animals

Answer 31

``` Salmonella Ecoli O157:H7 Shigella Campylobacter Viruses and parasites ```

Question 32

Foodborne pathogens that live in soils

Answer 32

Listeria monocytogenes Bacillus cereus Clostridium botulinum

Question 33

What are Extrinsic Factors?

Answer 33

``` Temperature Relative humidity Atmosphere of storage Physical state Additives ```

Question 34

Most important Extrinsic factor?

Answer 34

Temperature

Question 35

Low temperature

Answer 35

Prolong generation time and extend shelf life

Question 36

Hot temperature

Answer 36

Prevent microbial growth

Question 37

High temperature

Answer 37

Kill microorganisms and spores

Question 38

Goal of MAP

Answer 38

Slow respiration rates Reduce microbiological growth retard enzymatic spoilage

Question 39

How to achieve MAP

Answer 39

Reduce oxygen content Increase carbon dioxide Increase Nitrogen

Question 40

2 methods of MAP

Answer 40

Vaccum packaging Gas packaging

Question 41

What does vacuum packaging do?

Answer 41

Result in headspace O2 of less than 1% and CO2 levels of 10-20% depending on tissue or microbial respiration

Question 42

What does Gas packaging do?

Answer 42

Extension of vacuum packaging | Replace the removal of air with another gases-usually N2 and Co2 or O

Question 43

Name some Edible Antimicrobial films

Answer 43

Zein Bacteriocins Nisin

Question 44

Nisin is particularly good for inhibition of

Answer 44

Listeria