INTRODUCTION AND HISTORY OF FOOD MICROBIOLOGY

Question 1

Microbial impact on foods

Positive effects such as

Answer 1

1.Food Fermentaion-flavors 2.Probiotic bacteria 3.Bacteriocins

Question 2

Microbial impact on foods

Negative effects such as

Answer 2

1. Spoilage

2. Lose of shelf-life 3.Foodborne pathogens

Question 3

Cell division occurs on a

Answer 3

on a single plane (bacilli), muliple planes (cocci)

Question 4

Listeria monocytogenes, Escherichia coli O157:H7, Salmonella, Shigella, Clostridium, Yersinia, Bacillus cereus,

Answer 4

Bacilli

Question 5

Staphylococcus aureus

Answer 5

Cocci

Question 6

Vibrio

Answer 6

Vibrio vulniicus,

Vibrio parahemolyicus

Question 7

Campylobacter

Answer 7

Spirillum

Question 8

What kinds of Bacterial Shapes ?

Answer 8

1. Bacilli
2. Cocci
3. Vibrio
4. Spirillum

Question 9

what Structures External to the Cell Wall of Bacteria?

Answer 9

Flagella (H anigen)
Pili
Axial Filaments

Question 10

Thin appendage; primary funcion moility

Answer 10

Flagella (H anigen)

Question 11

Flagella Bacteria can be:

Answer 11

monotrichous means single

peritrichous means many around cell

Question 12

✅❌

cocci are rarely moile

Answer 12

✅

Question 13

✅❌

Generally only bacilli and vibrio posses flagella

Answer 13

✅

Question 14

what is the Pili ?

Answer 14

• Short, thin hollow hair like structures, -primarily on Gram negaive
• Consist of a protein

Question 15

✅❌

Pili have funcion regarding moility

Answer 15

❌ No .

common pili believed to have a role in the attachment to surfaces

Question 16

Axial Filaments Found only on

Answer 16

spirochetes

Question 17

Axial Filaments cause

Answer 17

entire cell to rotate for moility

Question 18

Anchored at one end of cell, like flagella (structurally), but wrapped around
cell

Answer 18

Axial Filaments

Question 19

What are Structures Internal to the Cell Wall

of Bacteria?

Answer 19

Ribosome -Nucleoid
Storage granules (cytoplasm)
Single membrane bound vesicles (Plasma membrane )
Cytoplasmic membrane

Question 20

Ribosome of bacteria is Located in the

Answer 20

cytoplasm

Question 21

Gives bacteria a granular appearance in electron micrographs

Answer 21

Ribosome

Question 22

Ribosome Function

Answer 22

Translates mRNA into protein.

Question 23

Location of the bacterial genetic DNA

Answer 23

Nucleoid

Question 24

Storage granules Storage of nutrients in the

Answer 24

cytoplasm

Question 25

Storage granules in bacteria is Composed of

Answer 25

glycogen, sulfur, or polyphosphates

Question 26

Caused by increased osmoic condiions

Answer 26

Single membrane bound vesicles

Question 27

Rapid lose of water causes

Answer 27

the Plasma membrane to pull away from | cell wall which allows the membrane to have a smoother appearance.

Question 28

Cytoplasmic membrane Made of

Answer 28

phospholipids with proteins embedded

Question 29

Cytoplasmic membrane function

Answer 29

It maintains the selecive permeability of the cell ( gate for in and out things)

Question 30

During cell division the chromosome is linked to cell membrane at a site called

Answer 30

mesosomes

Question 31

Semi-rigid structure which gives cell its’ shape

Answer 31

Cell Wall

Question 32

what is the Cell Wall | Funcions ?

Answer 32

Functions to protect the cell from Osmotic pressure and serves as an attachment point for flagella

Question 33

peptidoglycan is only found in the

Answer 33

cell walls of bacteria

Question 34

Cell Wall Contains porin for what?

Answer 34

To transport of low molecular weight substances.

Question 35

What is the diference between gram positive bacteria and gram negative bacteria?

Answer 35

Gram positive bacteria have a thick peptidoglycan layer and no outer lipid membrane, whilst Gram negative bacteria have a thin peptidoglycan layer and have an outer lipid membrane

Question 36

have antigenic properies and can be used to identify Gram posiive bacteria by serological tests

Answer 36

Teichoic acids

Question 37

endotoxin in Gram Negative

Answer 37

Lipopolysaccharide (LPS)

Question 38

Outer membrane of Gram Negative is composed of

Answer 38

phospholipids and lipopolysaccharide

Question 39

Lipopolysaccharide (LPS) determines

Answer 39

determines antigenicity (O antigen) and pathogenicity

Question 40

Gram Negative | Consists of an

Answer 40

outer cell membrane and the periplasmic space

Question 41

Periplasmic space in Gram Negative | contains

Answer 41

lipoprotein and peptidoglycan layer

Question 42

✅❌ Fruits and Vegetables have natural micro-flora on their surface and can become contaminated with foodborne pathogens

Answer 42

✅

Question 43

Examples of natural micro-lora on their surface

Answer 43

Bell peppers > Listeria Corn > Enterococcus Garlic > Leuconostoc Cucumber Lactobacillus Grapes > Leuconostoc

Question 44

Examples about Fruits and Vegetables can become contaminated with foodborne pathogens

Answer 44

``` Sprouts > Salmonella Letuce > Listeria monocytogenes Apples > E. coli O157:H7 Cantaloupe > Salmonella Cabbage > Listeria monocytogenes ```

Question 45

Air can contain Molds,viruses and bacteria | Levels in the air depend on:

Answer 45

1. Humidity ( high more Microorganisms) 2. Size and level of dust paricles 3. Temperature (opimum and minimum) 4. Resistance to drying

Question 46

is rich source of microorganisms

Answer 46

Soil

Question 47

Bacteria spore formers

Answer 47

Clostridium, Bacillus

Question 48

fungal spores produced by

Answer 48

Aspergillus

Question 49

(soil speciic)

Answer 49

Enterobacter

Question 50

Water can be contaminated with

Answer 50

Pseudomonas, Klebsiella, Vibrio, E. coli

Question 51

Wash water (municipal water) may contain

Answer 51

103 psychrotroph /ml | are known contaminates of dairy product

Question 52

Bacteria that are found in the intesinal tract

Answer 52

E. coli

Question 53

Animal hides, skin & hair contain

Answer 53

Staphylococcus

Question 54

How can Shellish bed contaminaion ?

Answer 54

1. Improperly treated sewage | 2. Pathogens naturally found in waters such as Vibrios

Question 55

life cycle of biofilms

Answer 55

``` 1-reversible atachment 2-Irreversible atachment 3-Early development of biofilm formaion 4-Maturation 5-Dispersion ```

Question 56

Bacterial cells are released from biofilms into the surrounding environment.

Answer 56

Dispersion

Question 57

Maturation the biofilm

Answer 57

the biofilm develops into an organized resistant structure to chemicals and disinfectants.

Question 58

Initial reversible attachment Biofilms formation starts with the

Answer 58

attachment of bacteria to solid surfaces mainly due to van der Waals and electrostaic forces.

Question 59

Irreversible attachment

Answer 59

The biofilm grows through cell division and irreversible atachment with producion of extracellular polymers substance (EPS) .

Question 60

The EPS layer strengthens the structure between bacterial cells and atachment surface.

Answer 60

Early development of biofilm formation

Question 61

what is the Biofilms ?

Answer 61

as a community of bacteria enclosed in a self-produced | exopolysaccharide matrix that adheres to a biotic or abiotic surface.

Question 62

is the physical movement or transfer of harmful | bacteria from one person, object or place to another

Answer 62

Cross contamination

Question 63

Cause miscarriage in pregnant women.

Answer 63

Listeria monocytogenes

Question 64

Thermophilic 🦠bacteria

Answer 64

are those that can grow at high temperatures | which are normally found in hot springs.

Question 65

Psychrotrophic bacteria 🧫

Answer 65

are those that can grow at refrigeraion temperatures and lead to the spoilage of product.