Lecture 5

Question 1

Containment required for Risk group 1

Answer 1

Good industrial large scale practices(image gilespy bowler)

Question 2

Containment required for Risk group 2

Answer 2

Level 1 containment

Question 3

Containment required for Risk group 3

Answer 3

Level 2 containment

Question 4

Containment required for Risk group 4

Answer 4

Level 3 containment

Question 5

What risk group is: Low individual and community risk. A microorganism that is unlikely to cause human disease or animal disease of veterinary importance

Answer 5

Risk Group 1 - open lab

Question 6

What risk group is: Moderate individual risk, limted community risk. Can cause human disease but is unlikely to be a serious hazard to laboratory workers. Eg: Salmonella food poisoning.

Answer 6

Risk group 2 - aseptic lab practises

Question 7

What risk group is: High individual risk, low community risk. A pathogen that usually causes serious human disease, but does not orinarily spread from one infected individual to another. Prophylaxis and treatment may be available

Answer 7

Risk group 3 - fume hood practises

Question 8

What risk group is: High individual and community risk. A pathogen that usually causes serious human or animal disease and may be readily transmitted from one individual to another. No effective prophylaxis or treatment is available eg. Ebola virus

Answer 8

Risk group 4 - space suit y’all

Question 9

What is prophylaxis

Answer 9

Measure taken to prevent the occurrence of disease - e.g. disinfection, immunization

Question 10

What are 2 varieties of methods used to control microbial growth?

Answer 10

Physical methods and Chemical agents

Question 11

What are 6 types of physical methods used to control microbial growth?

Answer 11

DHORFL

1. Desiccation
2. Heat
3. Osmotic Pressure
4. Radiation
5. Filtration
6. Low Heat

Question 12

Define Sterilization

Answer 12

The destruction of all forms of microbial life, including most resistant forms.

Question 13

What is the most common method used for sterilization?

Answer 13

Heating

Question 14

Term for heat treatment when food is subjected to only enough heat to destroy the endospores of Clostridium botulinum, which can produce deadly toxins.

Answer 14

commercial sterilization

Question 15

Define Disinfection

Answer 15

Control directed at destroying harmful microorganisms . It usually refers to the destruction of vegetative (non-endospore forming) pathogens.

Question 16

True or False - Disinfection is the use of a chemical (a disinfectant) to treat an inert surface or substance.

Answer 16

True

Question 17

When this treatment is directed at a living tissue, it is called ___________and the chemical is then called an ______________.

Answer 17

antisepsis, antiseptic.

Question 18

When your skin is swabbed with alcohol before a jab what is that process called?

Answer 18

Degerming - removing not killing

Question 19

Referring to disinfection and antisepsis when it comes to restaurant glassware, china, and tableware are subjected to ______

Answer 19

Sanitization

Question 20

Names of treatments that cause the outright death of microbes have the suffix _____meaning kill

Answer 20

cide

Question 21

What is an endospore?

Answer 21

Type of spore formed intracellularly by the parent cell or hyph

Question 22

What would fungicide do?

Answer 22

Kill fungi

Question 23

What would virucide do?

Answer 23

inactivate viruses

Question 24

What would biocide and germicide do?

Answer 24

Kill microorganisms

Question 25

The suffix -stat or -statis, means to

Answer 25

stop or to steady

Question 26

Bateriostatis

Answer 26

Temporarily stop growth

Question 27

Sepsis indicates?

Answer 27

bacterial contamination

Question 28

Asepsis is?

Answer 28

absence of signification contamination - like aseptic techniques

Question 29

If the death curve is plotted logarithmically, the death rate is

Answer 29

constant

Question 30

What are 4 factors influence the effectiveness of antimicrobial treatments?

Answer 30

1. The number of microbes 2. Environmental influences 3. Time of exposure 4. Microbial characteristics

Question 31

What are two of the earliest techniques used for microbial control?

Answer 31

Drying (desiccation) and salting (osmotic pressure)

Question 32

Define Thermal death point (TDP)

Answer 32

the lowest temperature at which all microorganisms in a liquid suspension will be killed in 10 minutes.

Question 33

Define Thermal death time (TDT)

Answer 33

the minimal length of time for all bacteria in a liquid culture to be killed at a given temperature.

Question 34

Define Decimal Reduction time (DRT or D value)

Answer 34

DRT is the time, in minutes, in which 90% of a population of a given bacteria at a given temperature will be killed.

Question 35

Autoclaving like boiling is a moist heat microbial control what 2 factors are involved in this method of control?

Answer 35

Steam and pressure

Question 36

What are 2 ways to check that an autoclave sterilization has worked?

Answer 36

Colour changing tape, and endospore impregnated strips

Question 37

Thermoduric refers to …..

Answer 37

Heat resistant bacteria - duric - durable

Question 38

HTST pasteurization heat and time is

Answer 38

135C, 1-2 sec

Question 39

UHT milk pasteurization heat and time is

Answer 39

72C- 85C for 15sec

Question 40

Dry Heat kills by _________ effects.

Answer 40

oxidation

Question 41

Simplest form of dry heat sterilization is

Answer 41

direct flaming incineration

Question 42

During dry heat sterilisation, items are place in a _______ and set to _____C for nearly _____ hours

Answer 42

oven, 170C, 2

Question 43

Why is slow freezing more harmful to bacteria?

Answer 43

the ice crystals that form disrupt the cellular and molecular structure of the bacteria.

Question 44

What is Lyphilization

Answer 44

Freeze-Drying - quickly and water removed via high vacuum

Question 45

What is the temperature range used for Lyphilization ?

Answer 45

-54C - 72C

Question 46

Can organisms that have undergone lyphilization be revived at any time by hydration with a suitable liquid nutrient medium.

Answer 46

yes

Question 47

In the absence of water, a condition known as __________ where microorganisms cannot grow or reproduce but can remain viable for years.

Answer 47

desiccation

Question 48

The use of high concentrations of salts and sugars to preserve food is based on the effects of ___

Answer 48

osmotic pressure

Question 49

What are two types of radiation?

Answer 49

Ionizing and Non-Ionizing

Question 50

The vegetative stage in organisms life cycle where______

Answer 50

nutrition and growth predominate as opposed to sexual reproduction or dormancy.

Question 51

The three bacteria used in the use-dilution test are?

Answer 51

Salmonella choleraensuis, Staphylococcus aureus and Pseudomonas aeruginosa

Question 52

What are two types of Evaluating Disinfectant 

Answer 52

Use-dilution test andThe disk-diffusion test

Question 53

In the disk diffusion test - Disks containing antibiotics are commercially available and used to determine what?

Answer 53

microbial susceptibility to antibiotics.

Question 54

Alcohols effectively kill bacteria and fungi but not

Answer 54

endospores and non-enveloped viruses.

Question 55

Two of the most commonly used alcohols are

Answer 55

ethanol and isopropanol

Question 56

The recommended optimum concentration of alcohol is 70%, but concentrations between 60-95% seem to kill as fast. Why is pure ethanol less effective than aqueous solution? (ethanol mixed with water)

Answer 56

because denaturation requires water

Question 57

Define Fomites

Answer 57

Inanimate objects that may be contaminated with infectious organisms and serve in their transmission.

Question 58

Rodac agar plates are when Agar fills the entire dish to produce a ______ surface, which is then______

Answer 58

Convex, pressed against the surface to be sampled

Question 59

Swab-rinse technique is where?

Answer 59

A sterile cotton swab is moistened with a buffer or other solution and rubbed over the surface to be sampled