Chap 7 - Control of Microorganisms: Phys and Chem

Question 0

The destruction of all living microbes, spores and viruses.

Answer 0

Sterilization

Question 1

When do sterile objects become contaminated?

Answer 1

When exposed to air and surroundings.

Question 3

Does sanitization sterilize?

Answer 3

No. Sanitation reduces the number of pathogens or discourages their growth

Question 4

Sanitization does what?

Answer 4

Reduces the numbers of pathogens. Lower level of control

Question 4

What happens when microbes are at temperatures above their growth ranges?

Answer 4

Proteins and nucleic acids are destroyed, water is removed.

Question 5

What is one of the most common physical control methods?

Answer 5

Heat

Question 6

What method of heat uses direct flames to kill microbes?

Answer 6

Incineration

Question 7

The minimum temperature to kill a species is considered what?

Answer 7

Thermal death point.

Question 8

Thermal death time is what?

Answer 8

The length of time required to kill a microbial population at a given temperature.

Question 9

Does hot air sterilization take a short time and does it penetrate?

Answer 9

No - it takes a long time and doesn’t penetrate

Question 10

Dry and Moist Heat are applied similarly. (T/F)

Answer 10

False. Dry heat requires more time.

Question 11

Name one tool used for incineration

Answer 11

Bunsen burner

Question 12

Dry heat quickly burns the microbes. (T/F)

Answer 12

False - it slowly burns

Question 13

Dry heat creates a moist environment. (T/F)

Answer 13

False - it creates an arid environment.

Question 14

Dry heat creates an arid internal environment that changes microbial proteins by what?

Answer 14

Oxidation

Question 15

Moist heat can be used to sterilize.

Answer 15

True

Question 17

Boiling water kills all spores and inactivates all viruses.

Answer 17

False.

Question 18

Which penetrates microbes better: dry heat or hot water?

Answer 18

hot water

Question 19

Moist heat kills microbes by doing what?

Answer 19

Denaturing their proteins.

Question 20

Autoclaves use what to kill microbes?

Answer 20

Steam, specifically Pressurized steam.

Question 21

In Autoclaves, _______ increases as _______ increases.

Answer 21

Temperature, Pressure

Question 22

This machine decreases the cycle time and exposure of sensitive materials to steam (creates saturated steam)

Answer 22

The prevaccum autoclave

Question 23

If materials are not suited to the autoclave, what form of sterilization is used?

Answer 23

Fractional sterilization / intermittent sterilization (pg. 203)

Question 24

Pasteurization is a form of _____ heat.

Answer 24

moist

Question 25

What does pasteurization do?

Answer 25

Reduce bacterial populations in food and drink.

Question 26

Why is pasteurization used in food & drink?

Answer 26

It reduces spoilage and disease. Kills pathogens and food spoilage organisms

Question 27

Are bacterial spores affected by pasteurization?

Answer 27

No

Question 28

What is the only method of pasteurization used to sterilize liquid?

Answer 28

Flash pasteurization.

Question 29

In regard to filtration, how are microbes filtered? Viruses?

Answer 29

Pores, 0.2 micrometers which are smaller than most microbes. The average filter would allow viruses to pass through.

Question 30

Can viruses pass through pores?

Answer 30

Yes - they might be able to if they are smaller than 2 micrometers

Question 31

What does HEPA stand for?

Answer 31

High-efficiency particle air (filter)

Question 32

What kind of filter are used in hospitals?

Answer 32

HEPA Filters

Question 33

Can UV Light be used as a Microbial Control path?

Answer 33

Yes. DNA of the cell absorbs the the UV light, causes adjacent thymine molecules to link together, kinking double helix

Question 34

UV light does what to microbial growth?

Answer 34

Remember: Disrupts DNA replications and transcription Disruption in turn reduces population, limits airborne/surface contamination

Question 35

What are the types of radiation that can sterilize materials?

Answer 35

X Rays | Gamma Rays | Ionizing radiation

Question 36

This type of radiation forces electrons out of microbial molecules and is used in food products (pasteurizing dose)

Answer 36

Ionizing radiation

Question 37

Radiation for food is not used for shelf stability. (T/F)

Answer 37

False, it is used. Food is not sterile but removes chances of food born illnesses

Question 38

Bacteriostatic means what?

Answer 38

Slow multiplication of organisms. Anything with "-static" will reduce the numbers or inhibit growth. Others are: microbiostatic, fungistatic

Question 39

This form of preservation removes water necessary for microbes to live. ("where there is water, there is no life")

Answer 39

Drying (used in meats, fish, cereals) ie beef jerky. Do not confuse with SALTING which is the DIFFUSION of water out of the cell.

Question 40

This form of preservation creates hypertonic environment (when water is diffused out of the cell) causes water loss from microbes then it will die.

Answer 40

Salting

Question 41

Does low temperatures (ie kept in refrigerator) also preserve food?

Answer 41

Yes - lower microbial metabolic and growth rates, retarding spoilage

Question 42

When did medicinal chemicals come into widespread use? By who?

Answer 42

In the 1800s & Lister

Question 43

What is the definition of "disinfectant"?

Answer 43

chemical used to kill or inhibit pathogenic microorganism on a lifeless object such as a tabletop.

Question 44

Disinfectants are used on ____, while antiseptics are used on ____.

Answer 44

Surfaces/Objects | Skin

Question 45

Microbicidals do what?

Answer 45

Inactive enzymes of organisms; interferes with metabolism. Kill!!!

Question 46

De-germing means what?

Answer 46

removing organisms from an object's surface.

Question 47

Hand-soap has a pH of what?

Answer 47

12

Question 48

To be a useful as a disinfectant or antiseptic it should:

Answer 48

``` • Kill or slow growth of microbes and be non-toxic to animals or humans • Be soluble in water or alcohol, and easy to apply • Have a relatively long shelf life • Be used in a diluted form • Act in a short time • Be non-staining and non-corrosive (doesn’t burn skin) • Be odorless, easy to obtain • Be relatively inexpensive ```

Question 49

What are things to consider with chemical agents at disinfectants or antiseptics?

Answer 49

1. Microbial susceptibility - leave the solution to kill on long enough. 2. Temperature and pH – consider temp of are cleaning, temp/ph can change reaction to disinfectant. 3. Concentration- higher conc more effective. 4. Environment – bioburden, more organisms present longer it takes to clean. 5. Endospore formers

Question 50

Thermal death time is what?

Answer 50

The time needed to kill the species.

Question 51

What is the thermal death point of E. Coli

Answer 51

55 mins to 2 hours (320F / 160C)

Question 52

When using a chemical should you concern yourself with how long to leave the solution on the surface?

Answer 52

Yes. Microbial susceptibility is different for each organism. You must take this into consideration.

Question 53

Does the temperature of a room effect the growth or organisms?

Answer 53

Yes.

Question 54

Can you kill endospores by boiling them?

Answer 54

The only sure way to rid of spores is to use an autoclave or incineration.

Question 55

What is the phenol coefficient?

Answer 55

Indicates disinfecting ability. Everything is compared to phenol which is given a 1.

Question 56

Is a phenol coefficient of 2 or 200 better? How about .04? Which one is most effective?

Answer 56

.04 is worse than phenol. 200 is better than 2.

Question 57

What do we look for when using the disk diffusion method for testing effectiveness of a chemical?

Answer 57

zone of inhibition

Question 58

True or False: Chlorine is used in municipal water supplies?

Answer 58

True!

Question 59

True or False? Iodine is used to clean wounds.

Answer 59

True

Question 60

What is the purpose of iodopors?

Answer 60

release idodine over a long period of time.

Question 61

Chemical agents that contain _________ __________, cross link proteins together so they can no longer function.

Answer 61

Heavy Metals

Question 62

Chemicals containing __________ denature proteins and disrupt the membrane (dissolve lipids)

Answer 62

Alcohol

Question 63

Which is more effective: 70% alcohol hand sanitizer or 90%? Why?

Answer 63

70% because it evaporates slower than 90%

Question 64

mechanically remove organisms from a surface

Answer 64

degerm

Question 65

_________ emulsify and solubilize particles clinging to a surface.. An example is soap.

Answer 65

Surfactants

Question 66

A strong surfactant that alters the membrane and cause cell lysis

Answer 66

detergent

Question 67

How does soap removes organisms from your hands?

Answer 67

Soap has a positive charge. Bacteria has a negative charge. Soap surrounds bacteria!