Control of Microbial Growth

Question 1

What is disinfection?

Answer 1

Destroying all harmful microorganisms
Destroys vegetative cells
NOT the same thing as sterility

Question 2

When you disinfect something, do you kill the endospores as well?

Answer 2

NO

Question 3

Disinfectant definition

Answer 3

A chemical used to treat an INERT surface

Question 4

What is degermination?

Answer 4

Mechanically removing microbes, not really killing them
Ex: Degerming a table top

Question 5

Sanitization is?

Answer 5

When you lower the microbe count just low enough to where it is safe to consume
Ex: high temp washing or chemical disenfectant

Question 6

Biocide…?

Answer 6

Kills microorganisms except endospores

Question 7

Bacteriostasis…?

Answer 7

Inhibits growth
Does NOT kill the microbes

Question 8

Sepsis is ?

Answer 8

Bacterial contamination

Question 9

Aseptic means?

Answer 9

Object/ area is free of pathogens

Question 10

Asepsis means?

Answer 10

Absensce of significant contamination

Question 11

The rate of microbial death is?

Answer 11

A constant rate

Question 12

Microbial death is graphed as a?

Answer 12

Log

Question 13

What are factors that influence antimicrobial effectiveness?

Answer 13

Number of microbes
Time of exposure
Environmental influences
Microbial characteristics

Question 14

What are the ways antimicrobial stuff damages microbes?

Answer 14

They can damage the lipids/ plasma mebrane
They can damage proteins
They can damage nucleic acids

Question 15

How can antimicrobials damage lipids?

Answer 15

Damage to the lipids causes leakage of the cell and its components
This stops binary fission

Question 16

How do antimicrobials damage proteins?

Answer 16

They shut down the enzymes
By damaging proteins, they break hydrogen bonds
Stop binary fission

Question 17

HOW do antimicrobials damage nucleic acids?

Answer 17

By heat
Radiation
Chemicals
Stops protein synthesis, binary fission

Question 18

What is the thermal death point? (TDP)

Answer 18

Lowest temp that cells in a liquid culture will DIE in 10 MINUTES
Unit is celsius

Question 19

What is thermal death time? (TDT)

Answer 19

Minimal time that all bacteria in a liquid culture are dead at a particular temperature
Unit is seconds or minutes

Question 20

What is the decimal reduction time? (DRT)

Answer 20

The minutes it takes to kill 90 percent of a specific population of bacteria at a given temperature

Question 21

What are the types of Moist Heat sterilization?

Answer 21

Boiling/ free flowing steam
Autoclaving
Pasteurization

Question 22

What happens in Boiling/ free flowing steam (moist heat sterilizaton)?

Answer 22

Kills vegetative forms of bacterial pathogens, viruses, and fungi within 10 minutes
Endospores can last up to 20 hours in this process

Question 23

What do all types of moist heat sterilization do?

Answer 23

Coagulate and denature proteins

Question 24

What happens in autoclaving?

Answer 24

Uses high temp and pressure to kill microorganisms as well as endospores
Preferred method of sterilization in hospitals

Question 25

What happens in Pasteurization?

Answer 25

It uses high heat for a short amount of time Reduces spoilage organisms and pathogens 72 degrees celsius for 15 seconds

Question 26

What happens when you dry heat?

Answer 26

It kills bacteria by using oxidative effects

Question 27

What's an example of dry heating?

Answer 27

Direct flaming Ex: Innoculating the tools

Question 28

Types of radiation techniques?

Answer 28

Ionizing Non- ionizing Microwaves

Question 29

Types of ionizing radiation examples?

Answer 29

X-rays Gamma rays Electron beams

Question 30

When using ionizing radiation, how does it work?

Answer 30

It destroys DNA by lethal mutations

Question 31

Types of non-ionizing radiation?

Answer 31

Ultraviolet

Question 32

When using non-ioning radiation, how does it work?

Answer 32

Creates thymine dimers which damage DNA

Question 33

What are the types of physical control of microbial growth?

Answer 33

Heat Radiation