Chapter 13 Control of Microbial growth

Question 1

What is fomites?

Answer 1

inanimate objects which may have microbes and aid in disease transmission

Question 2

what are the two factors that will influence the level of cleanliness for a fomite

Answer 2

1. the application in which it is to be used
2. the level of resistance that the potential bacteria have

Question 3

What is BSL?

Answer 3

biological safety level

Question 4

what risk is BSL-1?

Answer 4

Microbes that pose minimal risk

Question 5

What is needed for BSL-1?

Answer 5

-standard aseptic technique
-handwashing
-doors

Question 6

what are examples of microbes found in BSL-1?

Answer 6

-nonpathogenic strains of e.coli and bacillus subtilis
-viruses that don’t infect humans
-ex. baculovirus (insects)

Question 7

What risk is BSL-2?

Answer 7

moderate risk to workers and environment

Question 8

what precaution is used in BSL-2?

Answer 8

-restricted access
-required PPE
-biological safety cabinet
-self-closing doors
-eye washing
-autoclave

Question 9

what is a autoclave?

Answer 9

a specialized device for sterilizing materials with pressurized steam before use or disposal

Question 10

what are the bacteria in BSL-2?

Answer 10

-“indigenous”
-staphylococcus aureus
-salmonella spp.
-hepatitis, mumps, and measles viruses

Question 11

what risk is BSL-3?

Answer 11

microbes that cause serious or potentially lethal diseases through respiratory transmission

Question 12

what kind of microbes are in BSL-3?

Answer 12

-indigenous and exotic
- mycobacterium tuberculosis, bacillus anthracis, West Nile virus, HIV

Question 13

what precaution is needed in BSL-3?

Answer 13

-PPE
-respirator and work in biological safety cabinets
-hands free sink and eyewash station
-directional airflow

Question 14

what risk is BSL-4?

Answer 14

most dangerous and fatal

Question 15

what kind of microbes are in BSL-4?

Answer 15

dangerous and exotic, posing a high risk of aerosol-transmitted infections
-ex. ebola virus and marburg virus

Question 16

what precaution is needed in BSL-4?

Answer 16

-full body protection suit with pressure higher in the suit than outside
-HEPA-filtered exhaust
-not many labs in the US

Question 17

what is sterilization?

Answer 17

-the most extreme protocol for microbial growth
-the complete removal or killing of all vegetative cells, endospores, and viruses

Question 18

asepsis

Answer 18

maintain sterility

Question 19

what is sepsis?

Answer 19

a systemic inflammatory response to an infection that results in high fever, increased heart and respiratory rates, shock, and death

Question 20

what is commercial sterilization?

Answer 20

uses heat low enough to preserve the food content but high enough to kill microbes

Question 21

what is a common bacteria in canned food?

Answer 21

c.botulinum which is found in soil

Question 22

what is the goal of commercial sterilization?

Answer 22

1 endospore per can

Question 23

what is disinfection?

Answer 23

inactivates most microbes by using chemical or heating methods

Question 24

how is disinfection not sterilization?

Answer 24

endospores tend to survive even when all vegetative calls have been killed

Question 25

what are antiseptics?

Answer 25

chemically safe for use in living skin or tissues - ex. hydrogen peroxide and isopropyl alcohol

Question 26

what is degerming?

Answer 26

which microbial numbers are significantly reduced by gently scrubbing living tissue -ex. hand washing or alcohol in wipe

Question 27

what is sanitation?

Answer 27

cleaning of fomites enough deemed safe for the public - commercial dishwashing, regular surfaces

Question 28

what is the D-value?

Answer 28

the amount of time it takes for a specific protocol to produce a one-order of-magnitude decrease in the # of organisms or death of 90% of the population

Question 29

what does the microbial death curve show?

Answer 29

describes the progress and effectiveness of a particular protocol

Question 30

what are the factors that affect the effectiveness of the disinfectant?

Answer 30

the concentration and length of time

Question 31

what is a thermal death point?

Answer 31

the lowest temp. in which all microbes die in 10 minutes

Question 32

what is the difference between gravity displacement autoclaves and prevacume autoclaves?

Answer 32

Gravity displacemnt autoclaves- air sits at the bottom and it filters out prevacume: air is removed before the steam enters.

Question 33

what is pasteurization?

Answer 33

kills pathogens and reduces the amount of spoilage while maintaining food quality

Question 34

what does refrigeration do?

Answer 34

prevent microbial growth

Question 35

what is hyperbaric oxygen therapy do?

Answer 35

- increase oxygen - increases WBC - saturation in tissue helps with infections but there is a risk of oxygen toxicity.

Question 36

what does desiccation do?

Answer 36

- it is drying - controls microbial growth does not kill all microbes or its endospores

Question 37

lyophilization?

Answer 37

freeze drying - snap frozen then placed under vacuum -very effective in preventing microbial growth and preserving the integrity of food

Question 38

what does ionizing radiation include?

Answer 38

x-rays, gamma rays, high energy electron beams

Question 39

what does ionizing radiation do?

Answer 39

it passes into the cell alters the molecular structures and damages the cell ex. one way is putting breaks in the DNA

Question 40

what does nonionizing radiation include?

Answer 40

UV light

Question 41

how does UV light disinfect?

Answer 41

it causes thymine dimers to form between adjacent thymine, causing the DNA to not incorporate the right complementary (AA), creating a mutation and then death

Question 42

What are HEPA filters?

Answer 42

high-efficiency particulate air filter pore size 0.3um

Question 43

what are membrane filters?

Answer 43

filters for liquid functions pore size 0.2um

Question 44

what are BSC?

Answer 44

-Biological safety cabinets -filters the air coming in, filters the air coming out and or both