Micro control growth

Question 2

Sterilization

Answer 2

destruction of all microbes

Question 3

Aseptic

Answer 3

environment free of pathogens

Question 4

Disinfection

Answer 4

destroy most microorganisms and viruses on nonliving material

Question 5

Antiseptic

Answer 5

removal of pathogens from living tissue (not as damaging)

Question 6

Pasteurization

Answer 6

heat to remove pathogens and spoilage microorganisms; goal is to kill the pathogens that would grow at physiological temp

Question 7

Bacteriostatic

Answer 7

to inhibit the growth of bacteria, eg refrigeration

Question 8

Bacteriocidal

Answer 8

kill bacteria

Question 9

UV light bacteriostatic or bacteriocidal?

Answer 9

bacteriocidal (works best on replicating cells)

Question 10

Modes of action

Answer 10

Alteration of cell walls or cytoplasmic membranes, Interference with protein and nucleic acid structure

Question 11

Factors affecting efficacy of antimicrobial methods

Answer 11

Nature of site to be treated (living tissue, surgical instruments); Degree of susceptibility of microbes involved (study killing of major pathogens); Environmental conditions that pertain

Question 12

Evaluating disinfectants and antiseptics

Answer 12

Phenol Coefficient; Use-Dilution Test; Disk-Diffusion Method; In-Use Test

Question 13

Phenol Coefficient

Answer 13

evaluate compared to phenol

Question 14

Use-Dilution Test

Answer 14

different dilutions at different times

Question 15

Disk-Diffusion Method. Can we always be sure that a particular compound has no effect?

Answer 15

Plate bacteria, place a paper with disks on it, measure zone of inhibition. If it doesn’t diffuse it won’t produce a result (high molecular weight of material)

Question 16

In-Use Test

Answer 16

swab before and after use of chemical

Question 17

Physical methods. Think of how each works

Answer 17

Extremes of heat, Extremes of cold (inhibit), Desiccation, Filtration, Osmotic pressure, Radiation. Look at the table 9.4! Know the action!

Question 18

Thermal death point

Answer 18

lowest temperature that kills all cells (of one strain) in broth in 10 minutes

Question 19

D (decimal reduction time) value

Answer 19

exposure time at a given temperature needed to reduce the number of viable microorganisms by 90%, then 90% of 10%, then 90% of 1%, etc.

Question 20

Canning food

Answer 20

Uses D value to kill

Question 21

What’s the ultimate test to see if a sterilization technique works?

Answer 21

Use a bacteria that likes to grow at high temp (55C) and produces spores and see if it dies

Question 22

Filtration

Answer 22

used when purifying something that is heat sensitive (ie antibiotic wouldn’t tolerate heat); filters have holes of .1 µm

Question 23

Chemical methods

Answer 23

affect cell walls, membranes, proteins, and DNA, almost always denatures proteins; effects vary with time, temp, [ ], etc.