Microbial Control

Question 1

the process of destroying all forms of microbial life.

Answer 1

Sterilization

Question 2

An agent, usually a chemical that kills the grow forms but not necessarily the resistant spore forms of disease – producing microorganisms.

Answer 2

Disinfectant

Question 3

is the process of destroying infectious.

Answer 3

Disinfection

Question 4

A substance that opposes sepsis, to prevent the growth or action of microorganism or action microorganisms either by destroying or by inhibiting their growth and metabolism.

Answer 4

Antiseptics

Question 5

An agent that reduces the microbial population to safe levels as judged by public health requirements.

Answer 5

Sanitizer

Question 6

An agent that kills the growing forms but not necessarily the resistant spore forms of germs

Answer 6

Germicide (Microbicide)

Question 7

An agent that kills bacteria, similarly the terms fungicide, virucide and sporicidal refers to agents that kill fungi, viruses and spores respectively.

Answer 7

Bactericide

Question 8

A condition in which the growth of bacteria is prevented. Similarly, fungistatic describes an agent that stops the growth of fungi.

Answer 8

Bacteriostasis

Question 9

One that interferes with the growth and metabolism of microbes.

Answer 9

Antimicrobial agent

Question 10

Some antimicrobial agents are used to treat infections, and they called

Answer 10

chemotherapeutic agents

Question 11

Methods of Microbial Control:

Answer 11

1. Nature of the material to be treated
2. Types of microorganisms
3. Environmental conditions

Question 12

To cite an extreme example ( a chemical agent used in disinfectant contaminated utensils might be quite unsatisfactory for application to the skin; It might do serious injury to the tissue cells.

Answer 12

Nature of the material to be treated

Question 13

Chemical agents are not all equally effective against bacteria, fungi, viruses and other microorganisms.

Answer 13

Types of microorganisms

Question 14

The factors temperature, pH, time, concentrations and presence of extraneous organic material, may all have a bearing on the rate and efficiency of antimicrobial action.

Answer 14

Environmental conditions

Question 15

Temperatures below the minimum usually have a ____ action on microorganisms.

Answer 15

static

Question 16

An agent that is static in action will inhibit the growth of microorganisms.

Answer 16

static

Question 17

An agent that is cidal in action will kill microorganisms and viruses.

Answer 17

cidal

Question 18

Temperatures above the maximum usually have a ____ action on microorganisms.

Answer 18

cidal

Question 19

Keep in mind that when evaluating or choosing a method of controlling microorganisms, you
must consider the following factors which may influence antimicrobial activity:

Answer 19

1. the concentration and kind of a chemical agent used;
2. the intensity and nature of a physical agent used;
3. the length of exposure to the agent;
4. the temperature at which the agent is used;
5. the number of microorganisms present;
6. the organism itself; and
7. the nature of the material bearing the microorganism

Question 20

Vegetative microorganisms can generally be killed at temperatures from 50°C to 70°C with moist heat.

Answer 20

High Temperature

Question 21

are very resistant to heat and extended exposure to much higher temperature is necessary for their destruction

Answer 21

Bacterial endospores

Question 22

is generally more effective than dry heat for killing microorganisms because of its
ability to penetrate microbial cells.

Answer 22

Moist heat

Question 23

Moist heat kills microorganisms by

Answer 23

denaturing their
proteins

Question 24

employs steam under pressure.

Answer 24

Autoclaving

Question 24

Examples of dry heat include:

Answer 24

1. Hot air sterilization 2. Incineration

Question 24

will generally kill vegetative cells after about 10 minutes of exposure.

Answer 24

Boiling water

Question 25

kills microorganisms through a process of protein oxidation rather than protein coagulation.

Answer 25

Dry heat

Question 26

is the mild heating of milk and other materials to kill particular spoilage organisms or pathogens. It does not, however, kill all organisms.

Answer 26

Pasteurization

Question 27

inhibits microbial growth by slowing down microbial metabolism.

Answer 27

Low temperature

Question 28

generally has a static effect on microorganisms. Lack of water inhibits the action of microbial enzymes. Dehydrated and freeze-dried foods

Answer 28

Desiccation, or drying

Question 29

in their natural environments, are constantly faced with alterations in osmotic pressure. Water tends to flow through semipermeable membranes, such as the cytoplasmic membrane of microorganisms, towards the side with a higher concentration of dissolved materials (solute).

Answer 29

microorganisms

Question 30

the cell is said to be in a _______ environment and water will flow into the cell.

Answer 30

hypotonic

Question 31

CHARACTERISTICS OF GOOD ANTIMICROBIAL AGENT

Answer 31

1. Antimicrobial activity 2. Solubility 3. Stability 4. Nontoxicity to human and other animals 5. Homogeneity 6. Noncombination with extraneous organic material 7. Toxicity to microorganisms at room or body temperatures 8. Capacity to penetrate 9. Noncorroding and non - staining 10. Deodorizing ability 11. Detergent capacities 12. Availability

Question 32

The capacity of the substance to kill or inhibit microorganisms is the first requirement.

Answer 32

Antimicrobial activity

Question 33

The substance must be soluble in water or other solvents to the extent necessary for effective use.

Answer 33

Solubility

Question 34

Changes in the substance upon standing should be minimal and should not result in significant loss of germicidal action.

Answer 34

Stability

Question 35

Ideally, the compound should be lethal to microorganisms and non injurious to humans and other animals.

Answer 35

Nontoxicity to human and other animals

Question 36

The preparation must be inform in composition so that active ingredients are present in each application.

Answer 36

Homogeneity

Question 37

Many disinfectants have an affinity for proteins or other organic material

Answer 37

Noncombination with extraneous organic material

Question 38

In using the compound, it should not be necessary to raise the temperature beyond that normally found in the environment where it is to be use.

Answer 38

Toxicity to microorganisms at room or body temperatures

Question 39

Unless the substance can penetrate through the surfaces, its germicidal action is limited solely to the site of application.

Answer 39

Capacity to penetrate

Question 40

It should not rusts or otherwise disfigure metals nor stain or damage fabrics.

Answer 40

Noncorroding and non - staining

Question 41

Deodorizing while disinfecting is a desirable attribute. Ideally the disinfectant itself should either be odorless or have a pleasant smell.

Answer 41

Deodorizing ability

Question 42

A disinfectant which also a detergent (cleaning agent) accomplish two objectives and the cleansing action improves the effectiveness of the disinfectant.

Answer 42

Detergent capacities

Question 43

The compound must be available in large quantities at a reasonable price.

Answer 43

Availability

Question 44

Commonly used Chemical agents

Answer 44

1. Phenol and Phenolic compounds 2. Alcohols 3. Halogens (Iodine) 4. Heavy Metals and Their Compounds 5. Dyes 6. Synthetic Detergent 7. Quaternary Ammonium 8. Aldehydes 9. Formaldehyde

Question 45

is a unique and powerful sterilizing agent. It is use for sterilizing heat or moisture sensitive materials in hospitals, industry and laboratories has become universal.

Answer 45

Ethylene oxide

Question 46

Heavy metal

Answer 46

Mercury, Silver, Copper

Question 47

has the distinction of being used successfully in the 1880s by Joseph Lister, a surgeon, to reduce infection of surgical incisions and surgical wounds.

Answer 47

Phenol

Question 48

measures the disinfecting power or effectiveness of a disinfectant or antiseptic (the test disinfectant) compared to phenol: a well-established antiseptic agent.

Answer 48

the phenol – coefficient technique.

Question 49

are inactive and dormant structures.

Answer 49

Spores

Question 50

are actively growing cells that form the endospore.

Answer 50

Vegetative cells

Question 51

CH3CH2OH in concentrations between 50 and 90s, is effective against vegetative or non – spore forming cells.

Answer 51

ethyl alcohol

Question 52

is less bactericidal than ethyl alcohol; furthermore it is highly poisonous.

Answer 52

methyl alcohol

Question 53

is one of the oldest and most effective germicidal agents. It has been in use for more than a century, having been recognized by the US Pharmacopoeia in 1830.

Answer 53

halogens (iodine)

Question 54

are mixtures of iodine with surface – active agents which act as carriers and solubilizers for the iodine.

Answer 54

iodophores

Question 55

Two classes of dye compounds

Answer 55

triphenylmethane and acridine dyes.

Question 56

These compounds exhibit selective inhabitation against bacteria, particularly staphylococci and Gonococci.

Answer 56

Acridine Dyes

Question 57

Most compounds of the germicidal cationic – detergent class are

Answer 57

quaternary ammonium salts.

Question 58

is the simplest compound in the aldehyde series. It is a gas that is stable only in high concentrations and at elevated temperatures.

Answer 58

Formaldehyde

Question 59

is a unique and powerful sterilizing agent. It is use for sterilizing heat or moisture sensitive materials in hospitals, industry and laboratories has become universal.

Answer 59

Ethylene oxide