Chapter 5

Question 1

Joseph Lister

Answer 1

Introduced methods to prevent infection of wounds

Applied carbolic acid (phenol) to prevent infection to wounds

Question 2

Sterilization

Answer 2

Removal or destruction of all micro organisms and viruses

Question 3

Disinfection

Answer 3

Elimination of most or all pathogens

Question 4

Antiseptics

Answer 4

Chemicals used on living tissues

Question 5

Decontamination

Answer 5

Reduces number of pathogens to a safe level

Question 6

Sanitization

Answer 6

Substantially reduce his microbial population to meet excepted health standards that minimize spread of disease

Question 7

Preservation

Answer 7

Process of delaying spoilage of perishable products

Question 8

Pasteurization

Answer 8

Brief heating to reduce number of spoilage organisms, destroy pathogens without changing characteristics of product

Question 9

Biosafety levels (CDC)

Answer 9

BSL-1: microbes not known to cause disease

BSL-4: lethal pathogens for which no vaccine or treatment exists

Question 10

Antimicrobial of choice factors

Answer 10

Type and number of microbes

Environmental conditions

Risk of infection

Composition of item to be treated

Question 11

Bacterial endospores

Answer 11

Most resistant; only extreme heat or chemical treatment destroys them

Question 12

Protozoan cysts and oocysts

Answer 12

Resistant to disinfectants; excreted In feces; cause diarrheal disease if ingested; destroyed by boiling

Question 13

Mycobacterium

Answer 13

Waxy cell walls makes resistant to many chemical treatments

Question 14

Pseudomonas

Answer 14

Resistant to and can actually grow in some disinfectants

Question 15

Non enveloped viruses

Answer 15

Lack lipid envelope; more resistant to disinfectants

Question 16

Decimal reduction time

Answer 16

(D value) is time required to kill 90% of population under specific conditions

Question 17

Heat treatment

Answer 17

Can sterilize or disinfect

Moist heat: irreversibly denatures proteins

Boiling destroys microorganisms and viruses, endospores can survive

Question 18

Pasteurization

Answer 18

Destroys heat sensitive pathogens, spoilage organisms

High-temperature short time method: Milk 72°C for 15 secs; ice cream 82°C for 20 secs

Ultra high temperature method: shelf stable boxed juice and milk; Milk 140°C for a few secs

Question 19

Autoclave

Answer 19

Sterilizes using pressurized steam

121°C and 15lb per square inch in 15 mins

Prions: 132°C for 1 hour

Question 20

Dry heat

Answer 20

Less effective than moist heat

200°C for 90 mins

Used for glass, powders, oils, dry materials

Question 21

High efficiency particulate air (HEPA) filters

Answer 21

Remove nearly all microbes over 0.3 micrometer from air

Question 22

Ionizing radiation

Answer 22

Gamma rays and x-rays that directly destroy DNA and damages cytoplasmic membranes

Irradiation
Gamma Rays: sterilize heat sensitive materials, after packaging

UV rays: destroys DNA of microbes in air, water, she surfaces

Question 23

High pressure processing

Answer 23

Decreases the number of micro organisms in commercial food products like fruit juice and guacamole

Pressure up to 120,000 pounds per square inch

Question 24

Physical methods to destroy microorganisms and viruses

Answer 24

Filtration

Irradiation

High pressure

Moist heat

Dry heat

Question 25

Sterilants

Answer 25

Destroy all microbes; also called sporocides

Question 26

High level disinfectants

Answer 26

Destroys viruses, vegetative cells Do not reliably kill endospores

Question 27

Intermediate level disinfectants

Answer 27

Destroy vegetative bacteria, mycobacteria, fungi, and most viruses

Question 28

Low level disinfectants

Answer 28

Destroy fungi, vegetative bacteria except mycobacteria, and enveloped viruses Do not kill endospores

Question 29

Germicidal chemicals

Answer 29

Regulated by FDA or EPA Careful instructions regarding dilution, temperature, and duration of time needed for effectiveness

Question 30

Germicidal chemical factors

Answer 30

Toxicity Residue: can be toxic or corrosive Cost she availability Storage and stability Environmental risk Material being treated: no electronics

Question 31

Alcohols

Answer 31

60 to 80% ethyl or isopropyl alcohol, kills vegetative bacteria and fungi Not reliable against endospores, non-enveloped viruses Denatures essential proteins, damages membranes Tincture- antimicrobial chemical dissolved in alcohol

Question 32

Aldehydes

Answer 32

Glutaraldehyde: immersion 10 to 12 hours, Toxic formaldehyde: germicide that kills most microbes ortho-phthalaldehyde: less toxic, turns skin gray Inactivates proteins and nucleic acids

Question 33

Biguanides

Answer 33

Antiseptic that destroys vegetative bacteria, fungi, some envelope viruses Chlorhexidine Low toxicity

Question 34

Ethylene oxide

Answer 34

Gaseous stimulant for heat or moisture sensitive items Reacts with proteins to destroy microbes, including in the spores and viruses Limitation: explosive, toxic, carcinogenic

Question 35

Halogens

Answer 35

Reacts with proteins, cellular components Chlorine dioxide (bleach): used as disinfectant and sterilant Iodine: kills vegetative cells, unreliable on endospores

Question 36

Metal compounds

Answer 36

Combine with sulfhydryl groups (-SH) of proteins High concentrations can be too toxic Mercury, tin, copper, were once used as preservatives

Question 37

Ozone

Answer 37

And unstable form of oxygen that readily breaks down to a ineffective form, used to disinfect water and waste water

Question 38

Peroxygens

Answer 38

Readily biodegradable and less toxic than traditional alternatives Hydrogen peroxide Peracetic acid: stronger ^

Question 39

Phenolic compounds

Answer 39

Remains effective in presence of detergents and organic contaminants Leaves antimicrobial residue Triclosan Hexachlorophene: can cause neuro damage

Question 40

Quaternary ammonium compounds

Answer 40

Nontoxic, can be used on food prep surfaces Inactivates by soap Disinfects into animate objects

Question 41

Weak organic acids

Answer 41

Benzoic, sorbic, propionic Affect cell membrane Control molds and bacteria in foods

Question 42

Nitrate

Answer 42

Used in processed meats to inhibit endospore germination and vegetative cell growth Gives meat pink color May be carcinogenic once cooked

Question 43

Lyophilization

Answer 43

Freeze drying of foods Stabs microbial growth but does not reliably kill Coffee, meats, vegetables