Micro Ch 23

1. Name the physical methods of controlling microbes:

1. Scrubbing 2. Incineration 3. Cremation 4.Dry Heat 5.Moist Heat 6. Cold 7. Light (UV)

The two aspects of the embalming process are:

1. disinfection 2. preservation

5 factors influence effectiveness of chemical agents

1. nature of the disinfectant 2. concentration of the disinfectant 3. nature of the material to be disinfected 4. number of microorganism present 5. length of exposure to disinfectant

3 levels in controlling microbial growth

1. sterilization 2. disinfection 3. antisepsis

Moist Heat

3 methods: Boiling, Free flowing steam, steam under pressure (19 psi at 121 deg. C for 15 miuntes)

Hexachlorophene

450x more effective than phenol

Quats

Quaternary ammonium compounds: damage cell membranes and denatures proteins, are surfactants

Aldehydes

React with proteins and alter their chemical structure. 1. Formalin - liquid form of formaldehyde 2. Glutaraldehyde - effective disinfectant and cold chemical sterilant. Inactivates DNA and RNA molecules

Iodine

a. oxidizes certain molecules within microbial cell i. Can be used in form of tincture or iodophore

Surfactant

alters surface tension of cell membrane, causing cell contents to leak out killing the cell

retort

combustion chamber

Sterilization

completely removing or destroying all life-forms, endospores, or their products (highest level of control)

Iodophore

compound of iodine and surfactants

Phenol

control microbial growth by denaturing protein and disrupting cell membranes

Cresols

derived from toluene; 3 forms 1. Otho-cresol 2. Meta-cresol 3. Para-cresol

Disinfection

destruction of pathogenic agents by disinfecting inanimate objects (less growth control, does not inactivate endospores, numbers of microbes reduced to longer presenting a serious health hazard)

a. Quaternary ammonium compounds

i. Known as quats ii. Damage cell membranes and denatures proteins iii. Are surfactants - alter surface tension of cell membranes, causing cell contents to leak out, killing the cell iv. Can cause birth defects in pregnant women who may be exposed through inhalation, ingestion, or skin absorption.

sporicide

kill bacteria and mold spores

Fungicide

kill fungi and their spores

Larvicide

kill larvae

germicide

kill many microbes, BUT NOT endospores

Viricide

kill viruses

Intersecticide

kills insects

Thermal death point

lowest temperature at which all microbes are killed in 10 minutes

Antisepsis

microbial growth is inhibited on living tissue (sanitization reduces microbes to safe levels)

ending -static

prevent growth of a particular microbe

Tincture

solution of iodine and alcohol

Decimal reduction time

time required to destroy 90% of microbes in a sample

ending -ide

will kill a particular microbe

Alcohols

a. - Ethyl alcohol and isopropyl alcohol i. Denature proteins and dissolve lipids in cell membrane ii. Most effective in aqueous solutions iii. Often added to other disinfectants, are volatile and cannot be used to steralize

Chlorine

a. - used to treat municipal drinking water and swimming pools i. Chlorine is a gas. Combined with water to form sodium hypochlorite ii. Is irritating to skin and mucous membranes iii. May react with certain organic compounds and are corrosive

Cremation

a. A form of incineration b. Combustion chamber is called retort c. Temperature is 1600 def F (871 deg C) d. Remains undergo complete combustion e. Remains devoid of soft tissue Are completely sterilized

Cold

a. Both refrigeration and freezing b. Does not destroy all vegetative cells or endospores c. Inhibits growth d. Bacteria multiply again when introduced to warm temperatures

Dry Heat

a. Denatures (coagulates) proteins b. Preferred over chemical methods i. Chemical methods may leave behind a toxic residue c. Requires more exposure time d. 200 deg C (392 deg F) for 1.5 hours

Light

a. Ultraviolet (UV) light b. UV is nonionizing radiation c. Damages cell's DNA d. Microbe has to be directly exposed to the UV light e. Many microbes contain pigments resistant to UV light

Incineration

a. Used most frequently to treat hazardous waste b. Removed by hazardous waste handler c. Then incinerated d. Waste must remain in combustion chamber sufficient time and temperature to mix with oxygen and combust completely e. Incineration is a form of sterilization 2. Cremation

Halogens

a. oxidize components of microbial cells Some react with proteins, chlorine and iodine used extensively

In controlling microbes, heat ____________________________ while cold _______________________.

denatures proteins in microbes ---- inhibits growth

Scrubbing

manual process by which microorganisms are removed from surface (should be vigorous and forceful) Only on inanimate objects- never human remains. - promotes accelerated decomp, can lead to leakage of body fluids

Thermal Death time

minimum time it takes to kill all microbes present

What kind of light controls microbial growth

UV