1. Control of Microorganisms

2. Scientific Control Louis Pasteur Joseph Lister: 1) hand washing
2) aseptic surgery techniques
What are the implications for the embalmer?

3. Readings question #1:
What is the difference between sterilization, disinfection, and antisepsis?

4. Actions of Microbial Control Agents
2 basic ways:
1) alteration of membrane permeability
2) damage to proteins and nucleic acids

5. Physical Methods Scrubbing Heat: heat resistance varies among microbes
Dry heat: incineration, cremation, hot-air sterilization
Moist heat: kills by coagulation of proteins (denaturation)
boiling, free flowing steam (unpressurized), steam under pressure
Pasteurization: mild heating

6. Physical Methods (cont’d)
Cold: bacteriostatic effect
Radiation: ionizing radiation
-gamma rays, x-rays, electron beams
nonionizing radiation
-UV light
Microwaves: solid foods heat unevenly due to uneven distribution of moisture
Pork: trichinosis

7. Chemical Methods living tissue and inanimate objects
few achieve sterility
reduce microbial populations to safe levels or remove vegetative forms of pathogens from objects
no single disinfectant is appropriate for all circumstances

8. Germicides
Bactericides
Fungicides
Viricides
Insecticides
Larvicides
Sporicides

9. Factors Influencing Chemical Agents
Read the label!!!!
nature and concentration of disinfectant
nature of material to be disinfected
number and type of microorganisms present
length of exposure
temperature and pH during exposure

10. Halogens Readings question #2: What are halogens and how do they work?
Chlorine: hypochlorites (bleaches)
Iodine: iodophore e.g. polyvinylpyrrolidone

11. Alcohols Readings question #3:
How do alcohols control microbial growth?
Two of the most commonly used:
ethanol
isopropanol

12. Aldehydes Readings question #4:
What are aldehydes and how do they work?
2 examples:
formalin
glutaraldehyde

13. Phenolic Compounds Readings question #5:
Give two examples of phenolic compounds, and explain how each control microbial growth.
carbolic acid (phenol)
cresols
hexachlorophene

14. Quaternary Ammonium Compounds
Readings question #6:
What are “quats”? How do surfactants effect cells?
Zephiran, Cepacol
bactericidal: gram-positive bacteria
fungicidal, amoebicidal, virucidal (enveloped viruses)
do not kill endospores or mycobacteria
Pseudomonas grow in quats