Control of Microorganisms Control of Microbial Growth Effected in two basic ways: 1.By Killing...
-
Upload
jody-mathews -
Category
Documents
-
view
222 -
download
0
Transcript of Control of Microorganisms Control of Microbial Growth Effected in two basic ways: 1.By Killing...
![Page 1: Control of Microorganisms Control of Microbial Growth Effected in two basic ways: 1.By Killing Microorganisms 2.By inhibiting the Growth of Microorganisms.](https://reader035.fdocuments.us/reader035/viewer/2022062309/56649eb45503460f94bbc490/html5/thumbnails/1.jpg)
Control of MicroorganismsControl of Microorganisms
![Page 2: Control of Microorganisms Control of Microbial Growth Effected in two basic ways: 1.By Killing Microorganisms 2.By inhibiting the Growth of Microorganisms.](https://reader035.fdocuments.us/reader035/viewer/2022062309/56649eb45503460f94bbc490/html5/thumbnails/2.jpg)
Control of Microbial GrowthControl of Microbial Growth
Effected in two basic ways:
1. By Killing Microorganisms
2. By inhibiting the Growth of Microorganisms
Usually involves the use of:
1. Physical Agents
2. Chemical Agents
![Page 3: Control of Microorganisms Control of Microbial Growth Effected in two basic ways: 1.By Killing Microorganisms 2.By inhibiting the Growth of Microorganisms.](https://reader035.fdocuments.us/reader035/viewer/2022062309/56649eb45503460f94bbc490/html5/thumbnails/3.jpg)
Principles of Microbial Control Principles of Microbial Control (Definitions)(Definitions)
• Prevention / Control of Growth to Prevent Infection and Spoilage
![Page 4: Control of Microorganisms Control of Microbial Growth Effected in two basic ways: 1.By Killing Microorganisms 2.By inhibiting the Growth of Microorganisms.](https://reader035.fdocuments.us/reader035/viewer/2022062309/56649eb45503460f94bbc490/html5/thumbnails/4.jpg)
Principles of Microbial Control Principles of Microbial Control (Definitions)(Definitions)
• Sterilization / Complete Destruction
- No degrees of sterilization (All or Nothing)
-
![Page 5: Control of Microorganisms Control of Microbial Growth Effected in two basic ways: 1.By Killing Microorganisms 2.By inhibiting the Growth of Microorganisms.](https://reader035.fdocuments.us/reader035/viewer/2022062309/56649eb45503460f94bbc490/html5/thumbnails/5.jpg)
Principles of Microbial ControlPrinciples of Microbial Control
• Disinfection / Reducing Growth Nonliving Surfaces
![Page 6: Control of Microorganisms Control of Microbial Growth Effected in two basic ways: 1.By Killing Microorganisms 2.By inhibiting the Growth of Microorganisms.](https://reader035.fdocuments.us/reader035/viewer/2022062309/56649eb45503460f94bbc490/html5/thumbnails/6.jpg)
Principles of Microbial ControlPrinciples of Microbial Control• Antisepsis / Reducing Growth on Living
Tissue
![Page 7: Control of Microorganisms Control of Microbial Growth Effected in two basic ways: 1.By Killing Microorganisms 2.By inhibiting the Growth of Microorganisms.](https://reader035.fdocuments.us/reader035/viewer/2022062309/56649eb45503460f94bbc490/html5/thumbnails/7.jpg)
Principles of Microbial ControlPrinciples of Microbial Control
• Antisepsis / Reducing Growth on Living Tissue
• Antiseptics are generally less toxic than disinfectants because they must not cause too much damage to the host living tissue. Examples of antiseptics include iodine, 70% ethanol and 3% hydrogen peroxide.
![Page 8: Control of Microorganisms Control of Microbial Growth Effected in two basic ways: 1.By Killing Microorganisms 2.By inhibiting the Growth of Microorganisms.](https://reader035.fdocuments.us/reader035/viewer/2022062309/56649eb45503460f94bbc490/html5/thumbnails/8.jpg)
Principles of Principles of Microbial Microbial ControlControl
• Sanitize
Subject to High Temperature Washing (Dishwashers)
![Page 9: Control of Microorganisms Control of Microbial Growth Effected in two basic ways: 1.By Killing Microorganisms 2.By inhibiting the Growth of Microorganisms.](https://reader035.fdocuments.us/reader035/viewer/2022062309/56649eb45503460f94bbc490/html5/thumbnails/9.jpg)
Principles of Microbial ControlPrinciples of Microbial Control
• Cide – Suffix Meaning to Kill
• Stat – Suffix Meaning to Inhibit
• Sepsis – Bacterial Contamination
• Asepsis – Lack of Bacterial Contamination
![Page 10: Control of Microorganisms Control of Microbial Growth Effected in two basic ways: 1.By Killing Microorganisms 2.By inhibiting the Growth of Microorganisms.](https://reader035.fdocuments.us/reader035/viewer/2022062309/56649eb45503460f94bbc490/html5/thumbnails/10.jpg)
Time to Kill in Proportion to the Time to Kill in Proportion to the Population SizePopulation Size
• Large Numbers Require Greater Time• Small Numbers Require Less Time
![Page 11: Control of Microorganisms Control of Microbial Growth Effected in two basic ways: 1.By Killing Microorganisms 2.By inhibiting the Growth of Microorganisms.](https://reader035.fdocuments.us/reader035/viewer/2022062309/56649eb45503460f94bbc490/html5/thumbnails/11.jpg)
Susceptibilities VarySusceptibilities Vary
• Endospores are Difficult to Kill• Organic Matter May Interfere with Heat
Treatments and Chemical Control Agents
![Page 12: Control of Microorganisms Control of Microbial Growth Effected in two basic ways: 1.By Killing Microorganisms 2.By inhibiting the Growth of Microorganisms.](https://reader035.fdocuments.us/reader035/viewer/2022062309/56649eb45503460f94bbc490/html5/thumbnails/12.jpg)
Control Agents Act ByControl Agents Act By
• Alteration of Membrane Permeability
- Susceptibility of membrane is due to its lipid and protein composition
- Control Agents can alter permeability• Damage to Proteins and Nucleic Acids
- Break hydrogen and covalent bonds in proteins
- Interfere with DNA, RNA, Protein
Synthesis
![Page 13: Control of Microorganisms Control of Microbial Growth Effected in two basic ways: 1.By Killing Microorganisms 2.By inhibiting the Growth of Microorganisms.](https://reader035.fdocuments.us/reader035/viewer/2022062309/56649eb45503460f94bbc490/html5/thumbnails/13.jpg)
Types of methods
• Physical
• Chemical
![Page 14: Control of Microorganisms Control of Microbial Growth Effected in two basic ways: 1.By Killing Microorganisms 2.By inhibiting the Growth of Microorganisms.](https://reader035.fdocuments.us/reader035/viewer/2022062309/56649eb45503460f94bbc490/html5/thumbnails/14.jpg)
Physical Methods of Microbial Physical Methods of Microbial ControlControl
![Page 15: Control of Microorganisms Control of Microbial Growth Effected in two basic ways: 1.By Killing Microorganisms 2.By inhibiting the Growth of Microorganisms.](https://reader035.fdocuments.us/reader035/viewer/2022062309/56649eb45503460f94bbc490/html5/thumbnails/15.jpg)
Physical Physical MethodsMethods
• Heat
• Filtration
• Low Temperatures
• Desiccation
• Osmotic Pressure
• Radiation
![Page 16: Control of Microorganisms Control of Microbial Growth Effected in two basic ways: 1.By Killing Microorganisms 2.By inhibiting the Growth of Microorganisms.](https://reader035.fdocuments.us/reader035/viewer/2022062309/56649eb45503460f94bbc490/html5/thumbnails/16.jpg)
HeatHeat
• Most Frequent and Widely Used.
• 1. Type of Heat– Moist
– Dry
2. Time of Application
3. Temperature
![Page 17: Control of Microorganisms Control of Microbial Growth Effected in two basic ways: 1.By Killing Microorganisms 2.By inhibiting the Growth of Microorganisms.](https://reader035.fdocuments.us/reader035/viewer/2022062309/56649eb45503460f94bbc490/html5/thumbnails/17.jpg)
• Thermal Death Point (TDP) / Lowest Temp to Kill All the Bacteria in a Broth in 10 Minutes
• Thermal Death Time (TDT) / Time Span Required to Kill All the Bacteria in a Broth at a Given Temperature
• Decimal Reduction Time (DRT) / Length of Time in Which 90% of a Bacterial Population will be Killed at a given Temperature
• Boiling / Kills Many Vegetative Cells and Inactivates Viruses Within 10 Minutes
![Page 18: Control of Microorganisms Control of Microbial Growth Effected in two basic ways: 1.By Killing Microorganisms 2.By inhibiting the Growth of Microorganisms.](https://reader035.fdocuments.us/reader035/viewer/2022062309/56649eb45503460f94bbc490/html5/thumbnails/18.jpg)
Moist Heat SterilizationMoist Heat Sterilization• Boiling• Autoclaving
![Page 19: Control of Microorganisms Control of Microbial Growth Effected in two basic ways: 1.By Killing Microorganisms 2.By inhibiting the Growth of Microorganisms.](https://reader035.fdocuments.us/reader035/viewer/2022062309/56649eb45503460f94bbc490/html5/thumbnails/19.jpg)
BoilingBoiling
• 100° C for 30 Minutes
• Kills Everything Except Some Endospores
![Page 20: Control of Microorganisms Control of Microbial Growth Effected in two basic ways: 1.By Killing Microorganisms 2.By inhibiting the Growth of Microorganisms.](https://reader035.fdocuments.us/reader035/viewer/2022062309/56649eb45503460f94bbc490/html5/thumbnails/20.jpg)
AutoclavingAutoclaving• Steam Under
Pressure• 121° C for 15
Minutes at 15 lb/in2
• Heat-labile Substances will be Denatured
• Steam Must Contact the Material
![Page 21: Control of Microorganisms Control of Microbial Growth Effected in two basic ways: 1.By Killing Microorganisms 2.By inhibiting the Growth of Microorganisms.](https://reader035.fdocuments.us/reader035/viewer/2022062309/56649eb45503460f94bbc490/html5/thumbnails/21.jpg)
Dry Heat SterilizationDry Heat Sterilization• Direct Flaming• Incineration• Hot-Air Sterilization (Oven)
Flaming the Loop
Flaming the loop helps to prevent contamination of the bacteria.
When flaming the loop, make sure that all of the wire has been heated to redness.
![Page 22: Control of Microorganisms Control of Microbial Growth Effected in two basic ways: 1.By Killing Microorganisms 2.By inhibiting the Growth of Microorganisms.](https://reader035.fdocuments.us/reader035/viewer/2022062309/56649eb45503460f94bbc490/html5/thumbnails/22.jpg)
IncinerationIncineration
• Burns and Physically Destroys Organisms
• Used for
a. Needles
b. Inoculating Wires
![Page 23: Control of Microorganisms Control of Microbial Growth Effected in two basic ways: 1.By Killing Microorganisms 2.By inhibiting the Growth of Microorganisms.](https://reader035.fdocuments.us/reader035/viewer/2022062309/56649eb45503460f94bbc490/html5/thumbnails/23.jpg)
Dry Heat (Hot Air Oven)Dry Heat (Hot Air Oven)
• 160° C for 2 Hours or 170° C for 1 hour
• Used for
a. Glassware
b. Metal
c. Objects That Won’t Melt
![Page 24: Control of Microorganisms Control of Microbial Growth Effected in two basic ways: 1.By Killing Microorganisms 2.By inhibiting the Growth of Microorganisms.](https://reader035.fdocuments.us/reader035/viewer/2022062309/56649eb45503460f94bbc490/html5/thumbnails/24.jpg)
PasteurizationPasteurization• A High Temperature
Is Used For a Short Time
• Batch Method– 63°C for 30 Minutes
– 71 for 15 seconds
• (UHT) sterilization 140°C for 3 seconds. – 2 months with only
minimal changes in flavor.
![Page 25: Control of Microorganisms Control of Microbial Growth Effected in two basic ways: 1.By Killing Microorganisms 2.By inhibiting the Growth of Microorganisms.](https://reader035.fdocuments.us/reader035/viewer/2022062309/56649eb45503460f94bbc490/html5/thumbnails/25.jpg)
FiltrationFiltration• The passage of a liquid or gas through a filter with
pores small enough to retain microbes.• Especially important to sterilize solutions which
would be denatured by heat (antibiotics, injectable drugs, amino acids, vitamins.)
![Page 26: Control of Microorganisms Control of Microbial Growth Effected in two basic ways: 1.By Killing Microorganisms 2.By inhibiting the Growth of Microorganisms.](https://reader035.fdocuments.us/reader035/viewer/2022062309/56649eb45503460f94bbc490/html5/thumbnails/26.jpg)
HEPA FiltersHEPA Filters• HEPA filters are High-Efficiency Particulate Air
filters designed for the filtration of small particles. Certified HEPA filters must capture a minimum of 99.97% of 0.3 microns contaminants.
![Page 27: Control of Microorganisms Control of Microbial Growth Effected in two basic ways: 1.By Killing Microorganisms 2.By inhibiting the Growth of Microorganisms.](https://reader035.fdocuments.us/reader035/viewer/2022062309/56649eb45503460f94bbc490/html5/thumbnails/27.jpg)
Low TemperaturesLow Temperatures
• Decreasing Temperature
Decreases Chemical Activity
• Low Temps are Not Bactericidal
![Page 28: Control of Microorganisms Control of Microbial Growth Effected in two basic ways: 1.By Killing Microorganisms 2.By inhibiting the Growth of Microorganisms.](https://reader035.fdocuments.us/reader035/viewer/2022062309/56649eb45503460f94bbc490/html5/thumbnails/28.jpg)
DesiccationDesiccation
• Disrupts Microbial Metabolism• Stops Growth / Microbes Are Still Viable• Freeze-drying / Dehydration
• Viruses and Endospores Can Resist Desiccation
![Page 29: Control of Microorganisms Control of Microbial Growth Effected in two basic ways: 1.By Killing Microorganisms 2.By inhibiting the Growth of Microorganisms.](https://reader035.fdocuments.us/reader035/viewer/2022062309/56649eb45503460f94bbc490/html5/thumbnails/29.jpg)
![Page 30: Control of Microorganisms Control of Microbial Growth Effected in two basic ways: 1.By Killing Microorganisms 2.By inhibiting the Growth of Microorganisms.](https://reader035.fdocuments.us/reader035/viewer/2022062309/56649eb45503460f94bbc490/html5/thumbnails/30.jpg)
Osmotic PressureOsmotic Pressure
• Plasmolysis
• Sugar Curing / Salting
• May Still Get Some Mold or Yeast Growth
![Page 31: Control of Microorganisms Control of Microbial Growth Effected in two basic ways: 1.By Killing Microorganisms 2.By inhibiting the Growth of Microorganisms.](https://reader035.fdocuments.us/reader035/viewer/2022062309/56649eb45503460f94bbc490/html5/thumbnails/31.jpg)
RadiationRadiation
• Ionizing Radiation
1. High Degree of
Penetration
2. Examples
- Gamma Rays
- X-rays
- High Energy
Electron Beams
• NonIonizing Radiation
1. Low Degree of Penetration
2. Harmful / Skin / Eyes
3. Cell Damage / Thymine
4. Germicidal / 260 nm
5. Example: Ultraviolet
![Page 32: Control of Microorganisms Control of Microbial Growth Effected in two basic ways: 1.By Killing Microorganisms 2.By inhibiting the Growth of Microorganisms.](https://reader035.fdocuments.us/reader035/viewer/2022062309/56649eb45503460f94bbc490/html5/thumbnails/32.jpg)
Ionizing RadiationIonizing Radiation• Ionizing radiation (gamma radiation) can
penetrate deeper into objects, and is used to sterilize food, drugs, and medical supplies
![Page 33: Control of Microorganisms Control of Microbial Growth Effected in two basic ways: 1.By Killing Microorganisms 2.By inhibiting the Growth of Microorganisms.](https://reader035.fdocuments.us/reader035/viewer/2022062309/56649eb45503460f94bbc490/html5/thumbnails/33.jpg)
Chemical Control MethodsChemical Control Methods
• Phenols and Phenolics• Halogens• Alcohols• Heavy Metals and Their Compounds• Surface-Active Agents• Quaternary Ammonium Compounds• Chemical Food Preservatives• Aldehydes
![Page 34: Control of Microorganisms Control of Microbial Growth Effected in two basic ways: 1.By Killing Microorganisms 2.By inhibiting the Growth of Microorganisms.](https://reader035.fdocuments.us/reader035/viewer/2022062309/56649eb45503460f94bbc490/html5/thumbnails/34.jpg)
![Page 35: Control of Microorganisms Control of Microbial Growth Effected in two basic ways: 1.By Killing Microorganisms 2.By inhibiting the Growth of Microorganisms.](https://reader035.fdocuments.us/reader035/viewer/2022062309/56649eb45503460f94bbc490/html5/thumbnails/35.jpg)
![Page 36: Control of Microorganisms Control of Microbial Growth Effected in two basic ways: 1.By Killing Microorganisms 2.By inhibiting the Growth of Microorganisms.](https://reader035.fdocuments.us/reader035/viewer/2022062309/56649eb45503460f94bbc490/html5/thumbnails/36.jpg)
Types of DisinfectantsTypes of Disinfectants
• Phenol and Phenolics
- Exert Influence By
1. Injuring Plasma membranes (lipids)
2. Inactivating Enzymes
3. Denaturing Proteins
Not effective against spores
![Page 37: Control of Microorganisms Control of Microbial Growth Effected in two basic ways: 1.By Killing Microorganisms 2.By inhibiting the Growth of Microorganisms.](https://reader035.fdocuments.us/reader035/viewer/2022062309/56649eb45503460f94bbc490/html5/thumbnails/37.jpg)
Types of Types of DisinfectantsDisinfectants
• Halogens- Can be Used Alone or in Solution- Chlorine -- Purifies Drinking Water
a. Forms an Acid Which is Bactericidalb. Disinfectant in Gaseous Form or in Solution as Calcium Hypochlorite
![Page 38: Control of Microorganisms Control of Microbial Growth Effected in two basic ways: 1.By Killing Microorganisms 2.By inhibiting the Growth of Microorganisms.](https://reader035.fdocuments.us/reader035/viewer/2022062309/56649eb45503460f94bbc490/html5/thumbnails/38.jpg)
Types of DisinfectantsTypes of Disinfectants
• Halogens- Iodine – combines with Amino Acids
a. Inactivates Enzymesb. Tincture / Alcohol
![Page 39: Control of Microorganisms Control of Microbial Growth Effected in two basic ways: 1.By Killing Microorganisms 2.By inhibiting the Growth of Microorganisms.](https://reader035.fdocuments.us/reader035/viewer/2022062309/56649eb45503460f94bbc490/html5/thumbnails/39.jpg)
Types of Types of DisinfectantsDisinfectants
• Alcohols
- Denature Proteins
- Dissolve Lipids
- Tinctures
- Wet Disinfectants
a. Aqueous Ethanol (60% - 95%)
b. Isopropal Alcohol
![Page 40: Control of Microorganisms Control of Microbial Growth Effected in two basic ways: 1.By Killing Microorganisms 2.By inhibiting the Growth of Microorganisms.](https://reader035.fdocuments.us/reader035/viewer/2022062309/56649eb45503460f94bbc490/html5/thumbnails/40.jpg)
Types of DisinfectantsTypes of Disinfectants
• Heavy Metals and Their Compounds
- Used for Burn Treatment
- Prevents Neonatal Gonorrheal Opthalmia
- Denature Proteins
- Example / Silvadene Ointment / Silver
![Page 41: Control of Microorganisms Control of Microbial Growth Effected in two basic ways: 1.By Killing Microorganisms 2.By inhibiting the Growth of Microorganisms.](https://reader035.fdocuments.us/reader035/viewer/2022062309/56649eb45503460f94bbc490/html5/thumbnails/41.jpg)
Types of DisinfectantsTypes of Disinfectants
• Surface-Active Agents
- Decrease Molecular Surface Tension
- Include Soaps and Detergents
- Soaps Have Limited Germicidal Action but
Assist in the Removal of Organisms by Scrubbing
- Acid-Anionic Detergents / Dairy
![Page 42: Control of Microorganisms Control of Microbial Growth Effected in two basic ways: 1.By Killing Microorganisms 2.By inhibiting the Growth of Microorganisms.](https://reader035.fdocuments.us/reader035/viewer/2022062309/56649eb45503460f94bbc490/html5/thumbnails/42.jpg)
Types of Types of DisinfectantsDisinfectants
• Quaternary Ammonium Compounds (QUATS)
- Cationic Detergents Attached to NH4
+1
- Disrupt Plasma Membranes
- Most Effective on Gram-Positive Bacteria
- Mouthwashes and Sore Throat Remedies
![Page 43: Control of Microorganisms Control of Microbial Growth Effected in two basic ways: 1.By Killing Microorganisms 2.By inhibiting the Growth of Microorganisms.](https://reader035.fdocuments.us/reader035/viewer/2022062309/56649eb45503460f94bbc490/html5/thumbnails/43.jpg)
Types of Types of DisinfectantsDisinfectants
• Chemical Food Preservatives
- Sorbic Acid
- Benzoic AcidInhibitFungus
- Propionic Acid
- Nitrate and Nitrite Salts / Meats /
To Prevent Germination of Clostridium botulinum endospores
![Page 44: Control of Microorganisms Control of Microbial Growth Effected in two basic ways: 1.By Killing Microorganisms 2.By inhibiting the Growth of Microorganisms.](https://reader035.fdocuments.us/reader035/viewer/2022062309/56649eb45503460f94bbc490/html5/thumbnails/44.jpg)
Types of Types of DisinfectantsDisinfectants
• Aldehydes
- Formaldehyde
- Glutaraldehyde
- Inactivate proteins by cross-linking with functional groups (–NH2, –OH, –COOH, —SH)
![Page 45: Control of Microorganisms Control of Microbial Growth Effected in two basic ways: 1.By Killing Microorganisms 2.By inhibiting the Growth of Microorganisms.](https://reader035.fdocuments.us/reader035/viewer/2022062309/56649eb45503460f94bbc490/html5/thumbnails/45.jpg)
Antibiotics• Cell wall antibiotics
• Bactracin
• Cycloserine
• Vancomycin
• Penicillin and beta lactam antibiotics Cell menbrane antibiotics
• DNA Synthesis Inhibitors
• RNA Synthesis Inhibitors
• Protein Synthesis Inhibitors
• Metabolism