Controlling Microbial Growth

Question 1

Antisepsis

Answer 1

Reduction in the number of microorganisms and viruses on living tissues.
-Safe to use on Skin
-Examples: Iodine, Alcohol

Question 2

Aseptic

Answer 2

Refers to an environment or procedure free of pathogenic contaminants
-Area free of pathogens
-Examples: Hand washing, preparations of surgical field.

Question 3

-cide/-cidal

Answer 3

indicating destruction of a type of microbe
-To kill or destroy microbes
-Example: Bactericide/ Fungicide

Question 4

Disinfection

Answer 4

Destruction of most microorganisms and viruses on nonliving tissues
-To kill non living tissues
-Example: Soap, alcohols

Question 5

Pasteurization:

Answer 5

Use of heat to destroy pathogens and reduce the number of spoilage microorganisms
-Example: Milk, Fruit Juice

Question 6

Sanitization

Answer 6

Removal of pathogens from objects to meet public health standards
-Example: Washing tableware in hot water

Question 7

Antimicrobials

Answer 7

Disinfecting agents that are naturally produced by microorganisms

Question 8

-static/-static

Answer 8

indicating inhibition, but not complete destruction of microbes
-Does not allow growth of something but does not kill it (Refrigerator)
-Example- Bacteriostatic, fungistatic

Question 9

Sterilization

Answer 9

Destruction of all microorganisms and virus in or an object
-Kill all microorganisms
-Example- preparation of microbiological culture media

Question 10

Actions Antimicrobial Agents
(Next topic)

Answer 10

-If you want to kill bacteria attack cell wall, No harm will be done to humans because we not have cell wall

Question 11

Alteration of cell wall and membranes

Answer 11

Cell wall maintains integrity of cell
-When damaged , cell burst

Question 12

Cytoplasmic membrane controls passage of chemicals into and out of cell.

Answer 12

When damaged cellular contains leak out due to osmotic pressure

Question 13

Damage to proteins and nucleic acids

Answer 13

Protein function depends on 3-D shape
-Extreme heat or certain chemicals denature proteins
-Damage to nucleic acid would also affect protein synthesis

Question 14

Chemicals, radiations and heat can alter/destroy nucleic acids

Answer 14

-produce fatal mutants
-Halt protein synthesis through action on RNA

Question 15

*Important
Ideally, Agents should be

Answer 15

-Inexpensive
-Fast-acting
-Stable during storage
-Capable of controlling microbial growth whole being harmless to humans, humans, animals and objects

Question 16

Heat related Methods
(Next topic) Boiling and Autoclaving

Answer 16

Next topic

Question 17

Most Heat (Boiling)

Answer 17

-Kills vegetative cells of bacteria and fungi, protozoa, most viruses
-Boiling time is critical (Different elevations require Different bowling times)
-Endospores, protozoans, cysts and some virus can survive

Question 18

Moist Heat (Autoclaving)

Answer 18

-Pressure applied to Boiling water prevents steam from escaping
-Boiling temperature increases as pressure increases
-Autoclave conditions- 121°C, 15 psi, 15 minutes

Question 19

Moist Heat (Pasteurization)

Answer 19

-Not sterilization (Heat tolerant Microbes survived)
-Used for milk, ice cream, yogurt and fruit

Question 20

Incineration

Answer 20

-Burns Items completely
(Can be used to discard public waste)
(An effective mean of sterilization)

Question 21

Refrigeration and Freezing

Answer 21

Decrease microbial metabolism, growth, and reproduction
-Chemical reaction occurs more slowly at low temperatures
-Liquid Water not available
Psychrophilic microbes can multiply in refrigerated foods
Refrigeration halts growth of most pathogens (DOES NOT KILL BACTERIA)
Slow freezing more effective than quick freezing (If you freeze bacteria you can kill most Bacteria)
Organisms vary in susceptibility to freezing

Question 22

Desiccation and Lyophilization

Answer 22

Desiccation=to dry (Test Question)
Lyophilization-remove water (test Question)
-Drying inhibits growth because of removal of water. (Dry heat is an effective means of sterilization)
-Lyophilization used for a long term of preservation. (Prevents formation of damaging ice crystals)

Question 23

Radiation

Answer 23

-Ionizing radiation –>Wavelengths shorter than 1nm, Ejects electrons from atoms to create ions, Ions disrupt hydrogen bonding (Can denture DNA)
-Gamma irradiation is used for fresh fruits and vegetables

Question 24

Alcohols

Answer 24

-Intermediate level of
-Denature proteins and disrupts cytoplasmic membranes
-More effective than soap in removing bacteria from hands
- Used for both antiseptics and disinfection (Swabbing of skin with 70% of ethanol