Flashcards: micro 15

was in controlling microbiological growth

Exposure to boiling water for 10 minutes is sufficient to destroy vegetative cells and eukaryotic microorganisms but not high enough to kill bacterial endospores boiling does not sterilize

kills or destroys all viable microorganisms • Usingsteam under pressure in pressure cooker or autoclave) • Sterilization temperaturepressure-time: 121oC - 15 lbs/in2 - 15 minutes

-involves brief heating at 55-72oC

• Used for substances that are destroyed by high temperature like milk, juice, beer and wine to preserve them for long periods at the same time retaining foods’ flavor and value • Pasteurization temp. does not kill microbes but reduce their population so they can be stored longer

at 72oC for 15 se

- at 63 – 66 C for 30 min

A newer technique that produce milk that has a storage life of 3 months

temperature of 134oC for 1-2 secs

The materials are exposed to free flowing steamfor 30 – 40 min for 3 consecutive days • The temp. using this treatment does not get above 100oc

in a flame or heating coil direct exposure to such intense heat ignites and reduces microorganisms to ashes

Generally used to sterilize glasswares in the laboratory. • Involves the use of a laboratory oven •Sterilization time is 160-170oC for 2-3 hours • Not suitable for heat sensitive materials like plastic and rubber items

• Inhibit the growth and reproduction of microorganisms • Important in food microbiology and postharvest storage of fruits and vegetables to increase shelf-life • Most pathogenic microorganisms are mesophilic and do not grow at 4oC.

fluid is strained through a filter with openings large enough for the fluid to pass through but not the microorganisms • effective method of removing microorganisms from liquids • use membrane filters made up of cellulose acetate, cellulose nitrate, polycarbonate or polyvinylidine fluoride.

employ high efficiency particulate air (HEPA) filters • Prevents contamination of cultures in research labs • Used when culturing dangerous microbes like Mycobacterium tuberculosis and tumor viruses

Used to disinfect/sterilize the surface of the laminar flow hood, operating rooms to sterilize the air and any exposed surfaces

agents aimed at killing microorganisms

agents that temporarily prevent microorganisms from multiplying but not killing them

Agents used to destroy vegetative pathogens

from the term “asepsis” refers to any practice that prevents entry of infectious agents into sterile tissues thus preventing infection; • Agents applied directly to exposed body surfaces like skin, wounds, surgical incisions to destroy or inhibit vegetative pathogen.

a water-soluble cleansing agent which combines with impurities and dirt to make them more soluble, and differs from soap in not forming a scum with the salts in hard water.

agents that mechanically remove microorganisms (along with food debris) to reduce level of contaminant

(0.6 to 1 part of chlorine per million parts of water

-when combined with water, chlorine releases this acid which causes denaturing of enzymes thus suspending metabolic activities

rapidly penetrates cells of microorganisms and interfere with hydrogen and disulfide bonding of proteins thereby disturbing a variety of metabolic function in microbes

only ethyl and isopropyl suitable for microbial control; 50% or higher dissolve lipids, denature protein, disrupt cell surfac

mercury, silver and most other metals inactivate proteins bringing metabolism into a stand still

act as surfactants making them good wetting agents, cleansing agents and emulsifier

chemicals used in treatment, relief or prophylaxis of diseases

substances produced by microorganisms that can inhibit or kill other microorganisms

with characteristic β- lactam ring - inhibit cell wall synthesis - broad spectrum

B-lactam antibiotics

source of penicillin

source of cephalosporins

with 2 or more amino sugars and an aminocyclitol ring referred to as aminoglycoside - inhibit protein synthesis - broad spectru