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| Microbiology Sterilization Notes |
WHAT IS STERILIZATION |METHODS OF STERILIZATION |MERITS, DEMERITS AND APPLICATIONS OF DIFFERENT METHODS OF STERILIZATION | PHARMACEUTICAL IMPORTANCE OF STERILIZATION
STERILIZATION:-
Contents
WHAT IS STERILIZATION
METHODS OF STERILIZATION
MERITS, DEMERITS AND APPLICATIONS OF DIFFERENT METHODS OF STERILIZATION
PHARMACEUTICAL IMPORTANCE OF STERILIZATION
WHAT IS STERILIZATION:
Sterilization may be described as any process that efficiently kills or removes transmissible retailers (consisting of fungi, bacteria, viruses and prions) from a floor, device, ingredients, medicines, or organic way of life medium.
METHODS OF STERILIZATION
The numerous techniques of sterilization are:
1. Physical Method
Thermal (Heat) techniques
Radiation method
Filtration approach
2. Chemical Method
a. Gaseous method
PHYSICAL METHODS:
HEAT STERILIZATION:
Heat sterilization is the maximum extensively used and reliable approach of sterilization, regarding destruction of enzymes and other essential cell elements.
This approach of sterilization can be implemented simplest to the THERMO STABLE PRODUCTS and Moisture Sensitive MATERIALS.
Dry Heat (one hundred sixty-1800°C)
Sterilization for thermo stable products
Moist warmness (121-1340 °C)
sterilization is used for moisture- resistant substances.
The performance with which heat is able to inactivate microorganisms relies upon degree of warmth, the publicity time and the presence of water.
The motion of warmth might be due to induction of deadly chemical activities mediated thru the motion of water and oxygen.
In the presence of water plenty decrease temperature time exposures are required to kill microbe than in the absence of water.
Thermal strategies consists of:
Dry Heat Sterilization
Ex：l. Incineration
Red heat
Flaming
Hot air oven
Moist Heat Sterilization
1 .Dry saturated steam — Autoclaving
Boiling water/ steam at atmospheric
pressure
Hot water beneath boiling point
Dry Heat Sterilization
It employs better temperatures inside the range of one 60°C and requires exposures time up to hours, relying upon the temperature hired.
The gain of dry heat consists of precise penetrability and on-corrosive nature which makes it applicable for sterilizing glass wares and steel surgical units. It is likewise used for sterilizing nonaqueous thermo strong drinks and thermo solid powders.
Dry heat destroys bacterial endotoxins (or pyrogens) which are difficult to do away with by means of different method and this property makes it relevant for sterilizing glass bottles which can be to be stuffed aseptically
Physical methods for Sterilization
Sunlight:
The microbicidal activity of sunlight is specifically due to the presence of ultra violet rays in it.
It is answerable for spontaneous sterilization in natural conditions.
In tropical nations, the daylight is extra powerful in killing germs due to mixture of ultraviolet rays and heat.
By killing micro organism suspended in water, sunlight affords natural technique of disinfection of water bodies inclusive of tanks and lakes.
Heat:
Heat is taken into consideration to be most reliable technique of sterilization of articles that could resist warmness.
Heat acts through oxidative effects as well as denaturation and coagulation of proteins.
Those articles that can not resist high temperatures can nonetheless be sterilized at lower temperature by using prolonging the length of publicity.
Factors affecting sterilization by way of heat
Nature of heat: Moist warmth is greater effective than dry warmth
Temperature and time: temperature and time are inversely proportional. As temperature will increase the time taken decreases.
Number of microorganisms: More the range of microorganisms, higher the temperature or longer the period required.
Nature of microorganism: Depends on species and strain of microorganism, sensitivity to warmness may also vary. Spores are particularly resistant to heat.
Type of material: Articles which might be heavily infected require better temperature or prolonged publicity. Certain warmness touchy articles have to be sterilized at decrease temperature.
Presence of natural fabric: Organic substances which includes protein, sugars, oils and fats increase the time required.
Action of heat:
Dry heat acts by means of protein denaturation, oxidative damage and poisonous results of accelerated tiers of electrolytes.
The wet warmth acts by using coagulation and denaturation of proteins.
Moist warmth is superior to dry heat in action.
Temperature required to kill microbe by using dry heat is extra than the moist warmth.
Thermal dying time is the minimum time required to kill a suspension of organisms at a predetermined temperature in a designated surroundings.
DRY HEAT STERILIZATION
Articles along with bacteriological loops, immediately wires, pointers of forceps and searing spatulas are sterilized by means of conserving them in Bunsen flame till they emerge as purple warm.
This is a simple approach for effective sterilization of such articles, however is restrained to those articles that can be heated to redness in flame.
Flaming
This is a method of passing the object over a Bunsen flame, however no longer heating it to redness.
Articles together with scalpels, mouth of test tubes, flasks, glass slides and cover slips are handed through the flame some instances.
Even even though maximum vegetative cells are killed, there may be no guarantee that spores too might die on such short publicity.
This method too is constrained to those articles that may be uncovered to flame. Cracking of the glassware may also arise.
Incineration:
This is a way of destroying contaminated cloth through burning them in incinerator.
Articles which includes dirty dressings; animal carcasses, pathological cloth and bedding and so forth. Need to be subjected to incineration.
This approach effects inside the loss of the object, therefore is suitable simplest for those articles that ought to be disposed.
Burning of polystyrene materials emits dense smoke, and therefore they should not be incinerated.
Hot air oven
This technique was added with the aid of Louis Pasteur.
Articles to be sterilized are uncovered to excessive
temperature (160°C) for period of one hour in an electrically heated oven.
Since air is poor conductor of heat, even distribution of warmth all through the chamber is performed with the aid of a fan.
The warmness is transferred to the thing by radiation, conduction and convection.
The oven ought to be equipped with a thermostat manipulate, temperature indicator; meshed shelves and should have adequate insulation.
Hot air oven
Articles sterilized:
Metallic devices (like forceps, scalpels, scissors), glass wares (which includes petri-dishes, pipettes, flasks, all-glass syringes), swabs, oils, grease, petroleum jelly and a few pharmaceutical products.
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