Health & Safety
1. Personal hygiene
- Appropriately, fresh and clean dressed
- Always smell fresh
- Lightly use perfume
- Appropriately nails length and clean
- No jewellery
- Always wash your hands
- Any wand or cuts must be a cover by plaster
- Always clean your brushes after use
- Buy clear bags for any unclean brushes
- Lids always replace it
- Everything label it
3.Some tips for remaining professional
as a make-up artist
- Never show up with a dirty brushes
- Don’t double- dip from products containers
- Wash your hands
- Don’t wear a perfume ( some people might be an allergic)
Sterilization is the killing or removal of all
micro-organisms, including bacterial spores which are highly resistant.
Sterilization is an absolute term, i.e... the article must be sterile meaning the
absence of all micro-organisms.
Disinfection is the killing of many, but not all
microorganisms. It is a process of reduction of number of contaminating
organisms to a level that cannot cause infection, i.e. pathogens must be
killed. Some organisms and bacterial spores may survive.
Disinfectants are chemicals that are used for disinfection.
Disinfectants should be used only on inanimate objects.
Uses of Sterilization
1. Sterilization for
Surgical Procedures: Gloves, aprons, surgical instruments, syringes etc. are to
be sterilized.
2. Sterilization in
Microbiological works like preparation of culture media, reagents and
equipments where a sterile condition is to be maintained.
CLASSIFICATION OF METHODS
Sterilization and disinfection are done by:
(A). Physical Agents
1. Heat
2. Radiation
3. Filtration
Antiseptics are mild forms of disinfectants that are used
externally on living tissues to kill micro-organisms, e.g. on the surface of
skin and mucous membranes.
(B). Chemical Agents
In practice, certain methods are placed under sterilization
which in fact do not fulfil the definition of sterilization such as boiling for
1/2 hr and pasteurization which will not kill spores.
STERILIZATION BY HEAT
Heat is most effective and a rapid method of sterilization
and disinfection. Excessive heat acts by coagulation of cell proteins. Less
heat interferes metabolic reactions. Sterilization occurs by heating above
100°C which ensure lolling of bacterial spores. Sterilization by hot air in hot
air oven and sterilization by autoclaving are the two most common method used
in the laboratory.
Types of Heat:
A. Sterilization by moist heat
B. Sterilization by dry heat
A. Sterilization by Moist Heat
Moist heat acts by denaturation and coagulation of protein,
breakage of DNA strands, and loss of functional integrity of cell membrane.
(I). Sterilization at 100°C
1. Boiling. Boiling
at 100°C for 30 minutes is done in a water bath. Syringes, rubber goods and
surgical instruments may be sterilized by this method. All bacteria and certain
spores are killed. It leads to disinfection.
2. Steaming. Steam
(100°C) is more effective than dry heat at the same temperature as: (a)
Bacteria are more susceptible to moist heat, (b) Steam has more penetrating
power, and (c) Steam has more sterilizing power as more heat is given up during
condensation.
Steam Sterilizer. It works at 100°C under normal atmospheric
pressure i.e. without extra pressure. It is ideally suitable for sterilizing
media which may be damaged at a temperature higher than 100°C.
It is a metallic vessel having 2 perforated diaphragms
(Shelves), one above boiling water, and the other about 4" above the
floor. Water is boiled by electricity, gas or stove. Steam passes up. There is
a small opening on the roof of the instrument for the escape of steam.
Sterilization is done by two methods:
(a) Single Exposure for 11/2 hours. It leads to
disinfection.
(b) Tyndallisation (Fractional Sterilization). Heat labile
media like those containing sugar, milk, gelatine can be sterilized by this
method. Steaming at 100°C is done in steam sterilizer for 20 minutes followed
by incubation at 37°C overnight. This procedure is repeated for another 2
successive days. That is 'steaming' is done for 3 successive days. Spores, if
any, germinate to vegetative bacteria during incubation and are destroyed
during steaming on second and third day. It leads to ilia. Sterilization above
100°C: Autoclaving
Autoclaving is one of the most common methods of
sterilization. Principle: In this method sterilization is done by steam under
pressure. Steaming at temperature higher than 100°C is used in autoclaving. The
temperature of boiling depends on the surrounding atmospheric pressure. A
higher temperature of steaming is obtained by employing a higher pressure. When
the autoclave is closed and made air-tight, and water starts boiling, the
inside pressures increases and now the water boils above 100°C. At 15 ib per
sq. inch pressure, 121°C temperatures is obtained. This is kept for 15 minutes
for sterilization to kill spores. It works like a pressure cooker.
'Sterilization holding time' is the time for which the
entire load in the autoclave requires to be exposed sterilization.
Autoclave
is a metallic cylindrical vessel. On the lid, there are: (1) A gauge for
indicating the pressure, (2) A safety valve, which can be set to blow off at
any desired pressure, and (3) A stopcock to release the pressure. It is
provided with a perforated diaphragm. Water is placed below the diaphragm and
heated from below by electricity, gas or stove. Working of Autoclave. (a) Place
materials inside, (b) Close the lid. Leave stopcock open, (c) Set the safety
valve at the desired pressure, (d) Heat the autoclave. Air is forced out and
eventually steam ensures out through the tap, (e) close the tap. The inside
pressure now rises until it reaches the set level (i.e. 15 Win), when the
safety valve opens and the excess steam escapes, (f) Keep it for 15 minutes
(holding time), (g) Stop heating, (h) Cool the autoclave below 100°C, (i) Open
the stopcock slowly to allow air to enter the autoclave
Checking of Autoclave for Efficiency. Methods:
(i) Spores of
Bacillus stearothermophilus are used. Spores withstand 121°C heat for up to 12
min. Strips containing this bacteria are included with the material being
autoclaved. Strips are cultured between 50°C and 60°C for surviving spores. If
the spores are killed the autoclave is functioning properly.
(ii)Automatic Monitoring System.
III. Sterilization
below 100°C
1. Pasteurization.
Pasteurization is heating of milk to such temperature and for such a period of
time so as to kill pathogenic bacteria that may be present in milk without
changing colour, flavour and nutritive value of the milk. Mycobacterium bovis,
Salmonella species, Escherichia coli and Brucella species may be present in
milk. It does not sterilize the milk as many living organisms including spores
are not destroyed.
Methods of
Pasteurization
(i) Flash Method.
It is "high temperature- short time method". Heating is done at 72°C
for 15 seconds.
(ii) Holding Method. Heating is done between 63°C and
66°C for 30 minutes.
2. Inspissation. Inspissation is done between 75°C to
80°C. Inspissation means stiffening of protein without coagulation as the
temperature is below coagulation temperature. Media containing serum or egg is
sterilized by heating for 3 successive days. It is done in 'Serum
Inspissation'.
B.
Sterilization by Dry Heat
Mechanisms. (1) Protein denaturation, (2) Oxidative
damage, (3) Toxic effect of elevated electrolyte (in absence of water).
Dry heat at 160°C (holding temperature for one hour
is required to kill the most resistant spores). The articles remain dry. It is
unsuitable for clothing which may be spoiled.
1. Red Heat.
Wire loops used in microbiology laboratory are sterilized by heating to 'red'
in Bunsen burner or spirit lamp flame. Temperature is above 100°C. It leads to
sterilization.
1. Flaming.
The article is
passed through flame without allowing it to become red hot, e.g. scalpel.
Temperature is not high to cause sterilization.
3. Sterilization by Hot Air
Contra-indication refer to
·
People taking antibiotics
·
Drunk
·
Drugs taken
·
Allergic
·
Using of contact lenses
1 Prevention of infections
·
Avoid sharing
·
Clean sponges
·
Avoid put in lipstick straight onto lips
·
No mascara sharing
·
Clean, sterilise brushes
2 Communication
skills
·
Behaviour properly
·
Good listening skills
·
Verbal communication
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