sterilization and disinfection with chemical agent and safety in laboratory during experiments

1. Sterilization and Disinfection safety in
microbiological laboratory
Presented by –Shalini Singh
Roll Number-09
M.Sc Biotechnology -1st Semester

2. Sterilization and Disinfection
 Destruction or removal of
all forms of microbial life,
including endospores
 Usually done by steam
under pressure
 Destruction of vegetative
pathogens on inanimate
objects
 May make use of physical
or chemical methods.

3. Physical Methods Used to Control Microbial Growth
Methods -Mechanism of Action
Moist heat - Boiling or flowing steam -Protein
denaturation
Autoclaving- Protein denaturation
Pasteurization -Protein denaturation
Dry heat- Direct flaming Burning
contaminants to ashes
Incineration- Burning to ashes
Hot-air sterilization Oxidation
Comment
Kills vegetative bacterial and fungal pathogens
and many viruses within 10 min; less effective
on endospores.
Very effective method of sterilization; at about 15
psi of pressure (121°C),all vegetive cell and their
endospores are killed in about 15 min
Heat treatment for milk (72°C for about 15
sec) that kills all pathogens and most non
pathogen.
Very effective method of sterilization. Used for
inoculating loops.
Very effective method of sterilization. Used for
disposal of contaminated dressings ,and paper
Very effective method of sterilization but
requires temperature of 170°C for about 2 hr

5. Phenol Disruption of plasma membrane,
denaturation of enzymes.
Rarely used, except as a standard of
comparison. Seldom used
as a disinfectant or antiseptic because of its
irritating qualities and disagreeable odor
Phenolics Disruption of plasma membrane,
denaturation of enzymes.
Environnemental surfaces, instruments, skin
surfaces, and mucus and membrane
Halogens Iodine inhibits protein function and is
strong oxidizing agent; chlorine forms
the
strong oxidizing agent hypochlorous
acid,
which alters cellular components.
Iodine is an effective antiseptic available as a
tincture and
an iodophor; chlorine gas is used to disinfect
water; chlorine
compounds are used to disinfect dairy
equipment, eating
utensils, household items, and glassware.
Alcohols Protein denaturation and lipid
dissolution
Bactericidal and fungicidal, but not effective
against endospores
or nonenveloped viruses. When the skin is
swabbed with alcohol
before an injection, most of the disinfecting
action probably
comes from a simple wiping away (degerming)
of dirt and some microbes

6. SAFETY IN Microbiology Laboratories
 All specimens of blood and body fluids should be put in a well-constructed container with a secure lid
to prevent leaking during transport
 All persons processing blood and body-fluid specimens should wear gloves.
 Mechanical pipetting devices should be used for manipulating all liquids in the laboratory. Mouth
pipetting must not be done.
 Laboratory work surfaces should be decontaminated with an ap-propriate chemical germicide after a
spill of blood or other body fluids and when work activities are completed.
 Contaminated materials used in laboratory tests should be de-contaminated before reprocessing or
be placed in bags and dis-posed of in accordance with institutional policies for disposal of infective
waste
 All persons should wash their hands after completing laboratory activities and should remove
protective clothing before leaving the laboratory.