sensitive test for the detection of fecal and therefore potentially dangerous.
Water and food culture
• Name : Ghazala Shaheen
• Serving as Sr. Technologist 1
• Clinical Microbiology
WATER CULTURE TESTING
Water is one of our most precious & natural
resources without sufficient quantity. Water is
the most abundant compound used by all life.
The requirement for a public water supply are.
1. It shall contain no organism which cause disease
2.It should be clear and colorless.
3.It should be good testing free from odours and
•Full examination of water supply embodies for
time of investigation topographical
,chemical, biological and bacteriological each
having its uses.
• All the above mentioned investigations are
important but we are concerned with
bacteriological examinations which is particularly
important because it still offers the most sensitive
test for the detection of fecal and therefore
TECHNIQUE OF SAMPLING
Sterile bottles should be provided by the
laboratory performing the examination & should be
used exclusively for bacteriological purposes
neutralization of chlorine for low concentration of
chlorine & PH values normally occurring in water
TECHNIQUE OF SAMPLING (contd)…
Sodium thiosulphide added in empty containers
should neutralize up to 5mg/l of free and
combined residual chlorine and as no
significant effect on the coli form of E.Col;
content of unchlorinated water on storage so
it is therefore recommended that at least this
level of thiosulphate should be added to all
bacteriological sample bottles before they are
OPENING & FILLING OF SAMPLE BOTTLES
1. Keep the sample bottle unopened until the moment
it is required for filling.
2. Never rinse out a bottle before taking a sample
loosen the string or rubber band holding the cover in
position. Hold the bottle by the base in one hand &
remove the stopper cover together with the other
3. Retain the stopper & cover in the hand whilst the
bottle is filled & replace them immediately.
4. Finally secure the cover.
BACTERIOLOGICAL EXAMINATION OF
For several reasons monitoring for the pressure of the specific
pathogenic bacteria, viruses and other agents in water is
impracticable & indeed unnecessary for routine control
purposes, any pathogenic microorganism present in water are
usually greatly outnumbered by & in general flora of contaminated
water especially when it is heavily polluted.
Selective media are required for isolation & subsequent
identification of the organism involves biochemical & other tests
for the detection of certain commenced intestinal bacteria
especially E.Coli & other coli form bacteria. Bacterial examination of
water consist of different pathogens. They are
• Total colony count
• Total coli form
• Fecal E.Coli
• Fecal Strept
WATER CULTURE MEDIA
We have used different media for water culture
• TGT For coliform
• EMB For F.E.coli
• Bile For F.Strept
• CMA For Pseudomonas
Food microbiology is on the detection & analysis of
food borne spoilage micro organisms.
Food microbiology is the study of food micro
organisms, how we can identify & culture them, how
they live and how some infect and cause diseases.
DDY JET 1
EDDY JET 2
PROCESSING OF FOOD SAMPLES
Two types of food samples we have process by two
• Raw Food
• Cooked Food
Raw food have processed by poured plate method &
cooked food process by spiral plate method. Important
pathogen which spoil the food cause different food
borne infection & food borne illnesses.
Indicator organisms which cause food born infection are.
• 1. E.coli
E.coli can cause severe cramps & diarrhea.
E.coli leading cause a bloody diarrhea. E.Coli
infection come from
Eating uncooked ground beef.
Drinking contaminated (impure) water.
Drinking unpasteurized (raw) milk.
• Staphylococcus Aurous:
Staphylococcus aurous common cause of bacterial
food borne disease world wide. Symptoms include
vomiting & diarrhea that occur shortly after ingestion
of staphylococcus aurous toxin contaminated food.
Staphylococcus aurous is a leading cause of gastro
enteritis resulting from the consumption of
Salmonella is one of the most common cause of
acute gastroenteritis and is usually found in
poultry, eggs unprocessed milk & in meat and water.
Salmonella bacteria attack the stomach & intestine.
In some serious cases bacteria enter the lymph treats
which carry water & protein to the blood.
• Listeria Monocytogens:-
These are bacterial pathogens & cause food illness. The
disease is called “Listerious”.
It is caused by poor hygiene and easily passed from
person to person & from infected individuals to food
items. It causes an estimated diarrhea, sources
include salad, unclean water& any food handled by
someone who is infected with the bacterium.