Sources of Micro-organisms
Soil - Greatest
variety of micro-organisms
Water - Not
only natural flora but also from
other sources
Air - All the microorganisms present in air come from other sources
Animal- Include
surface flora, the flora from
respiratory and gastro-intestinal tracts
Types of Microorganisms
µ Mould
µ Bacteria
µ Viruses
µ Protozoa
Molds - Common name applied to certain
filamentous fungi
è Multicellular,
Cottony Appearance, Seprophytes or Parasites
è Draught
resistant
è Grow
well at ordinary temp.
è Opt.
Temp – 25-30oC
è Aerobic
è pH 2-8.5
BACTERIA
Ø Very
small organisms
Ø Unicellular
Ø Having
no root, stems, chlorophyll.
Ø Need
more water for their growth as compared to molds
Ø Aerobic
as well as anaerobic
Ø Optimum
pH – 6-7
CLASSIFICATION
- Psychrophilic:
Capable of growing at the temperature – between 3-30oC.
- Mesophilic:
These, which can grow between 20-45oC. Bacteria causing animals
and human diseases are mostly mesophilic. Opt. Temp- 36-37oC.
- Thermophilic:
Higher temperature, Opt. Tem-55-65oC.
IMPORTANCE OF BACTERIA
Pathogenic: Infectious Food poisoning
Infectious: Disease causing bacteria are carried
to the host through food and water.
Typhoid
fever
Tuberculosis
Cholera
Food
Spoilage: Causing
food spoilage
Not associated with human diseases
Pseudomonas, Alcaligens, Micrococcus etc.
Typical Coliforms
Salmonella
Features:
q Salmonella .
is a rod shape, gram negative, non
spores formers
q Types
Three impotant types are, S. enteridica S. typhi, S. paratyphi
q S.
enteridica causing gasteroenteritis .
symptoms include, Nausea, Vomiting, Abdominal pain, Diarrhea, Fever, Chills,
Headache, Muscle pains, Blood in the stool
Gastroenteritis
S. typhi, and S. paratyphi
q S.
typhi causes deadly disease typhoid
fever which kills over 600,000 people annually all over the world.
q Transmitted
through food and water.
Symptoms
•
Incubation is 1-2 weeks, duration of the illness is 4-6 weeks.
The patient experiences:
Poor appetite; abdominal pain; headaches;
fever, intestinal bleeding or
perforation, rashes diarrhea or constipation
Typhoid Fever
Infection Causes
q Contaminated
food & water
q Animal
wastes
q Pet
birds
q Reptiles
q Heavily
populated places e.g. schools, colleges, nursing homes
q Immune
suppressed people like Aids, Malaria
q Slaughter
Houses
q Dirty
Kitchens
q Ignorance
of personal hygiene especially after using toilets
Bacteremia
- Infection
of tissues surrounding the brain
and spinal card (meningitis)
- Infection within the bloodstream
(sepsis). This condition occurs,
when Salmonella enter and circulate within an
infected individual’s bloodstream,
Streptococcus aureus
q S.
aureus is gram positive bacteria. Golden grape cluster fruit, and also known as
golden staph
q Found
on skin, hair and nose
q About
20% of the human population are long-term carriers of staph.
q The carotenoid
pigment Staphyloxanthin is responsible for the characteristic golden color
of S. aureus colonies.
Diseases
q Skin
infections like impetigo (crusting of the skin)
q Cellulitis (inflammation
of the connective tissue under the skin.
q Breast
feeding women, mastitis (inflammation or abscess of the breast. which
can release bacteria into the mother's milk.
q Bacteremia or sepsis
(Staphylococcal sepsis is a leading cause of shock and circulatory
collapse, leading to death
q Staphylococcal pneumonia,
q Endocarditis,
can lead to heart failure)
Food Poisoning
q Caused
by eating foods contaminated with toxins produced by S. aureus
q Rapid
and often serious
q Staphylococcal
toxins are resistant to heat and cannot be destroyed by cooking.
q Foods
at highest risk of contamination S.
aureus and its toxin production are mostly associated with raw uncooked foods,
raw milk bakery products
Preventive measures
q Wash
hands with soap before handling and preparing food.
q Do
not prepare food if you have a nose or eye infection.
q Do
not prepare/serve food if you have wounds or skin infections on your hands or
wrists
q Keep
kitchens and food-serving areas clean and sanitized
q For
foods, stored longer than two hours, keep hot foods hot (over 60°C) and cold foods cold (4°C)
q Store
cooked food in a wide, shallow container and refrigerate as soon as possible
C. Botulism:
Ingestion of neurotoxin.
Organism – C. Botulinum, anaerobic, spore formers
Symptoms appear – 12-36 hours,
Mortality – very high
Difficulty in swallowing, speaking,
vomiting, double vision.
Sources of Water
Natural
Rainwater, oceans, rivers, lakes, streams, ponds and
springs are natural sources of water.
Dams, wells, tube wells, hand-pumps, canals, etc,
are man-made sources of water.
Rain Water
Rain water
collects on the earth in the form of surface water and underground water
Surface Water in
the form of oceans, rivers, lakes, ponds
Underground Water
Some of the rainwater seeps through the soil on to
the non-porous rocks below. Sometimes due to high pressure, this water comes
out in the form of springs.
Sources of Water Pollution
Chemical contamination
effluent
from factories, refineries, waste treatment plants etc. that emit fluids of
varying quality directly into urban water supplies. .
Microbiological contamination
1 human and
animal waste through various points at water sources,
2 Sewage
disposal without any treatment,
3 Seepage
from septic tanks and pit latrines
4 Improper
handling and storage of water at the home.
5
Contamination can occur in storage tanks
in buildings due to poor maintenance and
cleaning. Overhead tanks in buildings, if not covered and cleaned properly may be
recontamination during storage.
6
Huge amount of sewage generated by rapid
population growth is collected from the cities and dumped directly into rivers,
ponds.
8
Contamination through open, and non use of latrines, eventually
Spreading the disease through water sources (in the rainy season).
9 In urban
areas, many of the water supply pipes and sewerage lines are laid in the same
place. Sewage can enter to broken water
pipes especially where water supply systems are intermittent.
11 Unhygienic
handling of water during transport or within the home can contaminate previously safe water.
12
Contamination at the source can occur,
especially during monsoon. Human and animal excreta are washed into the source
by rains. This happens when proper drainage and source protection is not in place
GRADES OF THE QUALITY OF DRINKING WATER
SUPPLIES ON THE BASIS OF PERIODIC ANALYSIS
Quality of water
|
Coliforms/100 ml
|
E.coli/100 ml
|
1. Excellent
|
0
|
0
|
2. Satisfactory
|
1-3
|
0
|
3. Intermediate
|
4-10
|
0
|
4. Unsatisfactory
|
>10
|
£ 1
|
Water analysis of Coliforms
Sites
|
Coliforms/100ml Water
|
Pabbi (M.C)
|
250
|
Tarnab Tap Water
|
900
|
Pirpiai Nowshera
|
80
|
Jolozai Nowshera
|
350
|
Akbarpura Water Pump
|
0
|
Akora Khattak
|
1800+
|
Peshawer City (M.C) Tap
|
170
|
Safaid Dheri Pesh.
|
300
|
Hayatabad Phase-3 Pesh.
|
80
|
Tarnab Charsadda
|
1800+
|
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