Indetification and i solation of Bacteria responsible for food poisoning.

1. Microbiological Quality Analysis of
Drinking water and Food
Training report
on
Presented by
Radheshyam sinha
Reg. non-11504603
M.Sc. Industrial Microbiology
Submitted to

2. Overview of the organization.
Introduction
Scope of the studies.
Aims and Objective
Methodology
Conclusion
Bibliography
Contents

3. Overview of the organization
FARE Labs
possesses world-
class
competencies in
Analytical Testing
and Research &
Development.
OBJECTIVE
OF THE
COMPANY
To become a source of
national pride by
contributing to the world
of scientific and industrial
research and development
in the diverse areas of
chemical, biotechnological
and environmental
technology.

4. Why Food testing laboratories ??
 Food and water microbiology examination laboratories play a vital role in
protecting people health.
 operate as first line of defense.
 Food and water act as vehicle for the transmission of microbial disease (Nkere
et al., 2011).

5. Introduction.
 Food and water is an integral part of our daily lives, and without food and water
, life itself would cease to exist.
 Water is essential for all forms of life and certain human activities.
 In the course of survival, certain living organisms may contaminate water
required for use by others.
 Foods that are consumed daily, has a minimum shelf life and are more prone to
be contaminated by microorganisms resulting in food spoilage which ultimately
lead to diseases of various kind.
 All food should be safe and free from contamination and spoilage at all points
in its journey from its source until it reaches the consumers.
 food-borne illness is a rising cause of morbidity in all countries and the list of
potential food-borne microbial pathogens keeps increasing.
 In India an estimated 4,00,000 children below five years age die each year due
to diarrhea.

6. Scope
 To meet out the challenges in the food processing industry, laboratories play a vital
role.
 The scope of testing activity in laboratories encompasses the quality and safety
attributes.
 agriculture and food products, dairy products, oil seeds, oils, spices and condiments,
animal products, plantation products and flavours, functional foods, processed foods
and beverages

7. Aims and objective
To have an idea of Food testing laboratory.
To identify different problem associated with food
contamination due to microorganism.
To determine quality of the food for public health purposes.
To compare real scenario with the lesson learn in LPU
University.

8. Quality
 Refers to the levels of occurrence of
microorganisms in the final product.
 Indicates the amount of microbial
contaminants it has, a high level of
contamination indicates low quality
of food and its handling more likely
to transmit diseases
 Bacterial count in prepared food and water is
a key factor in assessing the quality and
safety of food.
 If the microbiological testing result is within
the required limits, then the water / food is
said to be microbiological quality for human
consumption (APHA et al. 2012).
 It also reveals the level of hygiene adopted by
food handlers in the course of preparation of
such foods.
It is the combination of attributes or characteristics of a product that
have significance in determining the degree of acceptability of the
product to a user (USDA Marketing Workshop Report, 1951).
What is Microbiological quality of food ??
How to assess this
Quality of food??

9. Necessity of Quality control in food testing laboratory
• A specific activity whose purpose is to monitor a discrete laboratory
task to ensure that it meets a predefined criterion.
• Safety and wholesomeness are the most important attributes of food
quality.
• The lack of quality as it relates to safety and wholesomeness can
result in personal injury, sick-ness or death.
• Food-borne illness is an example of sickness or even death when
unsafe foods are produced and eaten.
• The purposes of quality control is To protect the customers
from dangers (eg contaminated foods).

10. Laboratory analysis is the phase in which a quality
control program is implemented after product is
produced.
Microbiological methods performed on product such as
poultry, red meat, dairy, vegetable or seafood also
requires special instruments and equipment such as:
1. Autoclave
2. Incubator
3. Hot air oven
4. Inoculating loop
5. Vortex mixer / shaker
6. Water bath
7. Heating mantle
8. Hot plate with magnetic stirrer
9. UV chamber
10. Inoculation chamber
11. pH meter
12. Colony counter
13. Microscope
14. Refrigerator
15. Bunsen burner
16. Spirit lamp
17. Micrometer (stage and ocular)
18. Balance (Digital)
19. Thermometer
Laboratory analysis

12. Water is essential for all forms of life and certain
human activities. Water can be uses:
 As an ingredient.
 To convey or transport products.
 To wash foods.
 To make ice and glazed products.
 To clean and sanitize facilities, utensils,
containers and equipment, and
 For drinking.
 In the course of survival, certain
living organisms may contaminate
water required for use by others
Microbial
Analysis of Water

13. Why control water Quality?
Health and survival of man and other organisms
depends on the purity of the water they use.
Different measures are used to access and control
water quality with varying degrees of relevance and
acceptability.

14. Water Quality Assessment
Physical
Chemical
Microbial
Water Quality

15. Offers the most
sensitive test for the
detection of recent
and potentially
dangerous faecal
pollution
Provides a hygienic
assessment of water
quality with high
sensitivity and
specificity
It is important to
examine water sources
frequently by simple
tests rather than
infrequently by more
complicated test or
series of tests

16. Indicator Organisms

17. E. coli
Faecal
Coliforms
Total
Coliforms
Indicator organism

18. Indicator Organisms
Total
Coliforms
Gram-ve,rod shaped, include bacteria that are found in the soil, in water
that has been influenced by surface water, and in human or animal
waste.Not necessarily faecal bacteria
are the group of the total coliforms that are considered to be present
specifically in the gut and feces of warm-blooded animals.Fecal
coliform
is the major species in the fecal coliform group.
E. coli is generally not found growing and reproducing
in the environment
Escherichia coli (E.

19. Sampling from a tap or pump outlet.
 Remove any attachments from tap that may cause splashing.
 Wipe off the dirt from outside the tap.
 Turn on the tap at maximum flow rate and let the water flow for 1-2
minutes.
 Sterilize it for a minute with flame using gas burner, lighter or ignited
cotton wool soaked in spirit.
 Open the tap and allow water to flow at medium rate for 1-2 minutes.
 Open the container for collecting the sample and fill the water by
holding the bottle under the water jet. Leave a small airspace to
facilitate shaking at thetime of inoculation prior to analysis.
 Stopper the cap and label the container.
Sampling

20. Methods for Microbial Analysis of water
 Multiple-tube method.
The Most Probable Number (MPN) method
is applicable to the enumeration of coliforms,
faecal coliforms and Escherichia coli in foods,
food ingredients and water
Test for coliforms
 Presumptive test:
After 24 – 48 hours of incubation, MacConkey
broth tubes (both single strength and double
strength).
Set of Double Strength MacConkey broth tubes
Set of Single Strength MacConkey broth tubes (1ml and
0.1 ml)

21.  Confirmed test:
Positive tubes from presumptive
test were taken and inoculation into
BGB tubes was done. After 48 hours of
incubation at 370C, BGB tubs were
observed as shown in fig.
 Completed test
After streaking a loopful culture
from the positive BGB tubes on the
MacConkey agar, plates were incubated
at 37°C for 24 to 48 hours as shown in
fig-

22.  Faecal coliform Test:
Positive tubes from presumptive
test were taken and inoculation into
BGB tubes was done. After 48 hours of
incubation at 44.50C, BGB tubs were
observed as shown in fig.
 E.coli Test:
Peptone water tube (tubes having
red colored ring indicate positive indole
test i.e. E.coli is present and other tubes
indicate negative indole test i.e. E.coli is
absent.) as shown in fig-

23. Sample 10ml 1ml 0.1
Treated drinking-
water
5 5 5
Partially treated
drinking water
5 5 5
Treated water in
the distribution
system
5 5 5
Typical sample volumes and number of tubes for multiple fermentation tube

24. MPN statistical table
Combination of MPN index /100ml 95% confidence level
Upper lower
0 0 0 < 2 - -
0 0 1 2 1 10
5 3 0 80 30 250
3 1 0 11 4 29

25. Guidelines of Bacteriological quality of drinking water.
Water sample Organisms Guidelines
All water intended for drinking. E. coli or thermotolerant coliform
bacteria
Must not be detectable in any 100
sample.
Treated water entering the
distribution system
E. coli or thermotolerent coliform
Bacteria
Must not be detectable in any 100
sample.
Total coliform bacteria Must not be detectable in any 100
sample
Treated water in the distribution
system
E. coli or thermotolerent coliform
Bacteria
Must not be detectable in any 100
sample.
Total coliform bacteria
Must not be detectable in any 100
sample. In the case of large supplies,
where sufficient samples are
examined, must not be present in
of samples taken throughout any 12
month period.

26. Why microbiological analysis of foods??
One of the most important reasons for analyzing foods from both the
consumers and the manufacturers standpoint is to ensure that they are safe.
A food may be considered to be unsafe because it contains harmful
microorganisms (e.g., Listeria, Salmonella)
Foods contaminated with pathogenic microorganisms do not look bad
,taste bad or smell bad.
Disease that result from contaminated food are of two types
 Food borne intoxication
 Food borne infection
Most common symptom associated with food borne illness is diarrhea,

27. Methods for Microbial
Analysis Microbial
analysis
Quantitative
analysis
Qualitative
analysis
1.Aerobic
plate count
(APC)
2.Yeast and
Mold count
3. Total
Coliform
count
Detection of
• E.coli
• Salmonella
• Staphylococcus aureus
• Clostridium perfringens
• Listeria monocytogenes

28. Sample collection
 A sample, consisting of a specified number of sample units (usually five) drawn at random
from each lot, shall be taken.
 Each sample unit shall consist of at least 100 ml or g.
 Collect original unopened container wherever possible.
 If the product is in bulk, several sample units can be collected from one container, while
ensuring that the total number of sample units are not collected from one container..
 Employ aseptic techniques in collecting the sample units.
 Keep the sample unit refrigerated (0-40C) or frozen, depending on the nature of the
product, during transport.
 Do not allow sample units that are usually frozen, to thaw during shipment. The samples
of foods received in the laboratory should be kept in a frozen condition, in the refrigerator
or at room temperature, according to the type of material till required for examination. The
samples should be examined as soon as possible preferably within 6 hours of their receipt.

29. Quantitat
ive
analysis

30. Aerobic Plate Count
 This method is applicable to the enumeration of viable aerobic
bacteria (psychrophilic, mesophilic and/or thermophilic
bacteria) in foods. Figure shows the growth of bacteria on Plate
Count Agar.
 The significance of APCs, however, varies markedly according
to the type of food product and the processing it has received
 Procedure
 Mix 10g sample into 90ml maximum recovery diluent
 Prepare serial dilution of 10-1,10-2,10-3,10-4
 Inoculate 1 ml of each dilution into PCA
 Incubate at 30◦C for 72 hour

31. Sl.No. food Sample CFU per gram or
CFU per ml
1 Cheese food 441
2 Pizza 495.45
3 Cookies 141
4 Ice cream 44091
5 Pasteurized milk 2286
Sl.No. food Sample CFU per gram
or CFU per ml
1 Sandwiches 1238
2 Soups and soup bases 670
3 Meat sauces 1108.5
4 Fish sauces 1018.6
5 Vegetable sauces 958.7
Level-1 Ready-to-eat food Tested in the
Laboratory
Level-2 Ready-to-eat food Tested in the Laboratory
Level 1: foods in which all components of the food have been cooked in the
preparation of the final food product. Microbial counts should be low.
Level 2: foods which contain some components that have been cooked and then
further handled (stored, sliced or mixed) prior to preparation of the final food.
Three levels of APC based on food type and the
processing/handling the food has undergone

32. Test
Microbiological Quality (CFU per gram)
Satisfactory Marginal Unsatisfactory Potentially
Hazardous
Standard Plate
Count
Level 1 <104 <105 ≥105 -
Level 2 <106 <107 ≥107 -
Level 3 N/A N/A N/A -
Guideline levels for determining the microbiological quality
of ready-to-eat Foods
Level 3: APCs not applicable. This applies to foods such as fresh fruits and vegetables (including
salad vegetables), fermented foods and foods incorporating these (such as sandwiches and filled
rolls). It would be expected that these foods would have an inherent high plate count because of the
normal microbial flora present.

33. Yeast and Mold Count
 This method is applicable to the enumeration of viable
yeasts and molds in foods and food Ingredients, It may
also be used to confirm the viability of apparent yeast and
mold material Scraped from food plant equipment and
the manufacturing environment
 Both yeasts and molds cause various degrees of
deterioration and decomposition of foods.
 Molds, such as Aspergillus, Rhizopus, and Penicillium,
are responsible for the spoilage of cured meats. Some
molds, in the right conditions, produce mycotoxins.
Aspergillus flavus (A. flavus) and A. parasiticus are
two molds of importance as potential foodborne
pathogens.
 They are involved in different forms of diseases,
including allergies to fungal antigens, production of
toxins, or direct invasion of hosts (McGinnis, 1996).
Yeast colonies are usually will be characterized
as smooth, moist, elevated or surface colonies,
figure shows the yeast grows on CYG agar.

34. Mold colonies are easily recognized by their profuse growth of
hyphae, figure below shows the growth of Mold on CYG agar
Tea Rice
Tomato B
flavour
Procedure
 Mix 10g sample into 90ml maximum recovery diluent
 Prepare serial dilution of 10-1,10-2,10-3,10-4
 Inoculate 1 ml of each dilution into Chloramphenicol
Yeast Extract Agar(CYGA)
 Incubate at 25◦C for 3-5 days.

35. Enumeration of Yeast and Mold count of
Beverages and Ready-to-eat foods (Prevention of
food adulteration roles, 1956)
Sl.No. Sample Y/M per gm/ml Limit
Yeast and Mold in Fresh squeezed juice
1 Apple Juice 15.72
Not more
than
2.0cfu/ml
2 Aloe Vera Juice 10.66
3 Lemon-Lime
Spritzer
50.55
4 Tomato 25.64
Yeast and Mold in food
1 Bread 50.9 shall be
absent in 0.1
g of the
product
2 Dried lemon 110.54
3 White rice 90.45
4 Aata 115.5

36. Total coliform count
 Total Coliform bacteria are a commonly used bacterial
indicator of sanitary quality of foods and water.
 They are defined as rod-shaped Gram-negative non-spore
forming and motile or non-motile bacteria which can
ferment lactose with the production of acid and gas when
incubated at 35–37°C.Figure shows the growth of coliform
on crystal violet neutral red bile lactose agar (VRBLA).
 Procedure
 Mix 10g sample into 90ml maximum recovery diluent
 Prepare serial dilution of 10-1,10-2,10-3,10-4
 Inoculate 1 ml of each dilution into VRBL agar
 Incubate at 37◦C for 24h.
Growth of coliforms on VRBL
agar

37. Confidence limits for the estimation of small numbers of
colonies
Number of Coliforms Confidence limits at the 95% level
Lower limit upper limit
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
<1
<1
<1
1
2
2
2
3
4
4
5
6
7
7
8
02
04
05
06
09
10
12
13
14
16
18
19
20
21
23
Sl.No. Sample CFU per gram or CFU
per ml
1 Ice-cream 673.2
2 Pasteurized milk 350.9
3 Fruit Juices 531.5
4 Corn syrup 500.62
Total coliform count of food sample

38. Qualitative
Analysis

39. 1.E.coli
2.Salmonella
spp.
3.Staphylococcus
aureus
4.Clostridium
perfringens
5. Listeria
monocytogenes
Microorganism
responsible for food
poisoning, Such as

40. E.coli
 E. coli is a gram-negative, motile, nonsporulating, rod-shaped,
facultative anaerobic bacterium, present in the lower intestinal tract of
humans and warm-blooded animals and birds (Ray, 2004).
 serves a useful function in the body by suppressing the growth of
harmful bacterial species and by synthesizing appreciable amounts of
vitamins.
 pathogenic E. coli infection is of concern in raw ground and non-intact
beef products. There are specific regulatory requirements for the
reduction of E. coli O157:H7 in raw ground and non-intact beef
products.
 The pathogen of primary concern is E. coli O157:H7, which is a Shiga-
toxin-producing E. coli (STECs).
 E. coli O157:H7 causes hemorrhagic colitis (HC).All people are
believed to be susceptible to HC.
E.coli shows metallic shiny colonies on EMB agar
E.coli at 44°C in MacConkey broth medium:
Positive with acid and gas.

41. Procedure
 25g sample + 200ml o.1% peptone was taken and
homogenized properly
 Transfer 10ml sample + 10 ml MB(double strength)
& 1ml sample + 10ml MB(single strength)
 Incubated all the inoculated media at 370C overnight
 If MB medium is positive then streaked on EMB
agar,Tergitol-7 agar and MacConkey agar.
E.coli produced Pink colonies surrounded by a zone of acid
precipitated bile on MacConkey agar
E.coli produce yellow colonies with yellow zone on
Tergitol-7
Biochemical Test Positive or Negative reaction
TSI hydrogen sulfide production -
Indole reaction +
Voges-Proskauer reaction -
Methyl red reaction +
Simmons citrate utilization -
Growth at 44°C in MacConkey
broth medium
+

42. Salmonella spp.
 Salmonella is a rod-shaped, generally motile, non-spore forming, Gram-negative
bacterium.
 Salmonella are considered among the most important enteric foodborne pathogens
whose presence in the food constitutes a severe health hazard.
 potentially present in most raw meats
 In food processing, Salmonella infection is of concern in raw poultry, swine, and ready-
to-eat products.
 Salmonella are heat and acid-sensitive.
 Salmonella not only survives drying, but also becomes more heat-resistant with drying
and is more of an issue in non-fermented dried meats, such as jerky, and whole meat
cuts. Salmonella remains viable for a long time in frozen foods.
 Many outbreaks of human illness have been associated with the consumption of raw or
inadequately heat treated milk or their dairy products (Ellis et al., l998)

43. Who can get Salmonella???
 You can get Salmonella from eating a variety of foods. Salmonella can
be found in a variety of foods including chicken, vegetables, eggs, fruits,
sprouts, beef, pork — and even processed foods, such as frozen pot pies
and stuffed chicken entrees. Contaminated foods usually look and smell
normal, which is why it is important to detect this organism from food.
 Salmonellosis is a type of food poisoning caused by the Salmonella
enterica bacterium.
 Every year, Salmonella is estimated to cause one million foodborne
illnesses in the United States, with 19,000 hospitalizations and 380
deaths. Most persons infected with Salmonella develop diarrhea, fever,
and abdominal cramps 12 to 72 hours after infection.

44. Salmonella produce black
colonies on Bismuth sulfite agar.
Salmonella appears as red to pink-white
colonies surrounded by a red zone in
the on Brilliant Green Agar(BGA).
Salmonella appear as pink (lactose non-fermenting
colonies) with black center (due to H2S production)
on Xylose Lysine Deoxycholate (XLD) Agar
 25g sample + 225 ml of buffered peptone water and mix
by shaking, then incubate at37◦C for 16 hour.
 If turbidity observed in BPW, Transfer 0.1ml of culture to
10ml Rappaport Vassiliadis medium.
 If turbidity observed,then Streak on BGA, XLDA and
BSA, so that well isolated colonies will be obtained
Procedure
After incubation at first selective- enrichment, RV
medium

45. Biochemical Test Positive or Negative
reaction
TSI glucose (acid formation) +
TSI glucose (gas formation) +
TSI lactose -
TSI sucrose -
TSI hydrogen sulfide
production
+
L-lysine decarboxylation +
Indole reaction -
Voges-Proskauer reaction -
Salmonella generally show the reactions given in the following table

46.  Staphylococcus aureus is a Gram-positive bacterium
(coccus), which appears in clusters resembling grapes under
the microscope. It is a non-motile, non-spore forming
facultative anaerobe that can grow with or without oxygen
 Source meat and meat products, poultry, and egg
products .
 associated with mucous membranes (nose and throat) and is
commonly found on the skin and hair of healthy humans
and animals.
 Contamination of ready-to-eat foods with coagulase-
positive staphylococci is largely as a result of human
contact.
 contaminate meat from the animal skin or tissue during
slaughter (especially during hide removal and gutting).
Staphylococcus aureus
 It becomes a problem when competitive microbes are
removed by cooking or inhibited by high-salt levels.
 Staphylococcal food poisoning is caused by the
consumption of a heat-stable enterotoxin produced as
a byproduct during the growth of certain strains of S.
aureus.
 MID - Greater than 100,000 cells per gram (less than
1.0 microgram of enterotoxin A)
 It should not be detected in 25gm of any types of food.
If detected, considered as potentially hazardous and
may result in food borne illness if consumed.

47. Procedure
 10g sample + 90ml 0.1% peptone was taken and
homogenized properly.
 Then 10 ml of aliquot was transfer in to cooked
salt medium tube and streak on Baird-Parker
medium (BPA).
 Incubate the salt medium at 37°C overnight and
the inoculum in Baird-Parker medium at 37°C for
at least 30 hours.
 From the salt medium, make subcultures on
Baird-Parker agar medium and incubate for 30
hours.
S.aureus produces black colonies on BPA and A clear zone
and grey-black colonies on this medium are diagnostic for
coagulase positive Staphylococci.
Coagulase react with prothrombin in
the blood, forming a complex named
staphylothrombin which causes
blood to clot by converting
fibrinogen in to fibrin. This
mechanism protect bacteria from
phagocytosis.

48. Clostridium perfringens
 Anaerobic, gram-positive rod and produce lecithinase on
egg-yolk medium
 It can be present in two forms, vegetative cells and
spores. Illness is caused when the vegetative cells are
ingested
 Intoxication is often caused by eating temperature-
abused leftovers. If the food is eaten without adequate
reheating, C. perfringens enters the small intestine and
synthesizes enterotoxins.
 The vegetative cells are killed by heat applied during the
production of RTE foods. However, the spores are heat
resistant
 Source cooked meat and poultry
dishes, beans.
 MID greater than 1,000,000,000 cells
(108 )
 It should not be detected in 25gm of
any types of food. If detected,
considered as potentially hazardous
and may result in food borne illness if
consumed.

49. Procedure
 25g sample + 200ml 0.1% peptone was taken and
homogenized properly.
 Then 10 ml of aliquot was transfer in to cooked meat
medium tube.
 the inoculated tube was heated in a steamer at 100°C
for one hour and incubated anaerobically overnight at
37°C.
 An aliquot of the specimen is also inoculated directly
on to blood agar medium and the egg-yolk medium
(Willis and Hobbs Medium with Neomycin) and
incubated in an anaerobic jar at 37°C overnight.
 Subcultures are made from the growth in medium on to
two the solid media and incubated in an anaerobic jar
at 37°C overnight.
Lecithinase production on egg yolk medium
Lecithinase is a type of phospholipase that acts
upon lecithin.
(A positive lecithinase test is noted by the
appearance of a white, opaque, diffuse zone that
extends into the medium surrounding the colonies).

50. Listeria monocytogenes
 rod-shaped, non-spore-forming, Gram-positive
bacterium
 It is motile and can grow in cool (temperature
range of 0-45 ˚C)
 large proportion of uncooked meat, milk, egg,
seafood’s and fish, as well as leafy vegetables
contain Listeria monocytogenes (Ray, 2004).
 ability to grow in many foods at refrigerated
temperature.
 helps the organism to reach from a low initial
level to an infective dose level during storage of
refrigerated foods
 Listeriosis occurs among the elderly, pregnant
women (outcome-spontaneous abortion, premature
delivery)
 diabetics, people on kidney dialysis, and the
immunocompromised(bone marrow transplant
patients, cancer patients, etc. can also suffer from
listeriosis.
 Source ready-to-eat (RTE) hot dogs, deli meats,
pâté and meat spreads, fermented raw meat
sausages, and raw poultry and meat (all types)
 MID - Unknown. May vary with the strain and
susceptibility of the individual.

51. Procedure
 25gm of sample + 225ml half Fraser broth was
taken. Then it was properly homogenized.
 Incubated at 300C for 24h
 If turbidity is observed, then Streaked on Oxford
and PALCAM agar, and incubate at 300C for 48h.
 0.1ml incubated (HFB)Pre-enrichment culture
was transferred in to 10 ml Secondary-Fraser
broth
 Incubate at 370C for 48h.
 Streaked on PALCAM and Oxford agar.
 Observed characteristic colonies on selective
media.
The colonies are green and surrounded by a black zone
on PALCAM agar
The colonies are Greenish sheen with black halos and
sunken Centre on Oxford agar.

52. Species Haemolysis Production of acid
Rhamnose Xylose
Listeria
Monocytogenes
+ + -
Biochemical Identification of Listeria spp
Control Control

53. Conclusion
 Food safety should be considered as an integral part of the primary health care delivery system.
 Health authorities in India should strengthen considerably the present system in to an effective
foodborne disease surveillance system.
 There is a need to strengthen the work already undertaken and further improve interdisciplinary
approaches in order to tackle public health issues and curb economic losses.
 This will also allow policy makers to design appropriate preventive strategies to lower the
incidence of foodborne illnesses and reduce the risk of morbidity and mortality in Indian
population.
 To prevent both ongoing transmissions of diseases and similar outbreaks in the future,
strengthening of food safety policies and programs, acquisition of epidemiological data for risk
assessment of foodborne pathogens should be done.

54. Bibliography
 American Public Health Association. 1984. Compendium of Methods for the
Microbiological Examination of Foods, 2nd ed. APHA, Washington, DC.
 Indian Standard (IS): 1622.1981
 Indian Standard (IS): 5401. (Part1).2002
 Indian Standard (IS):5887 (Part 1):1976
 Indian Standard (IS):5887 (Part 2):1976
 Indian Standard (IS): 5887. (Part 3):1999
 Indian Standard (IS): 5887 (Part 4):1999
 Indian Standard (IS):14988 (Part 1): 2001