This document discusses hygienic aspects of various foods and establishes microbiological standards. It emphasizes that everyone in the food chain has a responsibility to ensure food is safe for consumption. Proper hygienic practices from production to consumption are vital to avoid foodborne illness. The document then examines hygienic practices specifically for milk, cream, butter, ice cream, cheese and milk powder. It establishes microbiological specifications and limits for different foods to assess safety and processing hygiene. The principles of determining specifications are also outlined.

1. HYGIENIC ASPECTS OF VARIOUS
FOODS
DEPARTMENT BIOTECHNOLOGY
(M.TECH IN ANIMAL BIOTECHNOLOGY)
Mununeh Hailu
May 2018

2. • People have the right to expect the food they eat
to be safe and suitable for consumption. Out
breaks of food born illness can damage trade and
tourism, and lead to loss of earnings, un
employment and litigation. Due to dramatic
increase in the international trade and foreign
travel, make the spread of illness around the
world. Effective hygiene control, therefore, is a
vital to avoid the adverse human health and
economic consequences of food borne illness and
food spoilage.

3. • Hygiene must be maintained in the food chain
from the primary production to final
consumption. Everyone including the farmers,
growers, manufacturers, processors, food
handlers and consumers has a responsibilities
to assure that food is safe and suitable for
consumption.

4. • Food industry should apply the hygienic practices in
food safety:
1. To provide food that is safe for consumption
2. To maintain confidence in internationally traded food
3. To insure that food is suitable for human use
4. To protect the health of the workers in food plant
5. To enable the consumers to protect their food from
contamination and growth/survival of food borne
pathogens by storing, handling and preparing it
correctly.

5. • At room temperature, milk can be stored only for 3
hours immediately after milking. The shelf life of
milk can be extended to 24 hours by cooling to 50C.
Its shelf life is further extended to 4 to 7 days by
pasteurization. By UHT treatment, the shelf-life is
extended to few months.
Hygienic aspects of milk:
1. After reception of raw milk, prompt chilling should
be carried, out immediately to temperature of 50C.
2. Use of clean strainer.
3. Proper maintenance of pasteurization temperature
4. No milk residues should be lift after CIP is done
5. Proper sanitization of crates.

6. 6. Avoid rupturing of milk pouches during
handling.
7. Control of air temperature in the coolers.
8. Proper flushing of vending machine with hot
water.
Hygienic aspects of cream:
1. Use the milk of good quality
2. Adequate heat treatment of milk.
3. Final cooling of cream in tank to 50C.
4. Proper storage of cream at 50C or less.

7. Hygienic aspects of butter:
1. Proper pasteurization of cream to destroy the
microbes.
2. Multiplication of psychrotrops can be prevented
by efficient cooling at law temperature (3-50C).
3. Just prior to use, churn should be sanitized with
200 mg/liter chlorine solution. Most of bacteria
in cream are drained in buttermilk but molds are
retained in the butter. To control the molds,
regular cleaning of butter churn is essential.
4. Blending should be avoided as it increases
microbial count in butter.

8. Hygienic aspects of ice cream:
1. Sugar can be a major source of yeasts, molds and
bacterial spores. It is advisable to use the sugar
having mesophilic count of less than 20; and yeasts
and molds count should be less than 1.0 per gram.
2. Fresh and frozen fruits should be checked for
yeasts.
3. Nuts may contain molds and therefore, nuts should
be sterilized with ethylene oxide an CO2 at the ratio
of 1:9.
4. Air can be potential source of organisms and hence,
only filtered air should be incorporated in ice cream.
5. Packaging materials should be effectively sanitized
before use, since they are good source of fungi.

9. Hygienic aspects of cheese:
1. High quality of raw milk should be used.
Bactofugation of raw milk at 10,000 to 20,000
rpm can reduce bacterial count by 99.98 per
cent.
2. Good, active starter cultures should be added
@1 per cent to milk and care must be taken to
avoid microbial contamination.
3. Pressing of cheese is to be supervised by
experienced personnel.
4. Pipelines and other utensils be thoroughly
cleaned and sanitized each day. Pseudomonas
contamination.

10. Hygienic aspects of milk powder:
1. High bacteriological quality of raw milk should be
used.
2. Roller drying is effective as it kills most of the
microbes.
3. Evaporators should be properly cleaned and
sanitized as they may be the potential source of
microbial contamination.
4. Filtered air should be supplied for the driers,
conveyors, cooling and air sweeping processes.
Therefore, filter pads need periodical cleaning to
remove accumulated dust.
5. Drying room should be maintained in highly
sanitary condition to prevent contamination.

11. 6. All vacuum pan, pipelines, concentration tanks,
packaging room and storage containers should be
properly cleaned and sanitized.
Microbiological specifications/standards of various
foods:
• Microbiological standards have been proposed from
time-to-time to ensure food safety. When a food
poses a health hazard, microbiological examination
should be made, hazards identified and
specifications established,.
• Standards for specific pathogens have been
proposed either by fixing maximum permissible
limits per unit (gram, ml or cm2) or by testing
presence or absence of the organism in a given unit
of food.

12. e.g. S. aureus or Salmomella spp; respectively.
Generally, the decisions on the acceptability of
food lots are based on the examination of one
or few samples taken from the batch.
Microbiological standard: This refers to a criterion
incorporated in a law or regulation, controlling
foods produced, processed or stored in, or
imported into the area of jurisdiction of the
regulatory agency.
Microbiological criterion: This denotes a
microbiological value established by use of
defined procedure and applied in acceptance of
sampling of food.

13. • Microbiological specification: The microbiological
criterion that forms the conditions of acceptance
of a specific food or food ingredient by a food
manufacturer or private or public purchasing
agency.
• Microbiological limit: This denotes a criterion
recommended by an authority for adoption in
specific region.
• Microbial guideline: This is a suggested scheme by
a group of experts or body independent of the
producer or the commodity.
• International commission on microbiological
specification for foods has suggested 2 and 3 class
sampling plans

14. II. Two class plan: These denote two attributes,
i.e. presence or absence of an organism in a
given sample unit. It is applied to more
hazardous type of organisms like C. botulism.
According to this plan, a lot can be either
accepted or rejected on the basis of presence or
absence of an infections or toxigenic agent.
II. Three class plan: This plan has three attributes
and can divide a lot into 3 categories
a. Acceptable b. Unacceptable c. Marginally
acceptable

15. Principles of determine specifications:
When a microbiological specification or criterion is
to be determined, following points need to be
kept in mind.
1. These should be based on real observations
(surveys).
2. It should be cheap and simple to opt.
3. Proposed specifications should be able to assess
expected storage life of the commodity,
4. It should be able to evaluate hygienic conditions
of processing.
5. The proposed criterion should be capable of
eliminating or minimizing health hazards.
6. Separate specifications should be formulated for
separate products.

16. 7. It should describe the sampling scheme along
with the analytical methods.
8. It must define the number and size of sample
units to be examines.

17. Microbiological Limits for meats, poultry, egg and sea foods
Type of Meat SPC Colifor
m
E.
coli
Salmonel
la
Clostridiu
m
1. Raw Meat
2. Frozen Meat
3. Beef
4. Chilled raw Meat
5. Ground Meat
6. Processed cooked Meat
7. Fresh Pork Sausage
8. Pork trimmings
9. Communuted Game meat
10.Cooked meat products
11. Cooked beef
12. Chilled and frozen raw
poultry
13. Dried, frozen whole egg
14. Frozen cooked sea foods
<106
< 107
<106
<106
<106
<106
-
-
-
<106
-
107
-
105
A
<104
<102
-
-
-
-
-
-
-
40
-
103
-
A
104
A
-
A
10
2.0
2.0
2.0
<10
-
-
-
20
A
A
A
A
A
A
A
A
-
A
A
-
-
-
A
A
A
A
A
A
-
A
-
-
-
-
-
-

18. Microbiological standards of milk and milk
products:
Raw milk
Grades SPC Coliform
(1:100)
• Very good < 200,000 Absent
• Good 200,000-1,000,000 Absent
• Fair 1000,000-5,000,000 Absent
• Poor >5,000,000 Absent

19. B. Pasteurized milk
Test Requirement
• SPC maximum 30,000 Cf/ml
• Coli form count absent in 1:10 dilution
C. Raw cream
Grades SPC
• Very good < 4000, 000
• Good 400,000-2,000,000
• Fair 2,000,000-100,000,000
• Poor > 1,000,000,000

20. D. Pasteurized cream
Grade SPC Coli form
count
• Satisfactory < 60,000 <10
E. Butter
Yeast and mould count/ml Quality
• <20 Good
• 21-50 Fair
• 51-100 Poor
• >100 Very poor

21. F. Ice cream: Limit
• SPC (per gram) Not more than 250,000
• Coli form count (per gram) Not more than 90
G. Condensed milk
Test Limit
• SPC (Per/gram) 500
• Coliform Negative
• Yeast and mould count 10

22. H. Milk Powder:
Type of test Limit
• Total bacterial count (CFU/gram) 40,000
• Coliform count Absent in 0.1gram
• Salmonella Absent in25gram
• Staphylococcus aureus Absent in 0.1gram
• Shigella Absent in 25gram

23. I . Assessing the sterility of utensils/equipments:
Grade Rinse Method Swab Method
Colony count/ liter Colony count/ 900 sq.cm
capacity of can area of equipment surface
Satisfactory <1000 <5000
Fairly satisfactory 1000-5000 5000-25,000
Unsatisfactory >5000 >25,000