About Pasteurization Process for Dairy products, Its very helpful knowing about Pasteurization

1. Presenting by:
Yousuf Khan Durrani

2. • Pasteurization is the process of heating a liquid
below the boiling point to destroy
microorganisms.
• In general, the process of heating of each and
every particle of milk at a particular temperature
for defined time.

3. • Louis Pasteur (December 27, 1822 –
September 28, 1895)
• Was born in Dole, France.
• Was a French biologist, microbiologist and
chemist.
• He was well known for his discoveries of the
principles of vaccination, microbial
fermentation and pasteurization.
• He is remembered for his remarkable
breakthrough in the causes and prevention
of diseases.
• His discoveries have saved many lives ever
since.

4. • In 1860s French wine industry was in trouble due to wine spoilage.
• At that time Pasteur was working at the University of Lille.
• Pasteur examined spoiled wine under microscope.
• He finally reached that conclusion of Microorganisms similar to the
bacteria responsible for lactic acid and acetic acid fermentations.
• Pasteur then discovered that a brief heating at 55-60°C would destroy
these microorganisms and can preserve wine for long periods.
• In 1886 German chemist F. Soxhlet adapted the technique for
preserving milk and reduce milk transmissible diseases.

5. • On the basis of Temperature and Time combination following are the types of
Pasteurization
Types of Pasteurization Time Temperature
Low Temperature Long Time (LTLT) : Vat Pasteurization 30 min 63°C
High temperature Short Time (HTST) : Flash
Pasteurization
15 sec 72 °C
Higher-Heat Shorter Time (HHST) 1 sec 89 °C
Higher-Heat Shorter Time (HHST) 0.5 sec 90 °C
Higher-Heat Shorter Time (HHST) 0.1 sec 94 °C
Higher-Heat Shorter Time (HHST) 0.05 sec 96 °C
Higher-Heat Shorter Time (HHST) 0.01 sec 100 °C
Ultra Pasteurization (UP) 2 sec 138 °C

6. 1. To increase Milk safety by:
• Pathogen destruction
• Maintain originality of Milk.
2. To increase Life of Milk by:
• Almost kills all microbiological
spoilage microbial agents.
• Deactivates enzymatic activity
which affect quality and shelf life
of product.

7. • In Dandy we are using modified HTST
pasteurization technique having following
combinations:
1. 80°C to 85°C for 30 Seconds: For ice cream products.
2. 90°C to 95°C for 30 Seconds: Stirred yoghurts.
3. 90°C to 95°C for 320 Seconds: For fermented dairy
products
4. 90°C to 95°C for 30 Seconds: For juices, nectars, fruit
drinks and flavored drinks.

8. On the basis of structure and design we are
using two types of Pasteurizers in our
facility:
1. Tubular pasteurizer:
• The Tubular Pasteurizer can be
used for juices, soft drinks, tea and
coffee drinks, and water.
• In Dandy we are using for Juices,
fruit drinks and Sugar based drinks.
• Occasionally for Low viscous milk
product.
2. Plate heat exchanger pasteurizer:
• In Dandy we are using this type of
Pasteurizer for Milk and Milk
products.
• Fermented dairy products, and
• Ice cream mixes.

9. • Following are the stages
involved in-process of
pasteurization:
• Float Controlled Balance tank
• Feed pump
• Regenerative heating (R1 &
R2)
• Homogenization
• Heating
• Flow diversion valve (FDV)
• Holding
• Regenerative cooling (R2 &
R1)
• Cooling by chilled water or
brine

10. • Maintains a constant flow of milk
for feeding the pump.
• also receives milk diverted by
FDV (if diverted).
• Float in tank maintain level of
balance tank and prevents
overflow of milk.

11. • Centrifugal pump with a flow control
device to ensure constant output, after
FCBT is used.
• Rotary positive pump can be used
between the regeneration and heating
sections.
• Is used to maintain constant flow of milk
throughout process.

12. • To partially heat raw chilled incoming milk.
• Incoming milk partially and indirectly heated by the heated outgoing milk
(milk-to-milk regeneration).
• This adds to the economy of the HTST process, as the incoming milk
requires less heating by hot water to raise its temperature to pasteurization
temperature in the heating section.

13. • Homogenization is an entirely
separate process that occurs during
pasteurization in most cases.
• The purpose of homogenization is
to break down fat molecules
in milk so that they resist
separation.
• Without homogenization, fat
molecules in milk will rise to the top
and form a layer of cream.

14. • The preheated milk from regeneration section passes through
heating section of HTST.
• Where it is heated to 72°C or more with the help of hot water
from hot well.
• Thereafter, the heated milk enters into the holding section via
FDV (plates/tube).

15. • This diverts the milk before holding section. If the milk is not properly
heated at specified temperature.
• Automatically diverted by the FDV back to the Float Controlled
Balance Tank (FCBT) for reprocessing.
• It is usually operated by air pressure working against a strong
spring.
• Very helpful to insure proper pasteurization

16. • The holding tube ensures that the
milk is held for a specified time, not
less than 15s. at the pasteurization
temperature of 72°C or more.
• Designed to get specified time as
per the flow of product in system.

17. • The pasteurized hot outgoing milk is partially and indirectly cooled
by the incoming cold milk (milk-to-milk regeneration).
• This again adds to the economy of the HTST process. In fact, when
pre-cooled (raw) milk is received, regeneration efficiency is 90%
and above which obviates cooling using well water altogether.

18. • The partially chilled milk from regeneration section passes through chilling
section of HTST.
• Where it is chilled to 10°C or less with the help of chilled water IBT.
• Thereafter, the chilled milk passes to storage tanks.

19. • Following are the direct
or indirect requirements
for the pasteurization:
1. Filters
2. Control panel
3. Automatic control devices
4. Steam pressure controller
5. Water temperature controller
6. Milk temperature recorder
7. Hot water and
8. Chilled water

20. • Bactericidal effect: All of the pathogens are inhibited:
• Mycobacterium tuberculosis (63°C 30 min)
• Coxiella burnetti (72 °C 15 sec)
• Reduction of creamy layer
• Inactivation of phosphatase enzyme of the cream layer
• Pasteurization has a small effect on the vitamins naturally found in milk.
• Whiteness of raw milk & pasteurized milk differs
• Fruit juices – Main problem is color deterioration by enzymic browning (poly
phenol oxidase).
This browning reaction promoted by the presence of oxygen.
In fruit juice industries, fruits are involve to de- aerated prior to pasteurization
process. There for retain natural fruit color.