The document discusses pasteurization, including its history and objectives. It describes different types of pasteurization processes like low-temperature long-time (LTLT), high-temperature short-time (HTST), ultra-high temperature (UHT), and vacuum pasteurization. LTLT heats milk to 63°C for 30 minutes while HTST heats it to 72°C for 15 seconds. UHT applies higher temperatures of 135-145°C for a few seconds. The document also discusses determining time-temperature parameters based on microbial destruction values and outlines the steps involved in various pasteurization methods. Moderate electric field pasteurization is mentioned as a new non-thermal alternative that uses electric

1. presentation
on
pasteurization
Submitted by-
Dr. Rishi Kumar
DEPARMENT OF VETERINARY PUBLIC HEALTH
COLLEGE OF VETERINARY SCIENCE & ANIMAL HUSBANDARY
DUVASU, MATHURA

2. Pasteurization  Pasteurization term coined after the
name of Louis Pasteur (1860-64)
 Demonstrated heating wine at a
temperature between 50-60C° killed
the spoilage organism and help in
preservation
 Application of this pasteurization
technique on milk was first time
attributed to Dr. Soxhlet of Germany
in 1886
 Pasteurization of meat done at 63C° -
73 C° but in meat canning
((commercial sterilization )is prefer
over pasteurization to avoid
nutritional loss.

3. Definition
 Process of heating every particle of milk to at least
63 C° for 30 minutes. Or 72 C° for 15 sec. or any
time- temperature combination which equally
efficient in approved and properly operated
equipped and finally cooling to 4 C°
 International dairy federation ( IDF) pasteurization
defined as process applied to a products with an
object of minimizing possible heath hazards arising
from pathogenic micro organism associated with
milk by heat treatment, which is consistent with
minimal chemical, physical and organoleptic
changes in the products

4. Objectives
 1. Public Health Aspect- Milk safe
for human consumption by
destruction of cent percent pathogenic
microorganism.
 2. Keeping Quality Aspect -Improve
keeping qualities of milk by
destruction of almost all spoilage
organisms ( up to 85 to 99 percent ).

5. Objections
 Reduce the cream line of milk
 Fails to destroy bacterial toxin in milk.
 Diminishes significantly the nutritive value of milk.
 Cause 10 % loss of thiamin and 20 % loss ascorbic acid.

6. Formulation of standards
1. Complete destruction of pathogens( 62.5 C°)
2. Negative phosphate test ( 61.1 C°)
3. cream line reduction ( 63.2 C°)
Index organism for pasteurization – earlier mycobacterium
tuberculosis being consider as the most heat resistance among
pathogens but now it is Q fever organism Coxiella Bernette was
considered as most heat resistant.

7. How we decide time & temperature for
pasteurization
 D value:- Measures the time required to kill 90% of the population of a
particular microorganism in a specific medium at a specific temperature
 Z-value:- Is defined as the temperature coefficient of microbial
destruction, i.e. as the number of degrees of temperature which causes a
10-fold variation of D
 F-value: – The number of minutes required to kill a known population of
microorganisms in a given food at 121C°

8. Types of pasteurization
1.Low temperature long time / Batch
pasteurization ( LTLT)
1.Water jacketed vat or flooded tank system
2.Water spray type
3.Coil vat type
4.High velocity liquid type
2.High temperature short time
pasteurization ( HTST)
3.Ultra – high temperature
pasteurization (UHT)
1.Direct heating system
2.In- direct heating system
4.Vacuums pasteurization
5.Stassanization

9. Low temperature
long time ( LTLT)/
Batch pasteurization
 The milk is heated to 63C°/145 ℉ for
30 minutes and promptly cooled to
5C°
 In this method heating and cooling of
the product is done through a metal
wall.
 LTLT pasteurization is preferred in
ice-cream industries.
 Depending upon the method of
heating the batch process/LTLT may
be classified into four type

10. 1.Water jacketed vat or flooded tank system
 Double walled around the sides and bottom in which hot water or
steam under partial vacuum circulates for heating and cold water for
cooling.
 Multipurpose or multi process vat

11. 2.Water spray type
 Consist of inner tank for product surrounded by an outer tank to
form space between two.
 Hot water is sprayed from a perforated pipe over the outer surface of
then tank holding product.
 Temperature of hot water kept 72 C° To heat the product to 62 C°.

12. 3.Coil vat type
 Heating or cooling medium is pumped through a coil placed
either horizontal / vertical. Coil is turn around products.
 Turning coil speed of about 130 rpm agitates the products.

13. 4.High velocity liquid type
 Heating and cooling media is pumped at a high velocity over the
outside surface of the tank through pipes surrounding the tank.
 Suitable for small plants and low value products

14. High temperature short time
(HTST)pasteurization
 The HTST system usually employs plate heat exchanger for heating,
regeneration and cooling
 Milk is heated to 72 C° for 15 seconds.
 Pressure system in system-
Pasteurized milk -15 psi
Raw milk- 14 psi
Heating / cooling medium – 12 to 13 psi
Heating media is hot water and cooling media is water + acetone in 50 – 50 %
ratio .

17. Ultra high temperature
 UHT pasteurization was developed in 1950
 Objective – to reduce nutritional loss caused by in-container
sterilization
 Uses – for tetra packed milk
 Milk is heated to 135 C° -145 C° for few seconds

18. UHT types
Indirect heating system Direct heating system
1.Heat is transmitted to the milk
through a stainless steel wall
2. Heat exchanger may be of plate
type, tubular type , tubular coil
type
Heating medium in steam under
pressure
1.Milk is heated by direct contact
with heat
2. Accompanied either by injecting
steam into products or admitting
the products into chamber
containing an atm. Of high
pressure

19. UHT STEPS- DIRECT HEATING
Storage tank
Flow control balance tank
Preheating up to 80C°
Steam injected in to liquid
Instantaneous heating to the desire temp.
from 180C° to 145 C° in 0.1 sec.

20. After maintain liquid at the desire temperature
for few seconds ,it discharge into vessel at
reduce pressure.
Almost Instantaneous evaporation of water
occur causing rapid cooling.
Water evaporates should equal to amount of
steam absorbed.

21. Indirect Heating system steps
Storage tank
Flow control balance tank
Heat exchanger
Heating section – milk is heated to 85 C° and then
homogenized
Milk is hold 5 to 7 min in a holder tank

22. 2nd Generation heating-milk is heated by
steam in heating section
Now milk temp -135 C° - 145 C°
FDV – temp 70 C°
Pasteurization Milk filling
FDV – temp 70 C°
Unpasteurized milk return in to FCBT
Pasteurization Milk filling in bottle

24.  Uperization :- Short form of UHT , In which milk is heated with
direct steam up to 150 C° for fraction of seconds
 Vacreation :- Also known as vacuum pasteurization ,pasteurized
cream under reduced pressure by direct steam. It is designed to
remove feed and other volatile flavors from cream and to
pasteurized it for butter manufacturer
 Stassanization :- Milk is heated to 74 C° for seven sec, is carried
out in tabular heat exchanger consisting of three concentric tubes

25. Moderate electric field pasteurization of milk
 A new non-thermal moderate electric field
(MEF) process for milk pasteurization To
evaluate the applicability of this process, fresh
milk was treated by MEF at electrical field
strength (EFS) of 8.33, 14.58, and 20.80 V/cm
 Moderate electric field (MEF) consumed 63%
lower energy than conventional thermal
pasteurization.
 MEF inactivated alkaline phosphatase by 100%.
 MEF reduced S. aureus from
2.16 × 104 CFU/mL to non-detectable level at
temperatures below 22 °C.
 Decontamination enhanced by 55% at the
highest field strength (EFS) and the minimum
mass flow rate (MFR).
 The longest shelf-life at 5 °C was 15 days that
was achieved when EFS and MFR were
20 V/cm and 0.018 kg/s, respectively