The process of pasteurization was named after Louis Pasteur (1960S) who discovered that spoilage organisms could be inactivated in wine by applying heat at temperatures below its boiling point. The process was later applied to milk and remains the most important operation in the processing of milk.
Pasteurization made milk safer and the United State Food and drug Administration or FDA in the 1906-2006.
PASTEURISATION OF FOODS
Presented by Rekha
M.Sc. Third semester
The process of pasteurization was named after Louis Pasteur (1960S) who
discovered that spoilage organisms could be inactivated in wine by applying heat
at temperatures below its boiling point. The process was later applied to milk and
remains the most important operation in the processing of milk.
Pasteurization made milk safer and the United State Food and drug
Administration or FDA in the 1906-2006.
What is Pasteurization
Pasteurization involves heating food to a temperature that kills disease
causing microorganism and substantially reduces the levels of spoilage
Pasteurization is not intended to kill all micro-organisms in the food. Instead
pasteurization aims to reduce the number of viable pathogens so they are
unlikely to cause disease (assuming the pasteurized product is stored as
indicated and consumed before its expiration date).
Heat also destroy enzymes that make milk spoil, so pasteurized milk drinkable
for longer time.
Methods of pasteurization
Low temperature holding pasteurisation (LTH) Low Temperature
Long Time (LTLT), or Batch
High-temperature, short time (HTST) or continuous flow
Ultra heat treatment or ultrahigh temperature (UHT)
Low temperature holding pasteurisation (LTH) or Batch
The batch method uses a vat pasteurizer which consists of a jacketed vat surrounded by either
circulating water, steam or heating coils of water or steam. In the batch method, fluid milk is placed in
a vat pasteurizer, which consists of a vat surrounded by either circulating water, steam or heating coils
of water or steam. To cool the milk, either the milk is allowed to cool in the vat or the milk is removed
from the vat..
The batch or low-temp-long-time or holder pasteurization (LTLT) process is the traditional method of
In the vat the milk is heated to 62.8 C and held for 30 minutes followed by rapid cooling.
High-temperature, short time or continuous flow
In the continuous flow for high temperature, short time is flash-heating milk is forced between metal plates or
through pipes heated on the outside by hot water. While flowing under pressure, the milk is held at 72°C for
at least 15 seconds. Before being chilled back to 4°C or cooler, it flows through a heat exchanger to pre-
warm cold milk just entering the system. (HTST) pasteurized milk typically has a refrigerated shelf of two to
three weeks (HTST) cause less damage to the nutrient composition and sensory characteristics of foods than
do the low-temperature, long-time treatments.
This is better than the old way at preserving the nutrients and quality of foods.
This Pasteurizer is a plate pasteurizer for pasteurizing milk, juice, and egg products.
The Pasteurizer complies with European Safety Standard CE requirements, 3-A Sanitary Standards (No.11-
05), and is built according to PMO requirements.
HTST plate pasteurizer from 72°C (162°F) to 95°C (203°F) For 15 seconds.
Use: Milk pasteurization by fast heating, 80% regeneration and
precise heating to required temperature, delay, quick cooling by
regeneration and milk cooling section.
1. Balance tank to receive milk, with level control.
2 1-2 HP milk feed pump with stainless steel cover.
3. inline filter
4. flow gauge
5. micrometry flow
6. control valve
7. outlet temperature
8. control valve
9. 3-cell heat
10. exchanger for regeneration, heating and cooling
11. automatic flow alteration valve - air actuated, 20 sec. holding tube
(optional 2 min. further holding)
12. hot water system with circulation pump
13. electronic controller with thermostat for milk and water temperatures
14. electric operation board with electronic thermostats & illuminated control
15. Temperature recorder.
16. The pasteurizer is mounted on a stainless steel platform with wheels, and
equipped with milk hoses.
Capacities : 1100, 2200 Lbs/H
Electricity : 240/480V, 3 Phases, 60 Hz, 30Kw (1100Lb/H) 60Kw (2200Lb/H).
Air Pressure: 6 ATM.
Ultraheat treatment or ultrahigh temperature (UHT)
UHT is a continuous process and the product is packaged after sterilisation into
Typical temperatures and times specified for UHT treatment of milk are 130º C –
150º C for 1-3 seconds.
Sterilizes food by heating it above 130°C (275°F), the temperature required to kill
spores in milk, for 1 to 3 seconds. UHT is most commonly used in milk
production, but the process is also used for fruit juices, cream, soy milk, yogurt,
wine, soups, honey,
UHT milk has a typical shelf life of six to nine months, until opened.
Thereafter the milk is cooled to 7 C or lower.
The products have a better keeping quality and longer shelf life.
Liquid that have been treated in this way can stay unfrigerated for several months
if they packed right.
Main Features of UHT Sterilizer Pasteurizing Pasteurizer Tube in Tube Milk
It is equipped full-automatic control and touch screen.
Mainly used for aseptic filling and packing products
such as Tetra paper brick, Tetra paper pillow, aseptic
soft plastic pouch etc.
High heat efficiency, 90% of the heat can be reused
after the production process.
Temperature difference between the product and the
heating medium is small.
machine self sterilizing and whole procedures run
automatically, and all the procedures are recorded and
Control upon sterilizing temperature is precise and
reliable, and steam pressure and flow, product flow are
all automatically controlled.
The tubes internal surface is fine polished, tubes
layout enables automatic cleaning applicable.
OTHER PROCESSES USED TO PASTEURIZED FOODS
Ultra pasteurization - This involves the heating of milk and cream to at least 280° F (138°
C) for at least 2 seconds, but because of less stringent packaging, they must be refrigerated.
The shelf life of milk is extended 60 to 90 days. After opening, spoilage times for
ultrapasteurized products are similar to those of conventionally pasteurized products
Steam Pasteurization- This system used a chamber that exposes the beef to pressurized
steam for approximately 6 to 8 seconds. The steam raises the surface temperature of the
carcasses to 190° to 200° F (88° to 93°C). The carcasses are then cooled with a cold-water
spray, reducing pathogenic bacteria, such as E. coli O157:H7, Salmonella, and Listeria,
without the use of any chemicals. Steam pasteurization is used on nearly 50% of U.S. beef.
Irradiation Pasteurization - Foods, such as poultry, red meat, spices, and fruits and
vegetables, are subjected to small amounts of gamma rays. This process effectively controls
vegetative bacteria and parasitic foodborne pathogens and increases the storage time of
Different types of foods pasteurization
The yolk and whole-egg products are pasteurized in their raw form. The egg white is pasteurized in
its raw form if it is sold as a liquid or frozen product.
Dried Eggs - If eggs are sold dried, the egg white with the glucose removed is normally heat-treated
in the container by holding it for 7 days in a hot room at a minimum temperature of 130°F (54°C).
Whole Eggs Pasteurized in the Shell - Traditionally, eggs sold to customers in the shell have not
been pasteurized. Egg whites coagulate at 140°F (60°C). Therefore, heating an egg above 140°F
would cook the egg, so processors pasteurize the egg in the shell at a low temperature, 130°F
(54°C), for a long time, 45 minutes. Pasteurizing eggs reduces the risk of contamination from
pathogenic bacteria, such as Salmonella, which can cause severe illness and even death.
Milk - Pasteurization improves the quality of milk and milk products and gives them a longer shelf
life by destroying undesirable enzymes and spoilage bacteria. For example, the liquid is heated to
145°F (63°C) for at least 30 minutes or at least 161°F (72°C) for 15 seconds.
Today, many foods, such as eggs, milk, juices, spices and ice cream,are pasteurized.. The
temperatures and times are determined by what is necessary to destroy pathogenic bacteria and
other more heat-resistant disease-causing microorganisms that may be found in milk. The liquid is
then quickly cooled to 40°F (4°C). Other liquids, such as juices, are heat-processed in a similar
manner. Temperatures and times vary, depending on the product and the target organism.