What is
pasteurization ? History and Process of Pasteurization > What
is raw milk? Is it true that raw milk
has more enzymes and nutrients than pasteurized milk? With Some Other Information of Raw
& Pasteurized milk And milk
products ?
Pasteurization According
To International Dairy Foods
Association
Pasteurization
Pasteurization is a process, named after
scientist Louis Pasteur, that applies heat to destroy pathogens in foods. For
the dairy industry, the terms "pasteurization,"
"pasteurized" and similar terms mean the process of heating every
particle of milk or milk product, in properly designed and operated equipment,
to one of the temperatures given in the following chart and held continuously
at or above that temperature for at least the corresponding specified time:
|
*If
the fat content of the milk product is 10percent or more, or if it contains
added sweeteners, or if it is concentrated (condensed), the specified
temperature shall be increased by 3ºC (5ºF). Eggnog shall be heated to at least
the following temperature and time specifications:
|
The
original method of pasteurization was vat pasteurization, which heats milk or
other liquid ingredients in a large tank for at least 30 minutes. It is now
used primarily in the dairy industry for preparing milk for making starter
cultures in the processing of cheese, yogurt, buttermilk and for pasteurizing
some ice cream mixes.
The
most common method of pasteurization in the United States
Another
method, aseptic processing, which is also known as Ultra High Temperature
(UHT), involves heating the milk using commercially sterile equipment and
filling it under aseptic conditions into hermetically sealed packaging. The
product is termed "shelf stable" and does not need refrigeration
until opened. All aseptic operations are required to file their processes with
the Food and Drug Administration's "Process Authority." There is no
set time or temperature for aseptic processing; the Process Authority
establishes and validates the proper time and temperature based on the equipment
used and the products being processed.
Information of Pasteurization
From
Wikipedia, the free
encyclopedia
Pasteurization (American English)
or pasteurisation (British English) is a process
invented by French scientist Louis Pasteur during the nineteenth century. In 1864
Pasteur discovered that heating beer and wine was enough to kill most of the
bacteria that caused spoilage, preventing these beverages from turning sour.
This was achieved by eliminating pathogenic microbes and lowering microbial
numbers to prolong the quality of the beverage. Today the process of
pasteurization is used widely in the dairy and foodindustries for microbial control and
preservation of the food consumed.
Unlike sterilization, pasteurization is not intended
to kill all micro-organisms in the food. Instead, it aims to
reduce the number of viable pathogens so they are unlikely to cause disease
(assuming the pasteurized product is stored as indicated and is consumed before
its expiration date). Commercial-scale sterilization of food is not common
because it adversely affects the taste and quality of the product. Certain
foods, such as dairy products, may be superheated to ensure pathogenic microbes
are destroyed..
History of Pasteurization ;
Louis Pasteur’s pasteurization
experiment illustrates the fact that the spoilage of liquid was caused by
particles in the air rather than the air itself. These experiments were
important pieces of evidence supporting the idea of Germ Theory of Disease.
Before the widespread urban growth caused by industrialization, people
kept dairy cows even in urban areas and the short time period between
production and consumption minimised the disease risk of drinking raw milk.[19] However, as urban densities increased and supply chains lengthened
to the distance from country to city, raw milk (often days old) began to be
recognised as a source of disease. For example, between 1912 and 1937 some
65,000 people died of tuberculosis contracted from consuming milk in England Wales
Developed countries adopted milk pasteurization to prevent such disease
and loss of life, and as a result milk is now widely considered one of the safest
foods.[]
A traditional form of
pasteurization by scalding and straining of cream to increase the keeping
qualities of butter was practiced in England before 1773 and was introduced to Boston in the USA by 1773, although it was not widely practiced
in the United States
Process of pasteurization ;
Older pasteurization methods used temperatures below boiling, since at
very high temperatures, micelles of the milk protein casein will irreversibly aggregate, or "curdle". Newer
methods use higher temperature, but shorten the time. Among the pasteurization
methods listed below, the two main types of pasteurization used today are high-temperature, short-time (HTST, also known as
"flash") and extended shelf life (ESL):
·
HTST milk is
forced between metal plates or through pipes heated on the outside by hot
water, and the milk is heated to 72 °C (161 °F) for 15 seconds. Milk simply labeled "pasteurized" is usually treated with
the HTST method.
·
UHT,
also known as ultra-heat-treating, processing holds the milk at a temperature
of 140 °C (284 °F) for four seconds. During UHT processing milk is
sterilized and not pasteurized. This process allows milk or juice to be stored
several months without refrigeration. The process is achieved by spraying the
milk or juice through a nozzle into a chamber that is filled with
high-temperature steam under pressure. After the temperature reaches
140 °C the fluid is cooled instantly in a vacuum chamber, and packed in a
presterilized airtight container.[28] Milk labeled "ultra-pasteurized" or simply
"UHT" has been treated with the UHT method.
·
ESL
milk has a microbial filtration step and lower temperatures than UHT milk.[29] Since 2007, it is no longer a legal requirement in European
countries (for example in Germany) to declare ESL milk as ultra-heated;
consequently, it is now often labeled as "fresh milk" and just
advertised as having an "extended shelf life", making it increasingly
difficult to distinguish ESL milk from traditionally pasteurized fresh milk.
·
A less
conventional, but US FDA-legal, alternative (typically for home pasteurization)
is to heat milk at 63 °C (145 °F) for 30 minutes.
Pasteurization methods are usually standardized and controlled by
national food safety agencies (such as the USDA in the United
States and the Food Standards Agency in theUnited
Kingdom). These agencies require that milk be HTST pasteurized to qualify
for the pasteurized label. Dairy product standards differ, depending on fat
content and intended usage. For example, pasteurization standards for cream differ from standards for fluid milk,
and standards for pasteurizing cheese are designed to preserve the enzymephosphatase,
which aids cutting. In Canada, all milk produced at a processor and intended
for consumption must be pasteurized, which legally requires that it be heated
to at least 72 °C for at least 16 seconds,[31] then cooling it to 4 °C to ensure any harmful bacteria are
destroyed. The UK
A process similar to pasteurization is thermization,
which uses lower temperatures to kill bacteria in milk. It allows a milk
product, such as cheese, to retain more of the original taste, but thermized
foods are not considered pasteurized by food regulators.[30]
Microwave volumetric heating ;
Microwave volumetric heating (MVH) is the newest available
pasteurization technology. It uses microwaves to heat liquids, suspensions, or
semi-solids in a continuous flow. Because MVH delivers energy evenly and deeply
into the whole body of a flowing product, it allows for gentler and shorter
heating, so that almost all heat-sensitive substances in the milk are
preserved.]
Efficiency of Pasteurization ;
The HTST pasteurization standard was designed to achieve a five-log
reduction, killing 99.999% of the number of viable micro-organisms in milk.[34] This is considered adequate for destroying almost all yeasts, molds, and common spoilage bacteria and also to ensure adequate
destruction of common pathogenic, heat-resistant organisms (includingMycobacterium tuberculosis, which
causes tuberculosis,
but not Coxiella
burnetii, which causes Q fever).[34] As a precaution, modern equipment tests and identifies bacteria in
milk being processed. HTST pasteurization processes must be designed so the
milk is heated evenly, and no part of the milk is subject to a shorter time or
a lower temperature.
Even pasteurization without quality control can be effective, though
this is generally not permitted for human consumption; a study of farms feeding
calves on pasteurized waste milk using a mixture of pasteurization technologies
(none of which were routinely monitored for performance) found the resulting
pasteurized milk to meet safety requirements at least 92% of the time.
An effect of the heating of pasteurization is that some vitamin,
mineral, and beneficial (or probiotic)
bacteria is lost. Soluble calcium and phosphorus levels decrease by 5%,
thiamine (vitamin B1) and vitamin B12 (cobalamin) levels by
10%, and vitamin C levels by 20%.[20][36] However, these losses are not significant nutritionally
Verification of Pasteurization ;
Direct microbiological techniques are the ultimate measurement of
pathogen contamination but these are costly and time consuming (24–48 hours),
which means that products are able to spoil by the time pasteurization is
verified.
As
a result of the unsuitability of microbiological techniques, milk
pasteurization efficacy is typically monitored by checking for the presence of alkaline phosphatase, which is denatured by
pasteurization. B.
tuberculosis, the bacterium requiring the highest temperature to be killed
of all milk pathogens is killed at similar ranges of temperature and time as
those which denature alkaline phosphatase. For this reason, presence of
alkaline phosphatase is deemed to be an ideal diagnostic tool for
pasteurization efficacy.
Phosphatase denaturing was
originally monitored using a phenol-phosphate
substrate. When hydrolysed by the enzyme these compounds liberate phenols,
which were then reacted with dibromoquinonechlorimide to give a colour change, which itself
was measured by checking absorption at 610 nm (spectrophotometry).
Some of the phenols used were inherently coloured (phenolpthalein, nitrophenol)
and were simply assayed unreacted.[32] Spectrophotometric analysis is satisfactory but is of relatively
low accuracy because many natural products are coloured. For this reason,
modern systems (since 1990) use fluorometry which is able to detect much lower
levels of raw milk contamination.
Milk and milk products provide
a wealth of nutrition benefits. But raw milk can harbor dangerous
microorganisms that can pose serious health risks to you and your family.
According to an analysis by the Centers for Disease Control and Prevention
(CDC), between 1993 and 2006 more than 1500 people in the United States
Raw milk is milk from cows,
sheep, or goats that has not been pasteurized to kill harmful bacteria. This
raw, unpasteurized milk can carry dangerous bacteria such as Salmonella, E. coli, and Listeria, which are responsible for
causing numerous foodborne illnesses.
These harmful bacteria can
seriously affect the health of anyone who drinks raw milk, or eats foods made
from raw milk. However, the bacteria in raw milk can be especially dangerous to people with weakened immune systems, older
adults, pregnant women, and children. In fact, the CDC analysis
found that foodborne illness from raw milk especially affected children and
teenagers.
"Pasteurized Milk"
Some Explaination ;
Pasteurization is a process
that kills harmful bacteria by heating milk to a specific temperature for a set
period of time. First developed by Louis Pasteur in 1864, pasteurization kills
harmful organisms responsible for such diseases as listeriosis, typhoid fever,
tuberculosis, diphtheria, and brucellosis.
Research shows no meaningful
difference in the nutritional values of pasteurized and unpasteurized milk.
Pasteurized milk contains low levels of the type of nonpathogenic bacteria that
can cause food spoilage, so storing your pasteurized milk in the refrigerator
is still important.
Raw Milk &
Pasteurization: Debunking Milk Myths
While pasteurization has helped
provide safe, nutrient-rich milk and cheese for over 120 years, some people
continue to believe that pasteurization harms milk and that raw milk is a safe
healthier alternative.
Here are some common myths and
proven facts about milk and pasteurization:
·
Pasteurizing milk DOES NOT cause lactose intolerance and allergic
reactions. Both raw milk and pasteurized milk can cause allergic reactions in
people sensitive to milk proteins.
·
Raw milk DOES NOT kill dangerous pathogens by itself.
·
Pasteurization DOES NOT reduce milk's nutritional value.
·
Pasteurization DOES NOT mean that it is safe to leave milk out
of the refrigerator for extended time, particularly after it has been opened.
·
Pasteurization DOES kill harmful bacteria.
·
Pasteurization DOES save lives.
Raw Milk may
causes some Serious Illness ;
Symptoms and
Advice ;
Symptoms of foodborne
illness include:
·
Vomiting, diarrhea, and
abdominal pain
·
Flulike symptoms
such as fever, headache, and body ache
While most
healthy people will recover from an illness caused by harmful bacteria in raw
milk - or in foods made with raw milk - within a short period of time, some can
develop symptoms that are chronic, severe, or even life-threatening.
If you or someone you know
becomes ill after consuming raw milk or products made from raw milk - or, if
you are pregnant and think you could have consumed contaminated raw milk or
cheese - see a doctor or healthcare provider immediately.
What is raw milk?
Raw milk is milk from cows, goats, sheep, or other animals that has not
been pasteurized. Although precise data are not available, it is thought that
less than 1% of milk sold to consumers in the United States
What are the risks associated with
drinking of raw milk?
Raw milk can carry harmful bacteria and other germs that can make you
very sick or kill you. While it is possible to get foodborne illnesses from
many different foods, raw milk is one of the riskiest of all.
Getting sick from raw milk can mean many days of diarrhea, stomach
cramping, and vomiting. Less commonly, it can mean kidney failure, paralysis,
chronic disorders, and even death.
Many people who chose raw milk thinking they would improve their health
instead found themselves (or their loved ones) sick in a hospital for several
weeks fighting for their lives from infections caused by germs in raw milk. For
example, a person can develop severe or even life-threatening diseases, such as
Guillain-Barré syndrome, which can cause paralysis, and hemolytic uremic
syndrome, which can result in kidney failure and stroke.
·
Illness can occur from the
same brand and source of raw milk that people had been drinking for a long time
without becoming ill.
·
A wide variety of germs
that are sometimes found in raw milk, can make people sick, including bacteria (e.g., Brucella, Campylobacter, Listeria,Mycobacterium bovis (a cause of tuberculosis),Salmonella,
Shiga toxin-producing Escherichia coli [e.g., E. coli O157], Shigella, Yersinia), parasites (e.g.,Giardia),
and viruses (e.g., norovirus).
·
Each ill person’s symptoms can differ, depending on the type of
germ, the amount of contamination, and the person’s immune defenses.
Who is at greatest risk of getting
sick from drinking raw milk?
The risk of getting sick from drinking raw milk is greater for infants
and young children, the elderly, pregnant women, and people with weakened
immune systems, such as people with cancer, an organ transplant, or HIV/AIDS,
than it is for healthy school-aged children and adults. But, it is important to
remember that healthy people of any age can get very sick or even die if they
drink raw milk contaminated with harmful germs.
Can drinking raw milk hurt me or
my family?
Yes. Raw milk can cause serious
infections. Raw milk and raw milk products (such as cheeses and yogurts made
with raw milk) can be contaminated with bacteria that can cause serious
illness, hospitalization, or death. These harmful bacteria include Brucella, Campylobacter, Listeria, Mycobacterium
bovis,Salmonella,
Shiga toxin-producing E. coli, Shigella, Streptococcus
pyogenes, and Yersinia enterocolitica. From 1998
through 2011, 148 outbreaks due to consumption of raw milk or raw milk products
were reported to CDC. These resulted in 2,384 illnesses, 284 hospitalizations,
and 2 deaths. Most of these illnesses were caused by Escherichia
coli, Campylobacter, Salmonella,
or Listeria. It is important to note that a substantial proportion
of the raw milk-associated disease burden falls on children; among the 104
outbreaks from 1998-2011 with information on the patients’ ages available, 82%
involved at least one person younger than 20 years old.
Because not all cases of foodborne illness
are recognized and reported, the actual number of illnesses associated with raw
milk likely is greater.
Aren't raw or natural foods better
than processed foods?
Many people believe that foods with no or
minimal processing are better for their health. Many people also believe that
small, local farms are better sources of healthy food. However, some types of
processing are needed to protect health. For example, consumers process raw meat,
poultry, and fish for safety by cooking. Similarly, when milk is pasteurized,
it is heated just long enough to kill disease-causing germs. Most nutrients
remain after milk is pasteurized. There are many local, small farms that offer
pasteurized organic milk and cheese products.
Does drinking raw milk prevent
or cure any diseases, such as asthma, allergies, heart disease, or cancer?
No. There are no health benefits from drinking raw milk that cannot be
obtained from drinking pasteurized milk that is free of disease-causing
bacteria. The process of pasteurization of milk has never been found to be the
cause of chronic diseases, allergies, or developmental or behavioral problems.
I know people who have been
drinking raw milk for years, and they never got sick. Why is that?
The presence of germs in raw
milk is unpredictable. The number of disease-causing germs in the raw milk may
be too low to make a person sick for a long time, and later high enough to make
the same person seriously ill. For some people, drinking contaminated raw milk
just once could make them really sick. Even if you trust the farmer and your
store, raw milk is never a guaranteed safe product. Drinking raw milk means
taking a real risk of getting very sick.
More information
What is pasteurization, and how does
it work in milk?
Pasteurization is the process of heating milk
to a high enough temperature for a long enough time to kill illness-causing
bacteria contained in the milk. As most commonly applied, pasteurization heats
milk to a high temperature for a short time, which kills the bacteria that
cause illness. It was invented in a time when millions of people became sick
and died of diseases like tuberculosis, scarlet fever, typhoid fever, and other
infections that were transmitted through raw milk. Pasteurization has prevented
millions of people from becoming ill.
Raw milk contains bacteria, and some of them
can be harmful. So, if you’re thinking about consuming raw milk because you
believe that it is a good source of beneficial bacteria, you need to know that
it isn’t and you may instead get sick from the harmful bacteria. If you think
that certain types of bacteria may be beneficial to your health consider
getting them from foods that don’t involve such a high risk. For example,
so-called probiotic bacteria are sometimes added to pasteurized fermented
foods, such as yogurt and kefir.
Pasteurized milk products have occasionally
caused illnesses and outbreaks. Usually, this has happened because of germs
introduced in the dairy after the pasteurization process. Pasteurized milk that
is correctly handled in the dairy, bottled, sealed, and refrigerated after
pasteurization, and that is properly handled by the consumer, is very unlikely
to contain illness-causing bacteria. Considering the amount of pasteurized milk
consumed in the United States
What is the history of the
recommendation for pasteurization in the United
States
Routine pasteurization of milk began in the United States
Many medical and scientific
organizations recommend pasteurization for all milk consumed by humans; these
include CDC, the Food and Drug Administration, the American Academy
Does pasteurization change milk’s
nutritional benefits?
No. Many studies have shown that
pasteurization does not significantly change the nutritional value of milk and
dairy products. All of the nutritional benefits of drinking milk are available
from pasteurized milk without the risk of disease that comes with drinking raw
milk.
Is it true that raw milk has more
enzymes and nutrients than pasteurized milk?
While it’s true that the heating process of pasteurization does
inactivate some enzymes in milk, the enzymes in raw animal milk are not thought
to be important in human health. Some nutrients are somewhat reduced in
pasteurized milk, but the United States
( Source ; from internate )
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