thousands of years milk is being consumed by people of all communities. Milk
can be obtained from cows, buffaloes, water buffaloes, goats, sheep, horses,
camels, yak, donkeys or even reindeer. Unheated or unprocessed milk was being
used for quite a long time and was considered safe and reliable. It was very
important for different cultures in tropics even centuries before the invention
of refrigeration. Primitive people use fermentation to preserve and take
benefit from it that made it even better food for them.
is fresh, clean, secretion of lacteal glands of healthy milking animals (one or
more) excluding milk obtained 15 days before and 5 days after calving and which
should contain the prescribed standards of Fat and SNF.
Components % age
the milk obtained from milk animals is processed later but we cannot call it
fabricated or engineered food. It has about 87% water and remaining 13% are
solids. Solids include fat, proteins, carbohydrates, vitamins and minerals. Fat
has fat soluble while water has water soluble vitamins in it. Presence of all
these nutrients in milk make it nearly perfect natural food.
production in Pakistan is mostly done in villages by farmers with small land
holdings or by agricultural laborers that are landless. A large amount of milk
being produced is collected by suppliers and dairies but still people convert
it into traditional dairy products due to lack of facilities like storage,
refrigeration and transportation. Due to economic and educational backwardness
of producer, milk is produced under most unsatisfactory conditions.
animals are usually kept in a part of living space, small closed or open yards
near to house with flooring of mud. In summer buffaloes wallow in ponds making
themselves full of dirt and rarely washed before milking.
milking is adopted after suckling by calf is being done. Only few large modern
farms use milking machines for this purpose. Due to unavailability of
refrigeration and long distance between producer and consumer milk is held at
ambient temperatures for long time that leads to high microbial growth.
Exposure to high ambient temperature for long time in this region is the main
cause of rapid microbial growth in milk. 
has 87-88% water which is freely available for microbes and other chemical reactions.
Also, milk has fat, carbohydrates, protein and favorable pH that fulfill all
the requirements of microbes. So, it is very favorable food for microorganisms.
Microbes will spoil it in 6-8 hours if not handled properly after milking. Most
commonly bacteria are present in milk, while some species of yeast and mold are
also present in it. Most commonly present microbes in raw milk are as under:
genera finds its way to milk through soil and water. This genus is responsible
for spoilage in milk e.g. blue color is produced by Pseudomonas synciani,
yellow color is produced by Pseudomonas synxantha, brown color is produced by
Pseudomonas putrificians, green color is produced by Pseudomonas aurogenosa.
They also induce flavor to milk e.g. Pseudomonas mucidolense produces potato
like flavor in the milk. Pseudomonas
fluorescenscan cause lipolysis and proteolysis in milk. Pseudomonas fragi can produce
extracellular enzymes (proteolytic and lipolytic) that are heat stable and
cause spoilage.This causes bitty (broken) cream & milk due to formation of
flakes or small clots in milk & cream due to lecithinase and phospholipases
activity. Major cause of this spoilage is phospholipases.Adapting common
GMP’scan reduce their incidence and can easily be killed by pasteurization.,
Brucella spp is found in many animals
including cattle, sheep, and goats. Fever, headaches, backpain, sweats and
physical weakness are symptoms of its illness. Sometimes fever, fatigue and
joint pain may occur. Only way to control
is through pasteurization.
jejuni is found
in contaminated water sources and in the intestinal tract excreting in feces of
cattle and on udder due to unhygienic conditions. Disease like fever, abdominal pain, cramping, diarrhea, bloody diarrhea,
nausea and vomiting are caused due to its presence. It can be reduced by
following GMP’s and by pasteurization.
Coxiellaburnetii is found in many animals and
shed in milk, urine and feces of animals. It causes Q fever whose symptoms
include sudden onset of high fever, chills, severe headache, sweats,chest pain,
abdominal pain, nausea, vomiting, diarrhea, sore throat and cough that may lead
to death if not treated.Conditions for
milk pasteurization are specifically established to destroy it due its heat
resistant non-spore forming nature. Apart from pasteurization it can be
reduced by maintaining hygienic conditions.
Escherichia coli O157:H7 is one strain from a
large bacterial family. E. coli strains
are considered fecal coliforms. Its toxins can cause illness in humans e.g.
bloody diarrhea and abdominal cramps. In some cases, i.e. in young children it
causes hemolytic uremic syndrome that destroys red blood cells and cause kidney
damage or failure and in some cases death. It is also involved in spoilageof
milk. It causes gas production in milk due to acidic fermentation of lactose
also called as “Stormy Fermentation” because of foam formation on surface. Such
milk is not fit for human consumption. It also causes sweet curdling of milk
due to enzyme “proteases” which targets casein bacteria use lactose and convert
into acid and aldehyde components that causes sweetness.Following hygienic
conditions can greatly decrease it and is destroyed by pasteurization.
aureus is present due to mastitis in milking animals. This bacteriumcauses skin
infections, respiratory disease and food poisoning. It can be controlled by
improving animal health, good quality feed and pasteurization that readily
agalactiae is present in feces, contaminated water and present in milking
animals suffering from mastitis.It causes infections in new born that starts
from fever, vomiting and irritability, and can consequently lead to hearing
loss. It can be controlled by improving animal health, good quality feed and by
thermophiles is also present in animals suffering from mastitis. This microbe
causes spoilage in milk and is not involved in any diseases and acts as
probiotic. It can be controlled by improving animal health, good quality feed
and by pasteurization.
lactis is also present in milk of animals suffering from mastitis. This microbe
causes acid fermentation resulting in sour acidic flavor and it act as
probiotic in human body. It is easily killed during pasteurization.
animals suffering from mastitis also contain Streptococcus cremoris in their
milk. It causes Streptococcal infections e.g. fever, sour throat, tonsillitis
and some pneumonias. It can be reduced by improving animal health, good quality
feed and by pasteurization.
generally comes from environment as it is present in air and often grows on
feed and dung of animals. This microbe causes spoilage of milk i.e. doing
heterofermentation by converting sugars present in milk into different products
thus it causes a wide range of spoilage activity. It is also responsible in
acid and slime production in milk. It can be controlled by maintaining hygiene
and can easily be destroyed by pasteurization.
cereus is naturally found in cattle gut. Feed act as major source. It can enter
the milk due to unhygienic environment.
It causes a minority of illnesses (2–5%) e.g. severe nausea,
It causes sweet curdling of milk due to enzyme “proteases” which targets
casein, use lactose and convert into acids and aldehyde components that causes
sweetness. It is involved in gas production by converting lactose into acids
and CO2 on fermentation which is also called “Stormy Fermentation”
due to foam on surface. Such milk is not fit for human consumption. It is also
involved in proteolysis which causes butyrine smell. It causes bitty (broken)
cream & milk due to formation of flakes or small clots in milk & cream
due to lecithinase and phospholipases activity. It can be controlled by
maintaining hygienic environment and by pasteurization. It is spore forming so
proper pasteurization is needed to destroy its spores. ,, 
lactis is present in animals suffering from mastitis. This microbe causes
spoilage in milk doesn’t cause any disease and act as probiotic. It is easily
killed by pasteurization.
bulgaricus is naturally present in intestine of animals and humans so major
source is through animal contact, dirty udders and utensils. It is not
responsible for any type of disease but it is involved in acid fermentation
which causes milk spoilage. It is easily killed during pasteurization.Lactobacillus
acidophilus is naturally present in human and animal gastrointestinal tract and
mouth. This specie ferments sugars into lactic acid. It doesn’t cause any
disease and some strains act as probiotic. It can easily be killed by
pasteurization or any other such heat treatment.
genera is primarily facultative parasite and commensal of humans and other
animals by living in and around their sweat glands, sebaceous glands and other
areas of their skin thus finds its way in milk due to unhygienic conditions. It
causes some skin diseases in humans when infected milk gets contact with skin
and causes skin problems that resembles acne. 
Listeria monocytogenes is found in water and soil so
enters milk from many environmental sources. It causes listeriosis i.e.
headache, fever, muscle aches, stiff neck, septicemia, meningitis and in worse
cases cause miscarriage, stillbirth, premature delivery, abortion, or death.
Maintaining hygienic environment can reduce their presence and can be destroyed
by pasteurization. 
Mycobacterium bovis and Mycobacterium tuberculosis are present in infected cattle
worldwide. They cause lung disease tuberculosis. They can only be controlled
Salmonella spp. is present in the intestinal
tracts of almost all warm-blooded animals thus unhygienic conditions during milking
are major cause of this. It causes illness whose symptoms include diarrhea,
abdominal cramps, and fever. It is responsible for gas production due to
fermentation of lactose into acids and CO2also termed as “Stormy
Fermentation”. Such milk is not fit for human consumption. Its number can be
reduced by maintaining hygienic environment and by pasteurization. , 
Yersinia enterocolitica is found in farm animal’s
intestinal tract and in the environment. It causes illness i.e. fever,
abdominal pain and diarrhea. It can be controlled by hygienic environment and
by pasteurization. 
butyricum is present in soil so flooring or bedding is a major source of it. It
doesn’t cause any disease but cause spoilage in milk due to production of butyric
acid by fermentation. It also causes gas production in milk by acidic
fermentation of lactose which causes foaming and termed as “Stormy
Fermentation”. Such milk is not fit for human consumption. They are also
responsible for proteolysis mostly alkaline proteolysis in milk which results
in butyrine smell and produces sharp sour flavor in milk. It causes bitty (broken)
cream & milk due to formation of flakes or small clots in milk & cream
due to lecithinase and phospholipases activity. It is comparatively tough to
kill on pasteurization temperature and mostly survives pasteurization so good
hygiene and good bedding can reduce this microbe. , , 
aerogenes is mostly found in gastrointestinal tract of animal where it does not
cause any disease. It is also found on various feed materials, soil and wastes.
So, find its way in milk due unhygienic environment. It causes bacteremia,
ophthalmic infections, intra-abdominal infections, skin and soft-tissue
infections, lower respiratory tract infections, CNS infections, urinary tract
infections (UTIs), endocarditis, septic arthritis and osteomyelitis. It also
causes gas production due to acidic fermentation of lactose which causes
foaming and termed as “Stormy Fermentation”. Such milk is not fit for human
consumption. It causes bitty (broken) cream & milk due to formation of
flakes or small clots in milk & cream due to activity of lecithinase and
phospholipases. Ropy fermentation
is also caused by this i.e. abnormal ropiness and viscous-slimy textured milk.
is a yeast. It grows on feed, bedding material and on cow dung. Its spores are
also present in air thus unhygienic environment is responsible for their
transfer to milk. They are lactose positive hence cause lactose fermentation leading
to gas production causing foaming on surface and termed as “Stormy
Fermentation”. Such milk is not fit for human consumption. It also results in
changed milk flavor shifting it towards slightly sour taste. , 
is a mold. It grows on feed especially bread that is given to animals in
villages, bedding material and on cow dung. Its spores are present in air and
unhygienic environment leads it to milk. They cause acidic fermentation of
lactose in milk that leads to gas production this causes foaming on surface and
called as “Stormy Fermentation”. It causes proteolysis in milk, proteases
target casein and convert it into acids and aldehyde components resulting in
sweet taste. They produce Aflatoxins that can cause serious health hazards e.g.
renal failure, liver damage, nervous breakdown, and problems related to
digestion. In rare cases can cause death of individual. , 
is also a mold. It grows on feed especially bread that is given to animals in
villages, bedding material and on cow dung. Its spores are present in air that
lead them to milk. They cause gas production by acidic fermentation of lactose
which results in foaming on surface and hence called as “Stormy Fermentation”.
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08-Feb-2014. Milk production and procurement in Pakistan.Agrihunt.pk.
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1250 H Street, NW, Suite 900 Washington, DC 20005
5. Dr. ali al-Shammary.
26-Aug-2014. Biochemical changes
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