Preheating refers
to heating milk before operation.
The milk is
preheated for efficient filtration and clarification.
As the
temperature of the milk increases, the viscosity of milk decreases and
more efficient filtration/clarification result.
The usual
temp of preheating --------35-40
Equipment
used for preheating--------Plate or Tubular heater.
To improve
aesthetic quality of milk by removing visible foreign matter.
Two types
of filters--------------1. cold filter 2. warm filter.
Milk is
received in plant; it is chilled to 5 or below and stored cool till used.
Internal
tubular cooler consists of stainless-steel tube about 2.5-5.0 cm. in
diameter.
Cooling
efficiency of internal tubular cooler is lower than plate cooler.
Insulator
or refrigerated storage tanks-----5-7.5 cm of insulating material bent
inner and outer lining; the space bent two lining is used for circulation of
the cooling medium.
The term
pasteurization has been coined after name of Louis Pasteur of France.
Pasteurization
of milk first attributed to Dr. Soxhelt of Germany in 1886.
In
Pasteurization destruction of 85-99% of spoilage organism.
Pasteurized milk
will not clot with rennet.
Emerging Index
organism for Pasteurization---------Listeria Monocytogens, Coxiella Brunetti
The cream
line to cream volume is reduced progressively with increase in the
temperature time of heating.
Which test
is used to detect inadequate pasteurization-----Phosphates Test
Pasteurization
temp of in-bottled pasteurization-----63-66 for 30 min.
Advantage
of in-bottled pasteurization-----Prevent possibility of
post pasteurization contamination.
As vat
heating/cooling is rather slow and involves too much agitation causing
churning and impairment of creaming properties, these operation can be
efficient carried out by plate or tubular heat exchanger.
HTST
pasteurization was first developed by A.P.V.Co. In the United Kingdom in1
992.
Sequence of
HTST pasteurization system-----Balance tank>Pump>regenerative
heating>regenerative cooling>cooling by chill water or brine.
Function of
FCBT----maintain a constant head of milk for feeding the raw milk pump:also
receive any sub temp milk diverted by FDV.
In HTST
pump is fitted between-------- Regenerator and heater.
The PHE is
also called Para flow.
Space
between PHE plates--------3 mm
Normal
pressure maintain in the HTST system are: Pasteurized milk—15psi Raw
Milk---14 psi, Heating cooling medium----12-13 psi
The holding
time is calculated between-----the point at which the heated milk is leave
the heating section and reaches the FDV.
Which
method is used for the determination of holding
time----electrical conductivity method, the dye injection method, the
electronic timer method.
Vacuum pasteurization/Vacreation----Pasteurization
of milk/cream under reduced pressure by direct steam.
Vacreation
process was first developed in New Zealand by M/s Murray Deodorizers Ltd.
Vacreation
was designed to removed Feed and other volatile flavours from cream and
pasteurized it for butter making
Stassanization
is carried out in a tubular heat exchanger consisting of three concentric
tubes.
Stassanization
was first invented in France by Henri Stassano.
What is the
principle behind the Stassanization-----Heating of milk to the desired
temp by passing it between two water heated pipes through the narrow space
of 0.6-0.8 mm.
Heating
temp in Stassanization-----74 for 7 sec.
Ultra-high
Tem Pasteurization----was developed in 1 950s.
Temp/time
combine in ultra-high temp past-----1 35-1 50 (275-302 F) c for no
hold.
Uperization
this is itself a shortened form of the word Ultra Pasteurization’.
In
Uperization the milk is heated with direct steam up to 1 50 (302 F)
for fraction of second. It is continuous process.
Nitric acid
may be used in not more than 1 % for stainless steel surfaces.
Ex of
polyphosphates and chelating chemicals------------------ Tetra phosphates,
hexametaphosphates, tripolyphosphates, pyrophosphates.
Surface
active agents-------Teepol, Acinol-N, Idet-1 0, common soaps
Commonly
used dairy sanitizers are-----steam, hot water, and chemicals (QAC, idophor)
The method
of sanitization broadly consists of ---- flushing, spraying, brushing,
fogging, sub immersion.
Who
invented the Toned Milk----Dr. D.N khurody (India) first produced in 1946
in central Dairy of Aarey milk colony.
