Dairy Ingredients for Food Processing

Processing Principles of Dairy Ingredients 115

regeneration section, it can be separated and

homogenized and then the standardized,

homogenized milk enters the second regen-

eration section, where it is further heated by

the hot pasteurized milk. Heating is accom-

plished by using hot water as the medium.

The hot water, in turn, is produced by inject-

ing culinary steam into the water. The steam

is generated in boilers at the dairy factory.

After the regeneration section the milk

enters the pasteurization section where it is

heated to the required temperature. The

heated milk exits the heating section and

enters an external holding tube. The fl ow rate

of hot milk determines the residence time in

the holding tube. The fl ow rate in turn is

controlled by the fl ow controller that was

referred to earlier. After the transit through

the holding tube the exiting milk temperature

is measured and transmitted to a temperature

controller and a recording chart.

milk in the system to the balance tank. The
milk is replaced by water if circulation has
continued for a certain predetermined time.
Milk is pumped from the balance tank to
the plate heat exchanger. The pump is fi tted
with a fl ow controller to ensure that a con-
stant fl ow is maintained at a predetermined
value. This value depends on the characteris-
tics of the pump and the heat exchanger
capacity. The fl ow control device also guar-
antees a stable temperature and constant
length of holding. The fl ow control device
also may be located after the fi rst regenera-
tion section.
Regenerative preheating is an energy -
saving step in pasteurization. Cold untreated
milk is heated by the outgoing pasteurized
milk. Thus, cold milk is preheated and the
hot milk is cooled simultaneously. The regen-
eration section is divided into two sections.
After the cold milk is preheated in the fi rst

Figure 4.13. A complete pasteurizer plant. 1, balance tank; 2, feed pump; 3, fl ow controller; 4, regenerative
pre - heating sections; 5, centrifugal clarifi er; 6, heating section; 7, booster pump; 8, holding tube; 9, hot water
heating; 10, regenerative cooling sections; 11, cooling sections; 12, fl ow diversion valve; 13, control panel;
A, temperature transmitter; B, pressure gauge. Reproduced with permission from Tetra Pak.

12

(^11111010)
B
A
13
1 2
3
44
7
6
5
8
9
Cream
Product
Steam
Heating medium
Cold water
Ice water