Htst, Hhst, And Up Q& A's

Front 1

What is the minimum temperature for milk, cream, and ice cream pasteurized by the HTST method?

Back 1

Milk- 161 degrees F; held for at least 15 sec

Cream- 166 degrees F; held for at least 15 sec

Ice Cream- 175 degrees; held for at least 25 sec

Front 2

What is required upon start up if an HTST with multiple cut-in and cut-out temperature set points?

Back 2

shall be checked for each temperature range to be used

Front 3

What is a "Safety Thermal Limit Recorder?'

Back 3

pasteurization temperature recorder controller

Front 4

If the pasteurization temperature recording chart on an HTST is not recording within 1 degree F, what is the licensed pasteurizer required to do?

Back 4

adjust temp. recording chart to within 1 degree F of indicating thermometer.

NOTE: temp. recording chart should not read higher than indicating thermometer

Front 5

Shall the pasteurization temperature recording charts always be marked in sequence?

Back 5

Yes, to make chronological documentation o/ products easier to follow

Front 6

Who has the authority to adjust the pasteurizer temperature recording charts pen?

Back 6

licensed pasteurizer operator or any trained person under request of licensed pasteurizer operator

Front 7

When in operation, what does the green (amber) light on the HTST recorder controller indicate?

Back 7

forward flow of FDD

Front 8

While in forward flow, failure of electricity would cause the FDD to do what?

Back 8

take diverted position

Front 9

What is the meaning of the term "Fail Safe Valve" in reference to an HTST FDD?

Back 9

FDD is spring loaded to take the diverted position in case of air loss or power failure

Front 10

What is the function of micro switches in the FDD?

Back 10

to indicate the position of the FDD and supply power to the timing pump

Front 11

What is the possible cause if upon start up, the timing pump will not run and the pasteurization temperature recorder- controller light indicates no lights are lit on the pasteurizer temperature recorder panel on an HTST?

Back 11

micro switch on leak detector valve is out of alignment or the valve is not seated properly

Front 12

What is the possible cause if upon start up, the timing pump will not run and the pasteurization temperature recorder-controller light indicates forward flow?

Back 12

divert valve micro switch is out of alignment or valve is not properly seated

Front 13

What is the flush delay on a dual stem FDD?

Back 13

the time delay between movement of the flow diversion valve and the leak detector valve when the pasteurizer goes into forward flow

Front 14

How long is the flush delay on an HTST with a positive pump?

Back 14

1-2 sec

Front 15

What controls the flow rate of an HTST pasteurizer

Back 15

speed of timing pump

Front 16

Where is the raw balance tank of an HTST having a raw product to pasteurized product regenerator section located?

Back 16

upstream with its overflow below the bottom of the regenerator section

Front 17

What is the effect of by-passing the HTST raw regenerator section in diverted flow?

Back 17

it aids in the start up of the HTST system by going directly to the heating section

Front 18

What 3 elements are important in HTST pasteurization with a regenerator section?

Back 18

time, temperature, and pressure

Front 19

What is the function of the HTST pressure differential controller?

Back 19

to control the booster pump

Front 20

What is the function of the HTST booster pump?

Back 20

to increase the flow rate through the raw milk section of the regenerator

Front 21

When may the booster pump on an HTST run?

Back 21

when:

1. timing pump is running
2. system is in forward flow
3. pressure differential(s) is correct

Front 22

What controls the back pressure for the HTST regenerative section?

Back 22

by a valve downstream from the outlet of the pasteurized side of the regenerator

Front 23

What is the deflector plate in the HTST regenerator section?

Back 23

ised to change direction of product flow inside the regenerator?

Front 24

Why is a visible, sanitary restrictor used in the diversion line of an HTST?

Back 24

to compensate for lost head pressure in divert when product doesn't travel through the regenerative cooling sections

NOTE: should be installed in vertical position

Front 25

What should the pasteurizer operator do if the product is seen flowing through the sight glass in diverted flow?

Back 25

notify their supervisor, shut down the pasteurizer and replace the defective FDD valve(s)

Front 26

What is one purpose of a stuffing pump in an HTST system?

Back 26

can be used to constantly feed the homogenizer

Front 27

Shall the vitamin pump in an HTST system run if the unit is diverted or in recycle?

Back 27

No, it doesn't run in divert flow or recycle to prevent exceeding the maximum allowable vitamin levels

Front 28

Shall a separator on the pasteurized side of an HTST pasteurizer be valved out of the system during diverted flow and loss of power?

Back 28

Yes, to eliminate negative pressure between the outlet of the holding tube and the separator, because the separator is a flowing promoting device

Front 29

What items are required to be sealed on an HTST?

Back 29

those that may affect public health

NOTE-
includes:
1. pasteurization cut-in and out temp.
2. hold time of product
3. pressure between raw and pasteurization sides of the regeneration sections
4. required time delays
5. a computer, if used for the legal public health controls
6. air valves if present at FDD
7. spiced wiring for RTD's or pressure differentials

Front 30

When may regulatory seals be broken?

Back 30

by personnel who need to repair a control under seal

Front 31

What is the function of the magnetic flow meter?

Back 31

measures rate of flow

Front 32

What is the function of the frequency pen on a magnetic flow meter recorder?

Back 32

indicates:
1. legal speed
2. when flow is higher than the high alarm set point or lower than the low alarm set point

Front 33

May the pump in metering based timing systems be either fixed or variable speed?

Back 33

true

Front 34

What is the function of the high flow alarm on a meter based timing system?

Back 34

diverts FDD when product flow exceeds a preset value which is set for at least the minimum required time

Front 35

What is the magnetic flow meter forward time delay?

Back 35

the delay after a high or low flow alarm to insure that forward flow shall not occur until all product in the holding tube has been held at or above pasteurization temp. for at least the minimum required holding time

Front 36

What is the minimum time delay when switching to the "CIP" mode?

Back 36

10 min

Front 37

What type of soil will caustic cleaners remove in pasteurizers?

Back 37

fat and proteins

Front 38

What type of soil will acid cleaners remove in pasteurizers?

Back 38

mineral deposits

Front 39

May all HTST vacuum breakers be cleaned in place?

Back 39

No, only approved air actuated vacuum breakers, all others manually disassembled and hand cleaned

Front 40

Why must both valves of the FDD pulse independently during CIP?

Back 40

to ensure that the bottom valve ports of the FDD and both leak detector and flow diversion lines get properly cleaned

Front 41

When shall a pasteurizer be sanitized?

Back 41

after CIP, or prior to each days use

Front 42

During a short or quick CIP of the HTST, is it required to disconnect the product lines

Back 42

Yes, to prevent cross connections between product and chemicals

Front 43

What are minimum time and temperature requirements for fluid milk products pasteurized by HHST method?

Back 43

- at least 191 degrees F (1 sec)
- 194 degrees F (0.5 sec)
- 201 degrees F (0.1 sec)
- 204 degrees F (0.05 sec)
- 212 degrees F (0.01 sec)

Front 44

Where is the FDD located on an HHST pasteurization system?

Back 44

downstream from the cooling section of the HHST

Front 45

What does ultra pasteurized (UP) mean?

Back 45

processed at or above 280 degrees F for at least 2 sec

Front 46

Can aseptically processed milk (UHT pasteurization) be packaged in hermetically sealed containers and stored without refrigeration?

Back 46

Yes, aseptic process which is filed with FDA, sterilizes the product after legal pasteurization by destroying all viable organisms and their spores

Front 47

Shall the UHT pasteurizing process with steam injection or steam infusion, have a ratio controller to prevent water adulteration of the product?

Back 47

Yes, ratio controller controls the amount of water added during steam injection or infusion

Front 48

What is steam injection?

Back 48

steam forced through a properly designed sanitary nozzle into the milk product flow

Front 49

What is steam infusion?

Back 49

spraying milk into a chamber containing steam

Front 50

Where are the UHT pasteurization process ratio controller sensors located?

Back 50

prior to the point of steam injection, and the other located immediately after the product exits the vacuum chamber