Module 7-fluid milk products and processing

Question 1

what are the two processing streams is milk collected and classified as

Answer 1

fluid milk and industrial milk

Question 2

what is fluid milk

Answer 2

Fluid milk is any milk product considered to be a beverage

Question 3

what is industrial milk

Answer 3

Industrial milk is milk used to make dairy-derived products such as cheese, yogurt, butter, ice cream, evaporated milks, dehydrated products and whey products

Question 4

how much milk is destined to be fluid milk

Answer 4

Forty percent of dairy production in Canada is directed toward fluid milk products

Question 5

what is included in fluid milk

Answer 5

Fluid milk products include table milks, flavoured milks and cream

Question 6

what are the more recent specialty milk beverages that have been developed to meet evolving consumer demand

Answer 6

New products include low-lactose and lactose-free milk for people sensitive to lactose, probiotic milk, and milks fortified with plant sterols, protein, calcium, and vitamins

Question 7

what is the fat content of whole milk

Answer 7

fat content of whole milk is 3.8%

Question 8

what do table milks include

Answer 8

Table milks including skim milk, 1% milk, 2% milk, and 3.25% milk are reduced in fat content relative to whole milk (3.8 % fat)

Question 9

how much fat do the creams have

Answer 9

cream milk or half and half (10% fat) or whipping cream (35% fat)

Question 10

whats in flavoured milks and how are they made

Answer 10

they have sugar, flavour and colour as well as stabilizer added before pasteurization

Question 11

what is shelf stable milk

Answer 11

Shelf stable milk is provided as a substitute for fresh milk that does not require refrigeration

Question 12

what is the shelf life of shelf stable milk

Answer 12

Shelf stable milk can be kept without refrigeration for up to nine months unopened and up to twenty days refrigerated after opening.

Question 13

what is the clarification process

Answer 13

particulate matter removed by centrifugation

Question 14

what is the standardization process

Answer 14

fat content is adjusted to desired level

Question 15

what is the victimization process

Answer 15

fat-soluble vitamins A & D are added

Question 16

what is the pasteurization process

Answer 16

pathogenic microbes destroyed by heating milk

Question 17

what is the homogenization process

Answer 17

reduction of size in fat globules in milk

Question 18

what is the packaging process

Answer 18

the final milk products are packaged in cartons, bags, bottles or jugs

Question 19

what happens to milk during clarification

Answer 19

the milk is centrifuged at high speeds to remove particulates that may be found in the whole milk

Question 20

what things are being sorted out during clarification

Answer 20

Particulates can include blood cells, bacteria, skin cells from the cow’s udder and dust particles

Question 21

what happens inside the machine during clarification

Answer 21

Spinning the milk sends the non-milk solids to the periphery of the clarifier where it collects as clarifier sludge. The sludge is automatically discharged from the clarifier periodically

Question 22

what is standardization necessary for

Answer 22

its necessary to adjust the fat content of the milk to the desired level (0, 1, 2 or 3.25%) by removing part or all of the butterfat

Question 23

what are high-speed centrifugal separators used for

Answer 23

Centrifugal separators, operating at a higher speed than those used for clarification are used to separate the cream portion from the aqueous phase of the milk

Question 24

what is slow and high speed centrifugation used for

Answer 24

Slow speed centrifugation is used to clarify the milk by removing small particles of debris and high speed centrifugation is used to separate out the butterfat

Question 25

what two milk processes can be carried out simultaneously

Answer 25

The clarifying and standardizing operations may be carried out simultaneously

Question 26

why do vitamins need to be added to milk

Answer 26

Fat soluble vitamins (Vitamins A and D) are added to the milk to compensate for seasonal variations in concentration and for losses which occur when butterfat is removed during standardization

Question 27

when and why are vitamins added to milk

Answer 27

The vitamins are added before pasteurization so that any pathogens present in the vitamin preparations will be destroyed.

Question 28

how is pasteurization done

Answer 28

Milk is pasteurized through a heating process designed to destroy pathogenic microbes as well as nonpathogenic microbes that might hasten spoilage of the milk

Question 29

how does pasteurization help reduce milk spoilage

Answer 29

Pasteurization also lowers the activity of deteriorative enzymes that contribute to milk spoilage

Question 30

what is low-temperature-hold pasteurization

Answer 30

Low-temperature-hold (LTH) pasteurization involves heating milk to a minimum of 63°C in a stirred, covered vat; the temperature is maintained for at least thirty minutes

Question 31

when is low temperature-hold pasteurization used for

Answer 31

LTH pasteurization is used in batch pasteurization systems for lower volume specialty products such as egg nog

Question 32

how is most milk pasteurized

Answer 32

Most milk is pasteurized in high-temperature short-time (HTST) systems heating the milk to 72°C and maintaining this temperature for 15 seconds through a plate heat exchanger

Question 33

how are high sugar milk products treated and why?

Answer 33

Products with higher levels of fat and/or sugar are treated at higher temperatures and/or for longer times because the fat and sugar protect the microorganisms from the denaturing effects of heat

Question 34

what pathogens are being destroyed for pasteurization heat treatment

Answer 34

The standard for pasteurizing heat treatment is the destruction of the bacterium Coxiella burnetti, the most heat stable pathogen of concern that is found in fresh milk. C. burnetti is the causative agent of Q fever

Question 35

does pasteurization effect the milk flavour or nutrients

Answer 35

Pasteurization is a relatively mild thermal process that does not alter the flavour or colour of milk or destroy nutrients contained within the milk

Question 36

what is ultra-high temperature pasteurization used for

Answer 36

Ultra High Temperature (UHT) processing is used to manufacture shelf stable milk that does not require refrigeration

Question 37

what temperature and time duration is the ultra-high temperature at

Answer 37

The UHT system involves heating milk to 140°C for five seconds

Question 38

is ultra-high temperature milk popular in Canada? where is it really popular?

Answer 38

UHT milk has not been popular in the Canadian market although it comprises more than eighty percent of the milk market in some European countries

Question 39

what does homogenization do to milk

Answer 39

Homogenization of milk reduces the size of the fat globules to prevent them from coming together and rising to the surface of the milk during its useful storage life

Question 40

what does the process of homogenization involve

Answer 40

The process involves pumping the milk through a series of homogenization valves at high pressure. The homogenization valves reduce the size of the globules by a combination of shearing and impact

Question 41

after homogenization what prevent the globules from returning to the there original size

Answer 41

The smaller globules are coated with casein which helps prevent them from interacting and coalescing.

Question 42

what heat may be used to standardize the milk flavor

Answer 42

A brief heat (90-95°C) vacuum treatment may be employed to standardize the flavor of the milk

Question 43

what are most off flavours of milk associated with

Answer 43

Most off-flavours are associated with seasonal variations following dietary changes

Question 44

how is flavour standardization applied

Answer 44

The flavor standardization treatment is usually applied to hot, pasteurized milk as it leaves the heat-holding section

Question 45

what else happens when heat is added to help with the standardization of milk

Answer 45

This treatment also extends the shelf life of the milk products

Question 46

what is the shelf life of processed milk

Answer 46

The packaged product has a refrigerated shelf life of at least two weeks if it is maintained at temperatures below 4.5°C

Question 47

what is flavoured milk

Answer 47

Flavoured milks are partially skimmed milks (1 or 2%) with added flavor, sugar and a stabilizer such as vegetable gum to improve the creaminess and keep flavouring particles from settling to the bottom of the container during storage

Question 48

when is the additional ingredient of flavoured milk added

Answer 48

The additional ingredients are incorporated into the milk before pasteurization or UHT sterilization

Question 49

does flavoured or regular milk require more pastrization

Answer 49

Flavoured milks require more pasteurization treatment than regular milks because of their high sugar content

Question 50

how are coffee cream and whipping cream prepared

Answer 50

Coffee cream (10% butterfat) and whipping cream (35% butterfat) are prepared by blending the cream fraction removed from fresh milk with an appropriate amount of skim milk

Question 51

what requires more pasteurization coffee cream and whipping cream or fluid milk? why?

Answer 51

Both coffee cream and whipping cream require more extensive pasteurization than fluid milks because of their higher fat content

Question 52

when is coffee cream homogenized

Answer 52

Coffee cream is homogenized after pasteurization to prevent fat separation during storage and to increase its viscosity

Question 53

when is whipping cream homogenized

Answer 53

Whipping cream is not homogenized because the process would destroy its whipping properties