Public Health: Milk Quality

Front 1

Follow the path of milk from the teat to the bulk tank

Back 1

Teat, inflation, short milk tube, bowl, long milk tube, milk line, receiver jar, cooling plates, milk sock filter, bulk tank

Front 2

Who is responsible for sampling milk for antibiotic testing?

Back 2

The driver of the milk truck

Front 3

Which drug class is each milk truck load tested for?

Back 3

B-lactam antibiotics

Front 4

Does high fiber or high concentrate lead to a higher milk butterfat content?

Back 4

High fiber

Front 5

How does a high grain diet affect milk butterfat content?

Back 5

Suppresses fat content

Front 6

Between the receiver jar and the bulk tank, the milk passes through the...

Back 6

Milk sock

Front 7

Between the inflation and the bowl, milk must pass through the...

Back 7

Short milk tube

Front 8

List the milk quality standards for Grade A milk.

Back 8

1.Milk should not have objectionable odors
2. Bacteria count under 100,000/mL
3. No drug residue
4. SCC under 750,000
5. Bulk milk tank will be at 40 F or less within 2 hours of milking and remain this cool until next milking.

Front 9

Jersey milk has what % butterfat?

Back 9

4-4.5%

Front 10

Holstein milk has what % butterfat?

Back 10

3-3.5%

Front 11

What is removed from milk at the plant and then added back in?

Back 11

Fat

Front 12

Whole milk has what % butterfat? Fat grams per cup?

Back 12

3.5%, or 8g/c

Front 13

Skim milk has what % butterfat? Fat grams per cup?

Back 13

0.1%, or 0.5 g/c

Front 14

2% milk has how many fat grams per cup?

Back 14

5g/c

Front 15

What constitutes SNF, or solids non fat?

Back 15

Ash/mineral, carbohydrates, and protein

Front 16

Water makes up what % of milk?

Back 16

86%

Front 17

How is milk tested for added water? Describe.

Back 17

Cryoscope test: Milk freezing point is normally -0.54 C. If truckload freezes at -0.535 C or above, each sample checked for added water individually.

Front 18

Transitional milk is discarded for how long?

Back 18

5-6 milkings, or 3-4 days

Front 19

List four factors that may cause milk to have a bad flavor or odor.

Back 19

1. Feed and weed flavors (garlic, alfalfa, etc)
2. Barny flavors (poorly ventilated barn, poorly cleaned milking equipment)
3. Rancid flavors (FFA's freed by enzymes during excessive agitation of milk)
4. Foreign flavors (chemicals)

Front 20

List two ways in which milk is tested for bacteria.

Back 20

Standard Plate Count
Preliminary Incubation Test (PI Test)

Front 21

Which method of bacterial quantification gives the best estimate of shelf life?

Back 21

Preliminary Incubation (PI) Test

Front 22

The bacterial counts gotten by the PI test are indicative of what?

Back 22

Sanitary conditions on the farm

Front 23

Describe the PI test method and cutoff bacterial values.

Back 23

Incubate milk at 55 F for 18h, then plate. Counts must be under 100,000, but ideally under 20,000.

Front 24

Describe the Standard Plate Test and cutoff bacterial values.

Back 24

Plated and incubated at 32 C (90 F) for 48h.
Legal maximum is 100,000. Most farms under 10,000.

Front 25

What kind of bacteria are killed by pasteurization?

Back 25

Pathogenic bacteria

Front 26

List three groups of bacteria present in raw milk.

Back 26

Thermoduric bacteria
Psychrotropic bacteria
Spore formers

Front 27

Which groups of bacteria survive pasteurization?

Back 27

Thermoduric bacteria
Spore formers

Front 28

These bacteria grow at refrigeration temperatures.

Back 28

Psychrotropic bacteria

Front 29

What kind of bacteria are Lactobacilli and Enterobacilli?

Back 29

Thermoduric

Front 30

These bacteria produce enzymes that are not destroyed by pasteurization and produce "off" flavors in milk.

Back 30

Psychrotropic

Front 31

Clostridium and Bacillus belong to this bacterial group.

Back 31

Spore formers

Front 32

Milk produced under sanitary conditions will have as little as 10% of the total microflora as this group.

Back 32

Psychrotrophs

Front 33

Majority of bacteria detected on PI count belong to this group.

Back 33

Psychrotrophs

Front 34

Primary sources of bacteria in milk

Back 34

Air, dust, dirty equipment

Front 35

List 4 areas in which milk contamination may occur.

Back 35

1. Unclean cow
2. Milking practices
3. Milking equipment
4. Bulk tank

Front 36

List some factors relating to the cow's role in milk cleanliness.

Back 36

Cow housing: Freestall design and maintenance, lot design, alleyways
Cow clipping or singeing

Front 37

Cow clipping or singeing reduces milk bacteria by up to...

Back 37

45-75%

Front 38

Describe milking practices that reduce bacterial contamination of milk.

Back 38

Wash cow teats, not udder
Use disinfectants in water
Dry with individual towels

Front 39

Describe how milking equipment is cleaned after each milking.

Back 39

Hot water
Alkaline or chlorinated cleaner for organic soils
Acid wash for mineral soils where thermoduric bacterial live
Pre-milking sanitization

Front 40

The bulk tank must cool milk to what temperature within what time?

Back 40

40 F within 2 hours

Front 41

Describe the bulk tank cooling system.

Back 41

In-line heat exchangers cool milk enterint tank and heat surrounding water
Dual compressors, one at either end of tank

Front 42

Process by which raw milk is rendered safe for human consumption

Back 42

Pasteurization

Front 43

Pasteurization temperature is set to kill this organism.

Back 43

Coxiella burnetti

Front 44

Test done to ensure that pasteurization has taken place

Back 44

Alkaline phosphatase activity measurement

Front 45

Traditional (home-dairy) method of pasteurization

Back 45

145 F for 30 mins

Front 46

Method of pasteurization used by most commercial dairies today

Back 46

161 F for 15 sec

Front 47

Method of pasteurization used to sterilize boxed UHT milk.

Back 47

280 F for 2 sec

Front 48

Test used to measure udder health and inflammation.

Back 48

Somatic cell counts

Front 49

SCC cutoff value for no infection

Back 49

150,000/mL

Front 50

SCC cutoff for possible infection

Back 50

150K-500K

Front 51

SCC cutoff for probable infection

Back 51

>500,000/mL

Front 52

Legal maximum SCC for interstate transport

Back 52

750,000/mL

Front 53

How is milk tested for antibiotic residue? List two ways

Back 53

Inhibition of bacterial growth
Immunologic tests (Penzyme, CHARM)

Front 54

Farmer Bob's milk is determined to contain drug residures that have contaminated the truckload. What consequences does he face?

Back 54

The load will be dumped and Farmer Bob will have to pay for it!

Front 55

Test used at the milk plant to detect foreign particles.

Back 55

Sedimentation test

Front 56

Way particulate matter is removed from milk at the farm

Back 56

Milk sock