Milk Hygiene (final material) Flashcards Preview

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Flashcards in Milk Hygiene (final material) Deck (29)
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1

What is cow milk composed of?

Fats
proteins
Carbohydrates
minerals
vitamins
water (87%)

2

What is Grade A milk defined as?

Defined and regulated by the Pasteurized Milk Ordinance

for liquid consumption and any milk in interstate commerce

*most cheese, butter, ice cream, and other dairy products are made from Grade A milk

3

T/F: Milk is bacteriologically sterile

FALSE

May contain:
Mastitis organisms
Bacteria in the teat canal
Bacterial on the skin of the teat (staph/strep)
Post harvest contamination

4

What are other (non-bacterial contaminants) that can be found in milk?

Antibiotics and other drugs
Pesticides
Colostrum
Off-flavors
other aldulterants

5

What steps are taken on the farm, following the PMO, after milking?

Cooled to 45F within 2 hrs
Somatic cell count must be less than 750,000/ml
Bacterial count must be less than 100,00 ml
No drug residue

6

What are some causes of high bacterial counts within milk?

Milking dirty cows
Cleaning water temp and vol.
Cracked rubber parts
Dirty gaskets
Biofilm in bulk tank
Inadequate cleaning of bulk tank
Mastitis bacteria

7

What bacteria present in milk would lead you to suspect fomite contamination from human hands?

Staph. auerus

8

Sanitation begins with the _________

Premises

1.Milking parlor and all the equipment inside should be easy to clean
2. Yard/pasture for cows should have no standing pools of water or feces
3. Appropriate bedding for cows

9

Sanitation also applies to _____ and _________

Cows and personnel

10

Before milking, what should be done to the teats?

They should be sanitized and dried

11

Under the PMO, how long may milk be stored in the bulk tanks on the farm?

Up to four days
*these are refrigerated

12

How is milk transported?

Insulated tanker trucks

The tanker load is tested for antibiotic residues before it is unloaded

13

T/F: Tanker trucks transporting milk may pick up from more than one farm

TRUE

14

What occurs at the milk receiving station?

Milk is analyzed for bacteria, somatic cell counts, and composition (fat and other components)

15

What is the clarification process of milk?

Clarifier = remove sediment

Milk is pumped through a centrifugal device to remove large particulate matter (dirt, straw, blood, somatic cells, manure)

16

Does the clarifier remove bacteria from milk?

NO

17

What is the function of the milk separator?

Separates milk with different amounts of fat

This is also based upon cetrifugation

18

What is the basic process of pasteurization of milk and why is it done?

Using heat (for certain periods of time) to kill common pathogens in milk, inactivate enzymes in milk, enhance shelf life

19

Pasteurization is currently based on the thermal death of what pathogen?

Coxiella burnetii

20

What is batch pasteurization? What temp is used and for what time?

An entire vat is heated and held at temperature for the appropriate length of time.

63C/145F for 30 min

21

What is the process of continuous flow pasteurization?

Milk flows through a heated tube, with a carefully monitored transit time and temperature

results in less of a "cooked" flavor than batch methods

Temps range from 72C/161F - 100C/212F for short periods of time (12sec - 1 sec - 0.5sec)

22

After pasteurization, what temp is milk cooled to and maintained at?

less than 45F

should contain less than 20,000 bacteria/ml and less than 10coliform bacteria/ml

phosphatase test must be negative

23

T/F: For cheese or cottage cheese, pasteurized milk has no bacterial limit; just coliform limit of less than 10/ml

TRUE

24

Where do microbes found in cow milk come from?

Mastitis or systemic infections
Dirt/mud, feces, hair on exterior
Dusts, aerosols
Milking equipment
Personnel
Water

25

What percentage of dairy cow may produce abnormal milk due to subclinical mastitis at any one time?

5-10%

milk will be increased in blood proteins and leukocytes and there will be a decrease in production

26

What should the somatic cell count of healthy milk be?

less than 100,000/ml

automated machine counters are used for this data

27

What somatic cell count may you expect in a subclinical case of mastitis? And in a clinical case?

Subclinical = greater than 200,00

Clinical = SCC in the millions **30% loss in milk production per day

28

What is the legal maximum SCC in the bulk milk tank?

750.00 cells/ml - USA
(limits are lower in Europe and Canada)


*mean for US dairies = ~230,000 cells/ml

*lower in winter than in summer, in western US and large dairy herds

29

What is the number one cow side mastitis test?

California mastitis test (CMT)


*other tests include - electrical conductivity, mammary associated amyloid A, Bacterial cultures