Milk Hygiene

Question 1

Cow Milk Composition

Answer 1

~ 13 % solids (protein, CHO, fat, minerals, vitamins)

~ 87 % water

Question 2

Grade A milk is defined and regulated by

Answer 2

(PMO) Pasteurized Milk Ordinance

Question 3

Grade B Milk

Answer 3

more lax

Question 4

Dairy products such as cheese, butter, ice cream are made from what?

Answer 4

Grade A Milk

Question 5

what does NCIMS stand for ?

Answer 5

National Conference on Interstate Milk Shipments

Question 6

Milk Hazards

Answer 6

Milk is not bacteriologically sterile
mastitis organisms, bacteria in teat canal, skin,
Post harvest contamination
Antibiotics, pesticides, colostrum, off-flavors,

Question 7

Pasteurized Milk ordinance of grade A milk leaving farm?

Answer 7

cooled to 7C ( 45F) within 2 hours
somatic cell count < 750,000 / mL
bacterial count < 100,000 / mL
No positive drug residue test

Question 8

Causes of High Bacterial counts

Answer 8

milking dirty cows
cleaning water temp, and volume
cracked rubber parts, dirty gaskets
Bio ( in bulk tank) or inadequate cleaning of it 
Mastitis bacteria

Question 9

What kind of teats should be milked?

Answer 9

Clean Dry treats

sanitation is important for the premisses, cows, & worker

Question 10

Storage and Transport of Milk

Answer 10

Under the PMO milk is

Stored : refrigerated stainless steal, bulk tanks up to 4 Days
Transport via insulated tanker trucks
tank is residue tested before unloaded
Receiving milk station analyzes for
bacteria/somatic count, & composition (fat and others)

Question 11

What it used to sort out the liquid

Answer 11

Clarifier = removes sediment
dirt, straw, blood, somatic cells, manure
DOES NOT REMOVE BACTERIA

Separator = separate milk with different fat amounts
(skim, 1%, 2%, cream)

Question 12

Pasteurization of Milk

Answer 12

Brief heating to kill common milk pathogens
Destroy pathogens
inactivates enzymes ( lipase)
enhance shelf li

Question 13

Pasteurization of milk is based on thermal death of what?

Answer 13

Coxiella burnetii

Question 14

Batch pasteurization

Answer 14

entire vat heated and held at temp for appropriate time

         Long time holding (LTH) 
               63 C ( 145F) for 30 minutes

Question 15

Continuous Flow pasteurization

Answer 15

Milk flows through heated tube
monitor transit time and temp
less “cooked” flavor than batch pasteurizing

Question 16

Pasteurization

Answer 16

the Homogenizer and pasteurizer are a unit

1. milk enter pasteurizer (heat regeneration section)
   heated by hot milk in holding section
2. Warmed milk piped to Homogenizer then back to the
   holding section.
3. Enters regeneration side to warm incoming milk
4. Finally sent to cooling side
   emerge as cold, homogenized, pasteurized milk

Question 17

Standards for Grade A pasteurized milk?

Answer 17

After pasteurization 
      cooled and maintained to < 45 F
      < 20,000 bacteria / mL 
      < 10 coliform bacteria / mL
      Negative phosphatase test

Question 18

Gold standards of Cheese and cottage cheese?

Answer 18

< 10 coliform / mL

there are no bacterial limits

Question 19

Microbe sources of milk?

Answer 19

Udder infections (mastitis / systemic dz)
Exterior of animal 
Air 
milk equipment and water 
personnel

Question 20

Mastitis definition and associated bacterial causes ?

Answer 20

inflammation of udder
S. aureus
Streptococci ssp.
E. coli
Klebsiells
Mycoplasma spp.
Serratia spp.

Question 21

Mastitic Milk

Answer 21

Mastitis
increased blood protein and leukocytes
decreased milk yield

(mostly subclinical cases)

Question 22

Somatic Cell Count

Answer 22

Somatic cells (leukocytes) / mL of milk

< 100,000 / mL = healthy milk

Question 23

Mastitis cases have ________ SCC and _____- production

Answer 23

high SCC

low production

Question 24

Clinical mastitis

Answer 24

SCC = millions

( 30% loss in milk production)

Question 25

SCC maximum in bulk milk tank

Answer 25

750,000 / mL

lower in EU (400,000) and Canada (500,000)

Question 26

Mastitis screening tests

Answer 26

California mastitic test (CMT) = #1 cowside test

electrical conductivity
Mammary assoc. amyloid A (acute phase protein)
Bacterial culture
bulk tank or indiv. cows

Question 27

Unpasteurized Milk Sales

Answer 27

Believe pasteurization causes
loss of nutrients
milk allergies

ILLEGAL in most states
“ Cow shares”