Milk Hygiene Flashcards
composition of cow milk
mixture of fats, proteins, carbohydrates, minerals, vitamins and water
NCIMS
National Conference on Interstate Milk Shipments
grade A milk
defined and regulated by the Pasteurized Milk Ordinance
milk for liquid consumption and any milk in interstate commerce
cheese, butter, ice cream and other dairy products are made from Grade A
True/False: milk is biologically sterile
False:
- mastitis organisms
- bacteria in the teat canal
- bacteria from the skin of the teat
- post-harvest contamination
causes of high bacterial counts
Milking dirty cows Cleaning water temperature and volume Cracked rubber parts Dirty gaskets Biofilm, particularly in bulk tank Inadequate cleaning of bulk tank. mastitis bacteria
sanitation
starts with the premises (milking parlor, equipment, yard/pasture)
cows (udder, flanks bellies, tails; teat dip)
personnel (hand washing!)
storage
Milk is stored on the farm in refrigerated, usually stainless steel, bulk milk tanks
Under the PMO milk may be stored for up to 4 days in this tank
transport
insulated tanker trucks
tested for antibiotic residues before it is unloaded
may pick up from more than one farm
milk receiving station
Milk is analyzed for bacteria, somatic cell counts, and composition (fat and other components)
clarifier
remove sediment
Removes dirt, straw, blood, somatic cells, manure, NOT bacteria
separator
separate milk with different amounts of fat
pasteurization
Brief heating is used to kill common pathogens in milk; milk is not sterile
Pasteurization is currently based on the thermal death of Coxiella burnetii
Batch pasturization
Entire vat is heated and held at temperature for the appropriate length of time
continuous-flow pasturization
Milk flows through a heated tube, with a carefully monitored transit time and temperature
Less of a “cooked” flavor than seen with batch methods
true/false: for cheese and cottage cheese there is no bacterial limit
true; coliform
after pasteurization
Cooled to
sources of microbes
Udder: infections of the udder Exterior of animal: dirt/mud, feces, hair, etc. Air: dusts, aerosol, etc Milking equipment Personnel Water
mastitic milk
Increased blood proteins and leukocytes in milk
Decreased milk yield
true/false: 5-10% of cows may produce abnormal milk at any one time
true
mastitis cases=
high SCC and low production
legal maximum SCC for Grade A cow’s milk in the USA
750,000 cells/mL
1 cowside test for mastitis
California mastitis test (CMT)
mastitis screening test
California mastitis test (CMT)
Electrical conductivity
Mammary associated amyloid A
Bacteriologic cultures
sale of unpasteurized milk
Belief that nutrients are lost by pasteurization
Belief that pasteurization causes milk allergies
Illegal in most states
“Cow- Shares”
