Milk Hygiene Flashcards
Cow Milk Composition
~ 13 % solids (protein, CHO, fat, minerals, vitamins)
~ 87 % water
Grade A milk is defined and regulated by
(PMO) Pasteurized Milk Ordinance
Grade B Milk
more lax
Dairy products such as cheese, butter, ice cream are made from what?
Grade A Milk
what does NCIMS stand for ?
National Conference on Interstate Milk Shipments
Milk Hazards
Milk is not bacteriologically sterile
mastitis organisms, bacteria in teat canal, skin,
Post harvest contamination
Antibiotics, pesticides, colostrum, off-flavors,
Pasteurized Milk ordinance of grade A milk leaving farm?
cooled to 7C ( 45F) within 2 hours
somatic cell count < 750,000 / mL
bacterial count < 100,000 / mL
No positive drug residue test
Causes of High Bacterial counts
milking dirty cows cleaning water temp, and volume cracked rubber parts, dirty gaskets Bio ( in bulk tank) or inadequate cleaning of it Mastitis bacteria
What kind of teats should be milked?
Clean Dry treats
sanitation is important for the premisses, cows, & worker
Storage and Transport of Milk
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)
What it used to sort out the liquid
Clarifier = removes sediment
dirt, straw, blood, somatic cells, manure
DOES NOT REMOVE BACTERIA
Separator = separate milk with different fat amounts
(skim, 1%, 2%, cream)
Pasteurization of Milk
Brief heating to kill common milk pathogens
Destroy pathogens
inactivates enzymes ( lipase)
enhance shelf li
Pasteurization of milk is based on thermal death of what?
Coxiella burnetii
Batch pasteurization
entire vat heated and held at temp for appropriate time
Long time holding (LTH)
63 C ( 145F) for 30 minutes
Continuous Flow pasteurization
Milk flows through heated tube
monitor transit time and temp
less “cooked” flavor than batch pasteurizing
Pasteurization
the Homogenizer and pasteurizer are a unit
- milk enter pasteurizer (heat regeneration section)
heated by hot milk in holding section - Warmed milk piped to Homogenizer then back to the
holding section. - Enters regeneration side to warm incoming milk
- Finally sent to cooling side
emerge as cold, homogenized, pasteurized milk
Standards for Grade A pasteurized milk?
After pasteurization
cooled and maintained to < 45 F
< 20,000 bacteria / mL
< 10 coliform bacteria / mL
Negative phosphatase testGold standards of Cheese and cottage cheese?
< 10 coliform / mL
there are no bacterial limits
Microbe sources of milk?
Udder infections (mastitis / systemic dz) Exterior of animal Air milk equipment and water personnel
Mastitis definition and associated bacterial causes ?
inflammation of udder S. aureus Streptococci ssp. E. coli Klebsiells Mycoplasma spp. Serratia spp.
Mastitic Milk
Mastitis
increased blood protein and leukocytes
decreased milk yield
(mostly subclinical cases)
Somatic Cell Count
Somatic cells (leukocytes) / mL of milk
< 100,000 / mL = healthy milk
Mastitis cases have ________ SCC and _____- production
high SCC
low production
Clinical mastitis
SCC = millions
( 30% loss in milk production)
