Milk Hygiene Flashcards
What 8 step process do most dairies in the US follow to get milk to the consumer? What is the purpose of listing out these steps?
- rearing
- harvesting by hand milking or machine milking
- storing
- transportation
- lab testing for aroma, temperature, pH, and drug residue
- processing
- packaging
- selling
ensures GHP at all steps in the supply chain are followed
What are 11 soures of contamination during milk production? How can these be controlled?
- soiled animal: feces, mud soil
- veterinary residues: drugs, pesticides
- waste: hair, dung, dust, bedding
- building: floor, doors, windows, walls, ceiling
- personnel: dirty hands of milker
- equipment: poor sanitation and maintenance
- pests: flies, ticks, mosquitoes, roaches, rodents, birds
- utility: water, ventilation
- chemicals: metals, organic sanitizers, detergents, disinfectants
- transport: other animals, meat, packaging
- production processes: packaging, labelling
action at CCPs and sanitation/hygiene
What 5 hygienic practices are required to be strictly adhered to by the producers? Why?
- animal hygiene
- milker’s/personnel hygiene
- utensils and equipment hygiene
- milking process hygiene
- environmental hygiene
these are all sources of milk contamination during collection and transport of milk
Why is good bedding especially important? Why is the housing area hygiene important?
helps minimize soiling and improves animal comfort
avoids soiling of the animals and breeding of insects
How should water be available to cows in the facility? How much should be available?
ad libitum (as much or as often as necessary or desired) potable water from a hose with a sufficient volume and force for washing equipment and cows, too
1000-5000 per 1000 L of milk
Why should warm running water be available in milking facilities? How is wastewater disposed?
disinfectant can be added to rinse hands, protective clothing, udders, and equipment when they’re soiled
all drainage is discharged to a suitable drainage system
How should dairy farms be designed? Floors? Doors/walls? Roof/loft floors?
designed so that the risk of contamination from dust flies, birds, and other animals is minimized
impervious to water and free-draining
smooth, impervious, easy to clean
dust-proof sheet material easy to clean
Why is proper ventilation in dairies important? How should they be lit?
provides clean air and avoids condensation
artificial strip lights with shatterproof and waterproof diffusers to provide good visibility for all milking and cleaning operations
How should equipment be cleaned in the milking process? What must be available in milking areas (parlors)?
disinfect with iodine or chlorine before and after milking
potable water for handwashing, udder and teat washing, and rinsing/cleaning equipment
What are some common equipment used for milking, storage, and cooling? How should they be made?
- milking machines
- milk bulk tank (storage, cooling)
- containers, crates
- vehicles, vessels
all contact surfaces must be appropriately cleansed and disinfected immediately after each milking and smooth, washable, non-toxic, and non-corrosive/leeching —> STAINLESS STEEL
What are clean-in-lace systems used for? When are they used?
incorporated into equipment that allows solvents to be run through the system and then flushed clean
time between normal influx of milk from the farms
What are the 7 steps to utensil and equipment hygiene?
- pre-rinsing
- alkaline cleaning
- rinsing
- acidic cleaning
- rinsing
- disinfection
- rinsing
ensure equipment is dry before use
What is the objective of cleaning, clipping, and grooming cows? What 4 areas should especially be cleaned? Why?
removes visible soiling and bacterial that could contaminate milk
- clipping hair around udders, flanks, and tails to reduce bacteria counts in milk
- tail - avoids fly attraction
- body - reduces soiling
- teats and udders - dips/sprays
What is the link between udder and leg hygiene scores and mastitis?
more dirt/soiling = increased chances of mastitis and milk contamination
(cows themselves are a severe source of milk contamination)
What is a common CCP in the milk industry? What is done here?
milking step
sorts cows with 5 D’s and signs of udder problems (mastitis) to reject their milk or cull
What are the 3 legislations concerning different animal species that are sources of milk?
- cows are a universally recognized milk producer for consumption
- milk from other species can be consumed - ewes, does, buffaloes, camels
- mixing and processing milk of different species is considered adulteration
What are the 3 requirements for milk hygiene?
- free from biological hazards
- free from chemical hazards (pesticide and antimicrobial residues)
- free from physical hazards
What are the 6 orders concerning cow health and milk requirements that prevent/control milk contamination?
do not allow the following milk to enter food supply chain:
- milk with abnormal flavor, taste, or odor = DISTORTED
- milk from stressed/emaciated animals = DEVASTATED
- milk from zoonotic diseased animals (TB, brucellosis)
- milk from urogenital tract infected animals, or those with enteritis/fever
- milk from cows with acute purulent mastitis, coma, rabies, cowpox, septicemia
- milk with antibiotic treatment animals without a withdrawal period
What are the 2 types of milking?
- HAND - poured through a strainer following milking and chilled
- MACHINE - machine connected to bulk tanks
(buckets, pails, cans, and bulk tanks are the main sources of milk contamination after it leaves the udder)
What are the 4 main components of hygienic milking?
- personnel/operator hygiene
- equipment hygiene: any soiling of milking equipment must be washed off before re-attachment
- environment hygiene: movement of dusty feeds or bedding should not be carried out close to milking area
- teats, udders, adjacent parts hygiene: must be cleaned before attachment of milk machine
What 3 hygienic practices should occur before milking? After?
- wash udders/teats with disinfectants and dry
- fore-milk to check for physical, chemical, and organoleptic abnormalities (good early detection of mastitis)
- check udder for inflammation (swollen, hot, painful)
dip teats in iodine
What are the 8 steps of machine milking?
- observe cows for signs of illness (sort 5 D’s)
- fore-stripping and udder checking (sort 5 D’s)
- wash and dry teat and udder
- attach milking unit
- adjust unit
- end milking (avoid overmilking that can result in harm to the epithelium)
- remove unit
- disinfection (iodine dip)
What is the most devastating problem in the dairy industry? What are the environmental and contagious factors that cause this?
mastitis
ENVIRONMENTAL - E. coli, Klebsiella pneumoniae, Klebsiella oxytoca, Enterobacter aerogenes
CONTAGIOUS - Mycoplasma bovis, Staph. aureus, Strept. agalactiae, Strept. dysgalactiae
What are the most common microbes in water, feed, soil, bedding, equipment, and outside of udder/teats that can contaminate milk?
WATER - Pseudomonas
FEED - Listeria (silage high in iron)
SOIL - Clostridium, Bacillus
MM - Streptococci, Bacillus, Coliforms
OUTSIDE - G+, Staph, Enterococcus, Bacillus
What are the 3 most important sources of milk contamination?
- teats
- milking machines
- bulk tank
What 4 changes in the teat are caused by mastitis?
- leaking of ions, proteins, and enzymes from blood into the milk due to increased permeability
- invasion of phagocytes into the milk, detected by somatic cell counts (SCC)
- decrease of synthetic capacity of the gland, resulting in decreased concentrations of milk constituents
- production of substances related to inflammatory reaction, like acute phase proteins
What constituents are decreased and increased in milk affected by mastitis?
DECREASED = casein, lactose, fat, whey, potassium, calcium, magnesium, phosphorus
INCREASED = bacteria colony counts, somatic cell numbers, enzymes that destroy nutrients, pH, total whey, sodium, chloride, copper, iron, zinc
How can bacterial multiplication in milk be controlled in transport?
cooled immediately after milking and during transport
(below TDZ)
What exception is accepted to cooling milk directly after milking?
some processing steps of dairy products require a temperature above 4 C —> pasteurization and fermentation of cheese and yogurt
What kinds of bacteria are able to grow in refrigerated milk? What are the 7 most common species?
psychotrophs
- Pseudomonas
- Flavobacterium
- Alcaligenes
- Listeria monocytogenes
- Yersinia enterocolitica
- Bacillus
- some coliforms
What 4 tests must occur when milk shipments reach processing plants?
- temperature < 4 C
- pH 6.5-6.7
- organoleptic abnormalities: color (white), odor, taste (pleasantly sweet), consistency (liquid, but not watery)
- negative to drug residues by lateral flow assays testing for antibodies
