Milk Hygiene Flashcards
8 step process from cow to consumer
- rearing
- harvesting (hand or machine milking)
- storing
- transportation (but first testing)
- lab testing - aroma, temp, pH, drug residue
- processing
- packaging
- selling
required hygienic practices
- animal hygiene
- milker’s hygiene
- utensils and equipment hygiene
- hygiene during milking process
- environmental hygiene
feed must be free from
- biological hazards
- chemical hazards
- physical hazards
what can minimize soiling and improve animal comfort
good bedding
water consumption per 1000 L of milk
1000-5000 per 1000 L of milk
water used to wash equipment and cow standings during and after milking
potable water
structures
- minimize risk of contamination
- floors impervious to water and free draining
- suitable draining system
- smooth doors and walls, impervious and easy to keep clean
- roof and loft floors made of dust proof sheet material and easy to clean
- ventilation - clean air and avoid condensation
- artificial lighting - shatterproof and waterproof, good visibility
sufficient potable water must be available in milking area for
- hand washing
- udder and teat washing
- rinsing and cleaning equipment
how often should inner surfaces of processing equipment and piping be cleaned
once a day
what should equipment and piping be made of
stainless steel
automated clean in place systems
- incorporated into equipment
- solvents run through the system and then flushed clean
sequence of utensils and equipment cleaning
- pre-rinsing
- alkaline cleaning
- rinsing
- disinfection
- rinsing
why is cleaning of teats before milking important
- remove visible soiling
- remove bacteria that may contaminate milk
what can reduce the count of bacteria in milk
clipping of hair around udder, flanks, tail
what is the link between udder and leg hygiene scores of lactating dairy cows vs mastitis
dirty body –> mastitis –> milk contamination (poor milk hygiene)
what is the critical control point (HACCP) in milk industry
milking step
what may be the singular most cause of milk contamination
mastitis
5D for milk hygiene
- distorted milk
- drug residues in milk
- devastated animal
- diseased
- discharges
what are some sources of contamination in milk after it leaves the udder
- bucket, pail, cans, bulk tanks
hygienic milking
- personnel and operator hygiene
- equipment cleaning
- milking environment
- teats, udder, and adjacent parts must be clean
what to do before milking to improve milk hygiene
- fore milking - check milk for physical, chemical, and organoleptic abnormalities
- odor, consistency, color of milk
- check udder for inflammation - swollen, hot, painful
what to do after milking to improve milk hygiene
- dipping teat in iodine
8 step by step milking procedure
- observation, sort 5D cows
- fore stripping, udder checking, sort 5D cows
- wash and dry teat and udder
- attaching milking unit
- adjusting milking unit
- end of milking - avoid overmilking
- milking unit removal
- disinfection
what is the most devastating problem to dairy industry
mastitis
environmental contributions to mastitis
- bedding, soil, fecal material
- E coli, Klebsiella pneumoniae, K oxytoca, Enterobacter aerogenes
contagious contributions to mastitis
- transmitted by contact, using the same machine without cleaning in between
- Mycoplasma bovis, Staph aureus, Strep agalactiae, Strep dysgalactiae
biggest indirect cost of mastitis
production loss
how much does the US lose annually due to mastitis
$2 billion
water microbes that can contaminate milk
coliforms
pseudomonas
coryneforms
alcaligenes
feed microbes that can contaminate milk
clostridium
listeria (found in silage)
bacillus
lactic acid bacteria
soil pathogens that can contaminate milk
clostridium
bacillus
pseudomonas
mycobacterium
yeasts and moulds
bedding microbes that can contaminate milk
clostridium
bacillus
klebsiella
milking machine microbes that can contaminate milk
micrococcus
streptococcus
bacillus
coliforms
outside udder and teats microbes that can contaminate milk
micrococcus
staphylococcus
enterococcus
bacillus
most important sources of milk contamination
milking machines and bulk tanks
why is mastitis one of the major factors that contribute to milk rejection
it destabilizes the udder ecosystem and milk composition
main changes in udder during mastitis
- leaking of ions, proteins, enzymes form blood into milk due to increased permeability (due to inflammation of mammary gland)
- invasion of phagocyting cells into milk compartment, basis for somatic cell counts (SCC) in milk to detect and monitor cows for milk hygiene
- decrease in synthetic capacity of gland, resulting in decreased concentration of certain milk constituents
- affected quarter may produce substances related to inflammatory reaction (acute phase proteins) released during stress
good components reduced by mastitis
- total casein (a and B fractions decrease, y fraction increases)
- lactose
- fat
- some whey proteins (a-lactalbumin, B-globulin)
- potassium
- minerals - Ca, Mg, P
bad components increased by mastitis
- bacteria colony counts
- somatic cell numbers per mL
- enzymes (destroy valuable nutrients in milk)
- pH
- total whey proteins (bovine serum albumin, immunoglobulins)
- sodium
- chloride
- ions - Cu, Fe, Zn
what aspect of milk does mastitis in lactating animals affect
- yield
- quality
- public health
what temperature must milk be cooled to and when
- 4 C
- immediately and across entire supply chain until consumption
exceptions to 4C temperature
- milk pasteurization or fermentation of cheese and yogurt require temperature higher than 4 C
what can grow in refrigerated milk storage (at 4C)
- psychrotrophs
- pseudomonas
- flavobacterium
- alcaligenes
- listeria monocytogenes
- yersinia enterocolitica
- some coliforms
- bacillus spp
what makes milk an excellent medium for microbial growth
- high water activity
- moderate pH (6.4-6.6)
- high nutrient content
on site milk testing to avoid contaminated milk shipment
- temperature of milk must be < 4C
- pH must be 6.5-6.7
- organoleptic abnormalities
- color - normal milk is whitish
- odor - should not have an off odor
- taste - normal milk is pleasantly sweet
- consistency - normal milk is liquid but not watery
- negative to drug residues by lateral flow assay
