Milk quality Flashcards
List the milk producers of the world.
Which is the top producer?
India
What is the functional unit of the mammary gland ?
The alveolus of mammary gland (udder) is the
functional unit for milk production
Mammary gland is made up of two layers of cells
1. __________ are the milk producing cells
also called mammary ________ cells
They are located on the ________ inside mammary gland
2. _________ _________ cells
They are like ________ muscle
They are located surrounding _________
Mammary gland is made up of two layers of cells
1. lactocytes are the milk producing cells
also called mammary epithelial cells
They are located on the surface inside mammary gland
2. basal myoepithelium cells
They are like smooth muscle
They are located surrounding lactocytes
_________ L of blood comes to the mammary gland to produce 1 L of milk.
90,000
During lactation, or milking, when we touch the teat the animal feels that sense. __________ is released from pituitary gland –> _______ muscle of mammary gland –> squeezes ________ cells, each containing milk, which is then released.
During lactation, or milking, when we touch the teat the animal feels that sense. Oxytocin is released from pituitary gland –> smooth muscle of mammary gland –> squeezes epithelial cells, each containing milk, which is then released.
80% if milk is stored in ________, only 20% is stored just above the _____
80% if milk is stored in alveoli, only 20% is stored just above the teat
A cow has how many quarters?
4
Each quarter acts as?
an independent factory
There are more than ________ alveoli in each quarter that are arranged in the forms of lobules.
There are more than 200,000 alveoli in each quarter that are arranged in the forms of lobules.
Dairy cows starts production of colostrum nearly pre & post parturition for ___-___ days followed by milk production for ~___ days
3,5, 305
At ___ _____ of age is when a cow has her first offspring.
At 2 years of age is when a cow has her first offspring.
Colostrum is secreted within the first ___days, followed by regular milk for ___ months
Colostrum is secreted within the first 5 days, followed by regular milk for 10 months
Is colostrum milk?
No, it is highly concentrated dry matter composed of proteins including Ab and vitamins
Its water composition is very low, around 71%.
Milk is full of water (____%) followed by
- carbohydrate (_____%) > fat (____%) > protein (___%) > mineral &vitamins (____%)
Milk is full of water (87%) followed by
- carbohydrate (4.9%) > fat (3.4%) > protein (3.3%) > mineral &vitamins (1.4%)
The fat component of milk has more than 400 different fatty acids arranged in 3 broad categories. Polyunsat = omega fatty acids such as omega 3
Fat is really important in diet b/c we get cream, butter, ghee, and different levels of milk (%)
There are two types of proteins in milk
based on solubility in water
water soluble = whey
Nonsoluble: majority: 80% of proteins are insoluble. important for cheese industry (called casein proteins)
Vitamins in milk?
B12, B2, rich in Ca++ and Phosphorous
pH of milk ?
Naturally in pH danger zone
6.5-6.7
microorganisms love this environment
How do you know that milk is sanitary?
Measure cells: somatic cells and bacterial cells
What are the seven major parameters checked in raw milk production?
Regulated milk must have:
- 87% water,
- > 3.25% fat,
- > 8.25% non-fat solids
If do not have this? Adulterated/contaminated
llegal to sale milk with
SCC counts above the
set cu-off value by
federal regulators
> 750,000
Get prize for lowest somatic cell count
standard plate count of bacteria in milk must be < 100, 000 cfu/ml…… above this value is illegal to sale
Take 100 ml of milk, serially dilute in test tubes, swab 1 ml on agar plates, culture for 2 days at 32 degrees, count # of colonies that grew. This is used for regulating bacterial levels in milk.
Also check refrigerated milk bacteria too.
Do same thing as above by 12.8 degrees Celcius
Pasteurized milk - bacterial check
take sample of milk, heat it at 60 degrees, serially dilute in culture. if observe bacteria in culture = bad
How to check for fecal bacteria?
E.coli, enterobactera, citrobacter, etc.
Fecal bacteria that means the milk is contaminated with feces of animal
Swab milk on selective media, maconkey agar.
If find above certain limit they do not buy it.
Illegal to sale milk with SCC & SPC counts
above the set cu-off value by federal regulators
Organoleptic quality (Flavor, taste, appearance) of
milk must be:
1. Color: normal milk is whitish
2. Odor: should not have off-odor
3. Taste: normal milk is pleasantly sweet
4. Consistency: normal milk is liquid but not watery
If there is silage, it smells like silage.
There are 5 compounds in milk.
Water, Sugar (lactose), protein, fat, vitamins, minerals
If milk is contaminated with bacteria –> eat lactose –> lactic acid –> sour milk
Milk tastes cooked when?
It is too pasteurized
Milk becomes flat when?
They add water
Milk tastes rancid when?
Fat part of milk is converted by microorganisms
If pH changes from 6.5 or above and below this range, milk is?
Not normal
How do you grade milk?
Composition
somatic cell count
bacterial count
organoleptic
The following criteria are used in milk grading
1. Chemical constituents of milk – 87% water, > 3.25% fat, > 8.25% non-fat
2. Load of bacteria count in the milk
3. Bulk tank somatic cell count (udder health or mastitis)
4. Organoleptic features of milk – whitish color, pleasantly sweet and clean with no aftertaste
What are the grades of milk in the U.S.?
Three types of milk grades based on bacteria count in the milk
1. Certified milk: ≤ 10,000 cfu/ml bacteria
2. Grade A milk: ≤ 100,000 cfu/ml bacteria
3. Grade B milk: ≤ 500,000 cfu/ml bacteria
Certified milk is the best milk
Fecal bacteria is allowed in Grade A milk, e.g e.cli
Grade B is the lowest quality, up to 1 million somatic cell count and total bacteria count. we do not drink this milk, it is illegal
Grade A is used for cheese
Milk composition manipulation to form a new dairy product first by pasteurization
(heating) & cooling followed by separation, standardization or fermentation
What is are the four kinds of milk pasteurization?
pasteurization usd to be at 63
most common is high temperature short time at ? for 20 seconds.
make milk in can, canned serilization at 120 degrees celsius.
short ultra: only expose for 2 seconds; this is the most efficient one, gives shelf life of about half a year.
we can also
72 –> liquid
cheese and yogurt
What are the basic steps in milk processing is separating its components apart?
How do you sort milk components by nano-pore membrane technology?
NF = nanofiltration; scoop lactose and salt
1 = fat
10 um = proteins
1 um = lactose
How is milk processed?
How is cheese produced?
Heat up to 32 degrees
Add bacteria (Lactococcusl, striptococcus termophilis)
- Incubate with milk
Add renit (cuts caseins in milk) for 30 min
Increase temp to 38 max so it coagulates
remove liquid part once coagulated
knead the milk
add salt
cut ?
put in storage to make cheese; when ripened you can sell
By playing with water, you ma have?
hWhole milk
evaportated canned milk where remove60% water
Sweetended condensed milk with ?
Milk powder
Can play with fat cimponent to make cream, ice cream, butter, ghee (pure fat)
Which milk products are more susceptible to pathogens?
Cheese b/c it is a low quality milk used
- major pathogens: listeria monocytognees, e.coli, salmonella, fungus yeasts,
Milk is second
