ANSC 240 Exam 2

what is lactation

A distinguishing characteristic of mammals until it is weaned

what are the functions of the mammary glad

nutrition for offspring & passive immunity

human consumption of milk comes from what species

dairy cows, sheep & goats, water buffalo, yaks, camels, donkeys

Mammary gland in cattle

4 inguinal, most developed mammary glands, most knowledge

mammary gland in sheep/goats

2 inguinal, teats larger than cows, 2 or 3 young

mammary gland in horses

4 inguinal, 4 glands, but only 2 teats

what supports the mammary gland

the middle suspensory & lateral suspensory ligaments

what protects the mammary glands

skin

what is the functional unit of milk secretion

alveolus/alveoli

what is the secretory cells

epithelial

what is the contractile cell

myoepithelial

what is the milk collecting system

alveolar lumen, series of ducts, gland cistern, streak canal

what happens during prenatal gland growth

organogenesis; rudimentary glands are present at birth

what happens from birth to puberty of gland growth

little gland growth parallels body growth

what happens from puberty to conception of gland growth

duct system proliferation, little growth in gland size

what happens during pregnancy gland growth

substantial growth in gland size, proliferation in secretory tissue especially in late pregnancy

what are the major hormones

estrogen, progesterone, placental lactogen, prolactin, oxytocin

what does estrogen influence

duct growth & cistern growth

what does progesterone influence

alveoli growth

what does placental lactogen influence

general cell growth in mammary glands

what does prolactin influence

initiation of lactation

what does oxytocin influence

milk ejection reflex

What is the most abundant nutrient in lactose

carbohydrates

lactose=

milk sugar

what makes lactose

glucose + galactose

what enzyme breaks down lactose

lactase

which fat makes up most of the milk fat

triglycerides

can milk fat droplets pass through the cell membrane

no

what are the major proteins in milk

casein, alpha-lactalbumin, beta-lactoglobulin

is casein soluble or insoluble

insoluble

what are the primary minerals in milk

calcium, phosphorus, sodium, chlorine, magnesium

what vitamins pass from the blood to the milk

ADEK

what are some factors that affect milk secretion

inheritance, age, stage of lactation, persistency, estrus, frequency of milking, environment

list the order of milk production from highest to lowest by species

dairy cow, beef cow, sow, ewe, dairy goat, mare

what is colostrum

the first milk secretion from the mammary glands after giving birth, rich in antibodies.

colostrum milk is higher in what

dry matter, protein, vitamins, minerals

when should a newborn receive colostrum milk

within the first 24 hours

what can stress do to milk secreation

inhibit milk ejection reflex

what are some favorable stimuli for milk ejection reflex

nudging of the udder by offspring, washing the udder prior to milking, sound of the milking equipment or vocalization from offspring

what is bST

bovine somatotropin or growth hormone that increases milk production

order of milk let-down

favorable stimuli, sends message to the brain, oxytocin released, muscle contraction in the udder, milk let down

what is a colloidal

suspension of solids in liquid

SNF=

total solids minus milk fat

what goes into SNF

Protein, lactose, minerals

what is lactose in milk

predominant carb in milk

what is casein

protein found in milk

What is whey

protein that is apart of lactalbumin and lactoglobulin

What are immunoglobulins?

antibodies that Increase resistance to disease and infection

What vitamin is added to milk and why

vitamin D for calcium absorption

what are the characteristics of vitamins in milk

all essential vitamins found in milk, ADEK fat portion, water soluble nonfat portion

types of milk products in the U.S.

fluid milk & crème, cheese, yogurt, butter, ice cream, nonfat dry milk

Whole milk contains what percent milk fat and what percent SNF

>3.25% milk fat and >8.25% SNF

low fat milk contains what percent milk fat and what percent SNF

.5-2% fat and >8.25% SNF

Skim milk contains what percent milk fat and what percent SNF

what are some dairy products

evaporated milk, condensed milk, dry milk, sour cream, yogurt, buttermilk, cottage cheese, cream, butter, cheese

evaporated milk

Canned milk with 60% of the water removed, sealed and sterilized, >7.5% milk fat and >25% SNF

condensed milk

evaporated milk sealed in container and not sterilized

dry milk

95% water removed

what is cultured fermented dairy products

added bacteria to produced lactic acid

what is acidified fermented dairy products

+ or - bacteria to sour the milk or cream

sour cream

acidified, 18% milk life, shelf life 3-4 weeks

yogurt

cultured, heated before fermentation, fat depends of fluid milk used

buttermilk

Cultured,
Heated and cooled after fermentation

cottage cheese

cultured soft unripened cheese & mixed with pasteurized cream, >4% milk fat and

cream

fluid milk, >18% milk fat

what is 1/2 and 1/2 milk fat percent

10.5-18% milk fat

what is light cream milk fat percent

18-30%

what is heavy cream milk fat percent

>36%

Butter

>80% milk fat, use cream & separate out butter particles

What is quality control

numerous tests and samples conducted through all steps in milk processing gathered to analyze presence of microbiological organisms

SPC

Specific Plate Count

what is SPC used for

total number of bacteria and grading process

PMO

Pasteurized Milk Ordinance

Grade A Class 1

fluid milk

grade A class 2

cottage cheese, cream, frozen deserts

Grade B Class 3

butter & cheese

Grade A bacterial count

100,000 microbes before commingling, 300,000 after commingling

Grade B bacterial count

1,00,000 microbes before commingling, 3,000,000 after commingling

Grade A somatic cell count

Processing at dairy farm

milk taken from cow using sanitary milking machine, travels through pipes into holding tank, picked-up by tank truck & delivered to processing plant

what temp is milk at when received from the cow and when placed into holding tank

100, 40

what occurs during milk handling

within 72 hours of milk arrival it must be processed, tested for butterfat and SNF, tested for temp, acidity, flavor, odor, cleanliness, & absence of antibiotics

Processing at milk plant

kept in holding tanks, milk separation, pasteurized, pumped through series of pressurized valves to homogenize, cooled to

What occurs during milk seperation

whole milk separated into cream & skim milk

what is centrifugal seperation

cream moves towards center, skim milk moves outward

what percent of cream is BF

40

what percent of skim milk is BF

.03

what is standardization

remixing of cream & skim to reach desired specific designation, important to ensure every consumer gets milk with consistent fat content

what is pasteurization

heating a liquid to below the boiling point to destroy microorganisms

who developed pasteurization, when, & why

Louis Pasteur in 1864 to improve wine

when did commercial pasteurization of milk begin in Europe? US?

1800s, 1900s

What are the methods of pasteurization

HTST & UHT

HTST

high temperature short time

High temp short time pasteurization

161 F for 15 seconds, can be slightly altered for different products

UHT pasteurization

138C for 3 seconds

what is homogenization

reduces the milk fat globule size allowing for even distribution, prevents milk fat seperation

what vitamins are often fortified in milk

Vitamin A & D

what is shelf life

period of time products remain safe, retain desired sensory, chemical, physical & microbial characteristics, maintain labeled composition

shelf life of pasteurized milk

8-10 days at 5-7C, can be improved by combining pasteurization with bactofugation, microfiltration, or heat treatment

Differences between type of cheese

origin of the milk by breed, species or country, moisture content, specific mold & bacteria, length of aging