Transcript File

Fluid Milk
Developed by
Sheri L. Kahnke and Dr. Robert Baer
South Dakota State University
Modified by
Chuck Juntti and Kimberly Buehner
Davisco Foods International Unit of Agropur
What is milk?
 Milk contains:
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87.4% water
3.7% milk fat
3.4% protein (casein and whey)
4.8% (lactose)
0.7% minerals
What is milk?
 The acidity of milk as a quality parameter can be
expressed as Titratable Acidity
 Titratable Acidity is expressed as a % of lactic acid
 Fresh milk has a titratable acidity of around 0.20%.
 Titratable Acidity outside of this range can indicate
issues with:
 Very high bacteria counts in the milk
 Improper refrigeration at the farm or during
transporation
 Milk that is not fresh due to age
Fat
 Gives milk its desirable texture, appearance, and
flavor
 Suspended in milk as tiny globules held together in an
emulsion
 Unhomogenized milk will leave a layer of fat on top of
the milk
 2.4 billion fat globules/mL
The Complete Protein Package
 Milk proteins contain all essential
amino acids
 80% of milk proteins are casein
 Makes cheese
 Responsible for the whitish-blue color
tinge in skim milk
 The rest are whey proteins
 Used to be considered waste
 Now isolated, purified, and dried into
valuable protein powders found in
many Nutritional Shakes
Lactose Intolerance
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Milk sugar
Glucose + Galactose
Main carbohydrate in milk (ENERGY)
Lactose intolerance describes the inability to digest or
break down lactose
 Have the ability to filter lactose out of dairy products
 Used as a sweetener in milk chocolate and sweets
Minerals
 Major minerals
 Calcium
 Phosphorous
 Magnesium
 CALCIUM!!
 Good for strong healthy bones and
teeth
 Help prevent Osteoporosis
 Our bodies cannot produce calcium
 All sources of calcium must be absorbed
through food
Milk Categories
Skim (Nonfat) Milk
< 0.5% fat
Low Fat Milk
< 3.0% fat (usually 0.5%, 1.0%, 1.5%, 2.0%)
Whole Milk
≥ 3.25% fat
Flavored Milk
Made from skim, low fat, or whole milk
Vitamin A
 Vitamin A
 Must be added to skim and low
fat milks
 Optional in whole milk
 Added at 2,000 International
Units (IU)/quart
Vitamin D
 Optional addition to milk
 Added at 400 IU/quart
 Increases calcium absorption
into the body
 Rickets
 Bone softening disease in
children
 Vitamin D can prevent this
disease
Fluid Milk Processing
 Raw milk is pasteurized (heated) before being used
or consumed
 Exception: few cheeses use raw milk, but must be
aged > 60 days before being sold or eaten
 The sale of raw milk is prohibited in some states
 Controversial whether or not the sale of raw milk can
be prohibited
 Government is protecting consumers, because there
are pathogens in raw milk (Listeria, Salmonella, E.
coli)
 Consumers believe they have the right to purchase
raw milk as long as they know and understand the
risks
 What do you think???
Fluid Milk
 Milk is transported from farm to plant in tanker
trucks
 BEFORE milk can be unloaded tested for:
 Temperature < 45˚F
 Antibiotic Residues (Must be negative)
 Each tanker is also sampled individually
 Component Testing: proportion of fat/protein/lactose
in the milk
 Plants generally pay by the fat and protein %
 Also tested for somatic cell counts and other bacteria
 Other Titratable Acidity, pH, Sediments, Flavor
Milk Standardization
 Standardization: correct proportion of
fat/protein/lactose/total solids in the
milk
 Lowfat milk is processed through a
separator
 Spins the milk through discs at very high
speeds to ‘skim’ the fat (cream) from the
remaining milk
 Whole milk will occasionally need more
fat or cream
Pasteurization
 Developed by Louis Pasteur in 1864 to improve the
shelf-life of wine
 Heat treatment to increase shelf-life and kill
pathogenic (harmful) bacteria
 1947 Michigan became the first state to require milk
to be pasteurized
 The minimum temperature for heat treatment is set
from Coxiella burnetii
 Currently the most heat resistant pathogen
 Dairy industry is considered safe and accounts for less
than 1% of the food-borne outbreaks
Pasteurization
 Requirements for pasteurization are regulated by the
Pasteurized Milk Ordinance (PMO) of the Federal
Government
 It requires that every particle of milk be heated to a
specified temperature for a specified time
 These requirements are closely monitored by each
state’s Dept. of Ag
Pasteurization
 3 types of Pasteurization:
1.
Batch: heated to 145 ˚F for 30 min, then cooled to 45
˚F within 2 hours
2. High Temp. Short Time (HTST): heated to >161˚F for 15
sec, then cooled to 45 ˚F
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Most Common in the U.S.
3. Ultra High Temp (UHT): heated to >280 ˚F for 2 sec,
then cooled to 45 ˚F
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Common in Europe, used in coffee creamers, and softserve ice creams
Pasteurization
 Alkaline Phosphatase is the most heat stable
bacterium found in milk.
 Proper pasteurization will deactivate the phosphatase
enzyme in milk.
 Denatured phosphatase indicates that all other
harmful bacteria have been killed as well.
 Testing for this enzyme may be completed as a
verification that pasteurization has occurred.
Homogenization
 Pasteurized milk is pumped through a
homogenizing valve
 Smashes large fat globules into smaller
pieces
 Evenly distributes the particles in the
milk
 Keeps fat from separating from the
milk
 Must be done after pasteurization
otherwise the milk will become rancid
from the fat becoming disturbed
Standardization of Milk
 Raw milk generally has ~ 3.7% fat
 Jersey cows tend to produce higher fat levels
 Fat/protein levels will fluctuate depending on the
season
 During very hot weather will decrease
 Very few dairy products require exactly 3.7% fat
 Have to calculate the desired levels of fat/protein
 Pearson Square is a common tool to assist
Pearson Square
1. Draw a square
2. Put the desired fat % in the
middle (20%)
3. Put the % fat in milk and cream
that you have on the left side
4. Subtract diagonally to find the
correct ratio of ingredients
that are required
4% milk
4 parts milk
20%
24% cream
16 parts cream
Pearson Square
 Add the total parts
 Need 200 lb of 20% cream:
 200lb / 20 parts = 10
 Cream:
4% milk
 10 x 4 = 40 lb milk
 Will need 160 lb of cream and
40 lb of milk for 200 lb of 20%
cream
20 total parts
20%
24% cream
16 parts cream
4% milk
 10 x 16 = 160 lb cream
 Milk:
4 parts milk
4 parts milk
20%
24% cream
20 total parts
16 parts cream
4% milk
4 parts milk
20 total parts
20%
24% cream
16 parts cream
Milk is something to sing about!
 http://www.ispot.tv/ad/7Yz6/real-california-milkshower-singer
 California Milk Advisory Board 'Shower'.mp4