Test 2: Milk Processing

Pasteurization

Pasteurization

a process by which milk is heated to a specific temperature for a set period of time to kills harmful bacteria

Homogenization

Involves processing milk so that the cream does not separate

Clarification

Removes material such a sand, soil, dust, and precipitated protein

Standardization

Regulates the fat content of the milk

Milk Stone

Hard deposit of milk residues that adhere to milking systems

Direct loading of milk

Directly loading milk from the parlor to tanker truck

Bulk tank

Holds milks from parlor

Cryoscope

Detects freezing point by finding the amount of water added in milk

Psychrotrohpic bacteria

Bacteria that can grow at refrigeration temperature and spoil milk

Processed cheese

Cheese mixed with an emulsifying agent

Cold pack cheese

Created by blending natural cheeses without the use of heat

Cultured dairy products

Products that have been made by fermenting milk with lactic acid bacteria

What are the objectives of milk processing?

• make safe for human consumption

• Reduce spoilage

• Standardize quality and taste

• Convert to various products

Where does milk quality begin?

• at the farm

List the essentials of milk quality control.

• healthy cows, free of disease

• Clean cows

• Milking equipment

• Avoid off flavors and odors

• Rapid cooling

• Careful processing and packaging

List the steps required to property clean milking equipment after milking

• pre-rinse with clean, tepid (110-120F)

• Wash with chlorinated alkaline cleaner washing solution

• 160-170F at beginning of cycle

• At least 120F at end of cycle

• Acid rinse with tepid acidified water

List the steps required to property clean milking equipment prior to milking

• sanitize with an EPA registered dairy sanitizer solution

Under what circumstance would direct loading of milk be used on dairy farm instead of a bulk tank

If the farm is large they will more than likely use direct loading (750 cows)

How often is milk picked up from the farm

Usually every other day

What are the critical elements of managing a bulk tank?

• clean and sanitize after each pickup

• Filters-can b used to determine if we are doing a good job cleaning before milking

• Rapid cooling

• Proper agitation

• Temperature, odor check & sample at pick up

What does the pasteurized milk ordinance do? (PMO)

-They get standards for Grade A raw milk

-Establish guidelines for handling and production of milk and dairy products

What grade of milk does the PMO pertain to?

Grade A

Who writes the PMO?

National Conference on interstate Milk Shipments

Who enforces the PMO

Food and Drug Admin

State departments of agriculture

According to the PMO, what are grade A raw requirements for the following? Temperature

• less than or equal to 50 degrees F within 4 hours of commencement of first milking

• Less than or equal to 45 within 2 hours after completion

Bacterial Limits

Less than or equal to 100,000 colony forming units per ml

Antibiotic residues

No positive results

Somatic cell counts

Less than or equal to 750,000

What is the ideal temperature for storing milk?

Less than 45 ideally 40 degrees Fahrenheit

bulk tanks should be agitated before sample collection: how many minutes should it be agitated for bulk tanks containing 1000 gallons or less? And more than 1000 gallons?

5 for 1000 or less

10 for more than 1000

Why is there zero tolerance for antibiotics in milk

• some people are highly allergic

• Interference with milk processing

• Antibiotic resistance concerns

• Public perception

Why do we screen all bulk milk pick up tankers for beta-lactam residues?

Beta Lactam rings are found in the most common antibiotics used by farmers (penicillins and cephalosporins

Under what circumstances would a dairy farmer want to run an on farm antibiotic test on raw milk

• if you aren’t sure if a treated cows milk got put in the tank

• If you are using off or extra label antibiotics and if you wanted to see if antibiotics have left the animal systems

• Dry cow treatment

What are important considerations when purchasing an on farm antibiotic test?

• Cost

• Ease of use

• Accuracy

• Match the test to the drugs

What are the purpose and requirement for each of the following milk quality test: Rancidity

Detects flavor defect

What are the purpose and requirement for each of the following milk quality test: temperature

Makes sure the temperature is low enough to reduce bacteria growth

What are the purpose and requirement for each of the following milk quality test: standard plate count

Measures number of bacteria

What are the purpose and requirement for each of the following milk quality test: preliminary incubation count

Raw milk keeping quality measures psychotropic bacteria

What are the purpose and requirement for each of the following milk quality test: lab pasteurized count

Measures number of bacteria that survive lab pasteurization

What are the purpose and requirement for each of the following milk quality test: coliform count

Indicator of unsanitary production practices and or mastitis

What are the purpose and requirement for each of the following milk quality test: somatic cell count

Measure of udder health detect mastitis

What are the purpose and requirement for each of the following milk quality test: sediment

Measure of cleanliness

What are the purpose and requirement for each of the following milk quality test: freezing point

Detect added water

What is the purpose of the following ways that milk is processed and how is each process achieved: Clarification

Use of a centrifuge to get rid of sediment as it spins it will collect at the bottom

What is the purpose of the following ways that milk is processed and how is each process achieved: Separation

Separates cream from skim

What is the purpose of the following ways that milk is processed and how is each process achieved:Standardization

Puts the cream back together at the desired fat content

What is the purpose of the following ways that milk is processed and how is each process achieved: pasteurization

Heating of all milk particles for a certain amount of time at a certain temperature to kill bacteria

What is the purpose of the following ways that milk is processed and how is each process achieved: homogenization

Breaks down fat globules by passing milk under high pressure through a very small orifice, stabilizes fat emulsion in milk

What is the purpose of the following ways that milk is processed and how is each process achieved: Fortification

Addition of vitamins and minerals that are not naturally found in milk

What are the benefits of pasteurizing milk?

Health safety

Quality

What pathogens might be commonly found in raw milk?

• salmonella

• E.coli

• Listeria monocytogenes

• Coxiella brunetti

• Mycobacterium tuberculosis and paratuberculosis

How is batch pasteurization of milk most commonly used?

Agitator and heat

What are the advantages of batch pasteurization of milk

• good for small quantities

• Used for milk by-products like chocolate, yogurt, cheese

• Used mostly for production of ice cream mix

What are the disadvantages of batch pasteurization of milk

• should not be used or large quantities of milk

• Not energy efficient

• Time-long time to pasteurize

What time and temperature are used for batch pasteurization of milk

• 145 for 30 minutes

How is the continuous method of pasteurization of milk most commonly used

• flows through a series of plates

What are the advantages of the continuous method of pasteurizing milk

Energy and time saver because of heat plate exchangers

Used for pasteurizing large volumes of milk

What are the disadvantages of the continuous method of pasteurization

Should not be used for small quantities of milk

What is the time and temperature used for the continuous method

161 for 15 seconds

What are the two critical factors for effective pasteurization of milk

Heat and time

Is milk that is pasteurized using either batch or continuous sterile?

No

What are the advantages of UHT milk?

Only one that sterilized milk

High quality

Long shelf life

Packaging size

What are the disadvantages of UHT milk

Can give a cooked flavor to milk due to overheating

Hard to maintain sterile environment

Vitamins lost due to intense heating

What milk quality tests are performed after pasteurization

• Fat protein

• Standard plate count

• Coliform count

• E. coli count

• Yeast and mold count

• Phosphate test

What does a phosphatase tell a dairy plant manager?

If phosphatase is active it means the time or temperature factors were not right or it was contaminated by unpasteurized milk

What are the functions of packaging dairy foods

• efficient food distribution

• Maintain product hygiene

• Protect nutrients and flavor

• Reduce food spoilage and waste

• Increase food availability

• Convey product information

Differentiate the fat percent, calories, and grams of fat per serving between whole milk, reduced fat milk, low fat milk, and fat-free milk.

Whole milk- is 3.25% fat, 150 Calories and 8 grams of fat

Reduced Fat- is 2% fat, 120 calories and 5 grams of fat

Low Fat milk- is 1% fat 100 calories and 2.5 grams of fat

Nonfat- is 0% fat 80 calories and 0 grams of fat

Provide examples of specialty milk beverages

Lactose- reduced milk

Lactose free milk

Acidophilus milk

Milk enriched with plant sterols

Milk fortified with protein and calcium

How many pounds of whole milk does it take to make a pound of butter?

21.2

What is the minimum fat content of traditional butter?

80%

How many pounds of whole milk does it take to make a pound of cheese?

10

Cheeses are often classified according to moisture and softness or hardness. what are the four classifications, give examples of each

Very hard- Romano

Hard- Cheddar

Semisoft- blue

Soft- Brie

List thee exemplars of processed cheese

American Cheese, cheese spreads, cheese foods

What are the federal standards for the minimum fat and total milk solids in ice cream?

Greater than 10 percent fat

Greater than20 percent milk solids

Premium ice creams often contain heat percent milk fat?

60%

List three examples of cultured dairy products

Yogurt

Buttermilk

Sour Cream

List three examples of dry milk products

Dry whole Milk

Dried Whey

Dry Buttermilk

How is Greek yogurt different from Greek style yogurt?

Greek style yogurt includes thickening agents, whereas real Greek yogurt is strained though a cheese cloth