Benefits and Values

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1.  What is the nutritional value of milk?

2.  Going beyond the Nutrition Label — What other nutritional values should we be considering?

3. What are the additional benefits of milk fresh from the cow?

4. What is the impact of pasteurization on FUW milk’s value?

5. What is the impact of homogenization on FUW milk’s value?

6a.  Assuming that all milk is not the same, what do production and management practice have to do with FUW milk’s nutritional value, pathogens, color, taste, etc.?

6b. What is the impact of consumer preferences on production and management practices of FUM?

Discussion Summary:

1.  What is the nutritional value of milk?

Milk is a complete food.  It serves as the sole nourishment and fluid for newborns during a most critical stage of their development. It is an important part of most children’s diet, with dairy products providing calcium and many other nutrients needed for a growing child.  For adults, milk is a readily available source of numerous essential nutrients including high-quality, low-cost protein, a minimum of carbohydrate and an appropriate balance of fatty acids. Milk is considered an excellent source of calcium, phosphorous, vitamins B₂ and D and a good source of fat, carbohydrate, protein, vitamins A and B₁₂.  It is considered a poor source of iron, fiber, vitamin C and the B vitamin, folate.

The taste of milk is generally enjoyable, and this pleasure enhances its digestibility.

Nutrition fact labels list the quantities of certain nutrients in food. The amount of a nutrient is listed as a measured weight, such as in grams (g) or milligrams (mg) or International Units (IU). The other way of indicating proportion is to list a compound using A complicated formula which is based on an estimated intake from a 2,000 or 2,500 calorie diet is indicated as a a Percent Daily Value number (%DV). The energy we derive from food is measured in calories and is listed for fat, carbohydrates, and protein on the label. The calorie number is based on the serving size, listed at the top of the label, multiplied by the calories per gram: Fat - 9 calories/gram, Carbohydrate - 4 calories/gram, and Protein - 4 calories/gram.

Label for Organic Whole Milk

FATS

Fats consist of a large group of compounds that are made up of fatty acids (saturated and unsaturated).  Fats are generally soluble in organic solvents and largely insoluble in water. Fats support and cushion organs and protect nerves. Nutritionally, fats are the source of essential fatty acids. In nutritional terms, an essential substance is one that cannot be produced by the body so it must come from the food we eat. Non-essential substances can be synthesized internally. The fat-soluble vitamins A, E, D and K can only be digested, absorbed and transported in association with fats, and the body can store these vitamins in fatty tissue.  Milk fat in dairy products is the carrier of these fat-soluble vitamins, as well as important flavor and aroma substances.

The fat content of commercial milk is typically standardized at: ½%, 1%, 2%, or 3.25%.  See representative labels below.

CARBOHYDRATES

Carbohydrates are organic compounds that include sugars, starches, cellulose, and gums.  They serve as a major energy source.  The main carbohydrate in milk is the sugar lactose.

PROTEIN

Proteins are large organic compounds composed of amino acid chains.  Proteins are utilized in every physiological process within the body.  Milk is a complete protein-- it contains all eight essential amino acids and some that are non-essential.  The most plentiful protein in milk is casein. Casein proteins are unique to milk and milk products, they are not found in any other foods. 

VITAMINS and MINERALS

Vitamins are organic substances required for many physiological processes. Milk contains fat-soluble vitamins A, D, E, and K. Vitamins A and D work as a team, so both must be available in the proper proportion and at the same time to be assimilated. Milk is also an important source of several water-soluble vitamins: B₁ (thiamine), B₂ (riboflavin), B₃ (niacin), B₆ (pyridoxine), B₁₂, niacin and pantothenic acid.

All 22 minerals considered to be essential to the human diet are present in milk. Milk supplies these minerals in the correct proportions. Calcium, magnesium, and potassium are needed together for healthy bones. They also serve to regulate nerve connectivity and muscle and nerve contractions. Appropriate balances of these minerals prevent misfiring and cramping of muscles, including the muscles of the heart. Sodium, potassium, and chloride serve to maintain the osmotic equilibrium of milk with blood.

There is very little difference in the calcium content of reduced-fat dairy products compared to those made with whole milk.

See References for this question.

2. Going beyond the Nutrition Label — What other nutritional values should we be considering?

In addition to what is listed on conventional nutrition labels, we find that milk is complex and contains other required, interdependent elements such as enzymes, vitamins, and minerals.  Many of these elements are absorbed intact and function directly in our metabolism.  Others serve to foster the bioavailability of the basic nutrients— fats, carbohydrates, and proteins, in the milk. 

FATS

The fat in whole milk has many benefits.  Butterfat is the natural fat of milk.  It is the chief component of butter.  Historically, it is one of the first fats from animal sources to be used as a food.  Butterfat is good for the bones and enhances the immune system. It is directly absorbed, thus giving quick energy instead of being laid down as body fat for future utilization.  In addition, fat in the diet gives an increased satiety value by slowing absorption of the food eaten.  The slow digestion of fat provides gradual energy and allows the body to absorb needed nutrients along with the fat.  The good satiety of whole milk may contribute to eating appropriate amounts of food, i.e., not overeating.

Each butterfat globule is surrounded by a membrane consisting of phospholipids and proteins. These emulsifiers keep the individual globules of butterfat from joining together into clumps and also protect the globules from the fat-digesting activity of enzymes found in the fluid portion of milk.
           
In addition to the conventionally listed fats, Omega 3 and Omega 6 fatty acids occur in whole milk. 

The scientific community is looking closely at Conjugated Linolenic Acid (CLA).  CLA is a unique fatty acid that is formed in the rumen, the first chamber of the cow and sheep’s digestive system that allows them, by bacterial action, to utilize fresh grass as their primary food.  The amount of CLA in milk depends on the breed of the animal, its feed and environment, and the seasons.  Researchers are excited by the possibility of CLA being effective in cancer prevention, particularly in breast and prostate.   Research is suggestive that CLA may strengthen the immune system, and it may also have properties that tend to normalize body fat deposition. 

The fat in whole milk contributes 48–50% of the calories and most of the flavor of milk.

“There is no evidence that moderate intake of milk fat gives increased risk of diseases.” - Anna Haug, et al  “Bovine milk in human nutrition – a review”

CARBOHYDRATES

Milk has a glycemic index number of 30.  Foods with a number below 55 are considered ‘low’ and are therefore good choices for a sugar-restricted diet, such as diabetes.  Another plus is that eight ounces of milk contains twelve grams of sugar, a commonly recommended target amount for a snack. 

PROTEINS

“The protein in milk has a quality higher than many other foods but the quantity of milk protein is low due to high water content.  Milk protein contains all the essential amino acids required by the body for optimum growth, for this reason more of the protein can be used for protein anabolism so there’s less chance the protein in milk will be converted to fat and stored.”  – American Dairy Science Association, 1999  

The protein casein represents about 80% of milk protein.  Caseins are a large group of related proteins that are bound together with calcium phosphate into aggregates known as micelles (pronounced MY cells).  Micelles contain a mixture of the various caseins, as well as the calcium, magnesium, and inorganic phosphorus needed to build bone, muscle, and tissue.  The structure and composition of micelles make the casein proteins and the salts of the minerals calcium (Ca), magnesium (Mg) and inorganic Phosphorus (P) more bioavailable. They also form a curd (clabber) in the stomach for slower, more efficient digestion.

There are dozens of other proteins in milk that are more water-soluble than caseins.  Because these other proteins remain suspended in the whey left behind when the caseins coagulate into curds, as in cheese making, they are collectively known as whey proteins. Whey protein is absorbed rapidly, resulting in high concentrations of amino acids in the blood stream for ready energy and muscle strength. Excess calories from carbohydrates and protein, not just fat, are made into fat by the liver and adipose tissue.  By the same token, high quality protein, appropriate amounts of carbohydrates and good fat, all contribute to the satisfied feelings of a meal. 

OTHER NUTRIENTS

Enzymes act as catalysts, contributing to nutrient availability (bioavailability). In whole or complete foods such as milk, the enzymes that are needed to digest a compound usually occur along with the compound. For example, lipids need lipases, and proteins need proteases. These and other enzymes are present in milk as it comes from the animal. Lactose needs lactase to make it available. Lactase is not in the milk. It is produced and utilized in the intestines by the action of bacteria, e.g., lactobacilli, lactococci, and lactobifidia. These beneficial bacteria are present in abundance in fresh unprocessed milk. Enzyme activity is generally maximized at body temperature.

Vitamins help control the metabolic processes.  Milk provides many vitamins.  Vitamins A and D are fat-soluble vitamins that work synergistically.  Both are necessary for each to fulfill its nutritional tasks.  They occur naturally together in milk. Vitamin D, essential for bone health, is associated with suppression of osteoporosis. Vitamin A is critical for immune function and the health of the eyes.  Vitamin B₁₂ is found in animal foods.  There is a significant amount of vitamin B₁₂ in milk.  It plays a key role in folate metabolism, which prevents spina bifida in the developing fetus.  B vitamins, especially niacin, are important for the normal functioning of many enzymes in the body and are involved in the metabolism of sugars and fatty acids.

Antioxidants can slow or even prevent cellular damage.  Vitamins A & E and the mineral selenium are antioxidants that are present in milk in sufficient amounts to function appropriately.   Selenium aids the body in manufacturing C0Q₁₀, an enzyme that is specific for heart muscle health.  Vitamin K₂ (menaquione) is the form of the K vitamin found in milk.  Mammals make K₂ from K₁ which is found in plants (phyloquinone) and it is also made by the bacteria that line the human gastrointestinal tract.  Some studies indicate that Vitamin K helps in maintaining strong bones in the elderly.  Calcium cannot be assimilated without vitamin K. Vitamin K also plays an important role in blood clotting.

Whole milk has a balance of nutrients that are provided in a convenient form that is adaptable to many uses, and for most people, pleasant to our taste.  The nutritional value of milk is optimized by using whole, full-fat milk. 

See References for this question.

3. What are the additional benefits of milk fresh from the cow?

Milk fresh from the cow is a complete, living, functional food.  Although we have looked at the numerous nutritional components of milk in the previous two questions, the full benefits of milk are only realized when all of these components function as a complex interdependent and balanced process.  Included here are components that are not nutrients, although some do contribute to nutritional processes indirectly.

These components include:

1. ENZYMES

Enzymes are specialized proteins produced in cells that link, break-up, or accelerate chemical reactions.  They are considered catalysts because they are not consumed during the processes they control.

Intrinsic (Indigenous) Enzymes
There are many enzymes that exist naturally in fresh milk, these are called intrinsic enzymes.  Some intrinsic enzymes actively participate in the breakdown of components of milk, others breakdown the products of other enzymatic activity, still others have antimicrobial, and/or antiviral activity.  As an example, milk, as a complete and adequate food for the newborn calf, contains nearly all of the necessary enzymes to make milk bioavailable. Some enzymes in the newborn calf’s digestive tract are also active in making the components of milk bioavailable.  The entire process is complex and designed to function as an integrated system.  It is this integrated system that is so important to the newborn calf during the rapid, crucial, and elaborate development that occurs in the weeks after birth.  During this time the newborn’s only intake is milk, providing the adequate amount of water, and supplemented with air.

A partial list of well-characterized intrinsic enzymes contained naturally in fresh milk includes:

Acid Phosphatase Alkaline Phosphatases β-N-acetylglucosaminidase Esterases γ-Glutamyl transferase Lipoprotein Lipase Lysozymes Proteinases, including plasmin and cathepsin Superoxide dismutase Xanthine oxidase

Aldolase Amylase Catalase Glucose oxidase Glutathione peroxidase Lactoperoxidase Phospholipase Ribonuclease Sulphydryl oxidase Xanthine oxidoreductase

The enzymes found in milk can be large and complex such as catalase below:

Others like the lysozymes are small and simple:

*3D images are from the International Protein Database

Extrinsic Enzymes
Extrinsic Enzymes are enzymes that are made by microorganisms in milk, not produced by the mammary glands.  These enzymes may be active in the milk or within the microorganisms themselves.

There are many such enzymes and they are very complex.  Some of the specific enzymes are similar to those in the list of intrinsic enzymes.  These enzymes are variable depending on which specific bacteria are present in the milk.  For the most part these enzymes participate in the breakdown of milk components to enable utilization by the microorganisms, but they also participate in the processes of bioavailability in the intestinal tract.            

Because this list of enzymes is so variable and extensive, it is not practical to list them here.           

2. IMMUNE SYSTEM ENHANCERS            

• Activation and enhancement of the innate immune system in newborns; these are nonspecific mechanisms that resist pathogens and toxins by interfering with their ability to cause infection.
           
• Triggering cell-mediated immune mechanisms; this system works by activating specific-response white blood cells to attack new and recurrent exposure to pathogens.
           
• Stimulation of specific immune reactions; this mechanism reacts in response to antigens by producing antibodies.
           
• Other specific immune active components; Compliment, Immunoglobulins (IgM, IgA, IgG) and Gamma Interferon
           

3. CELLULAR ELEMENTS

Bovine phagocytes and white blood cells in milk continue to be active within the digestive tract until they die, within days or weeks. 

Many of the cellular elements measured in the Somatic Cell Count test of healthy cows are exfoliated lining cells that release lysozymes when they are killed in the gastrointestinal tract as a part of the normal digestive process.  These lysozymes nonspecifically attack microorganisms.

4. ADDITIONAL ANTIBACTERIAL COMPONENTS

Digestion produces free fatty acids with bactericidal (kills bacteria) effects (medium- and short-chain fatty acids).

• Bacteriocins- Nisin, colicins, etc. are produced by beneficial microorganisms. There is a growing list of bacteriocins; compounds with bactericidal or bacteriostatic (inhibits bacteria) activity produced by bacteria commonly found in fresh milk.  Bacteriocins can be extremely specific or more general in their attack on other microorganisms.
• Mucins- Some pathogens rely on their ability to adhere to the intestinal cells in order to cause illness.  Mucins are glycoproteins normally present on mucosal surfaces, including the intestines.  The most studied mucin in milk is MUCI, which has been shown to adhere to bacteria and interfere with their ability to adhere to intestinal cells.
• Microorganisms that suppress pathogens by competitive mechanisms-
  • Compete for nutrients
  • Compete for intestinal attachment sites necessary for some pathogens to produce illness
  • Compete by limiting colonization of less robust microorganisms (this is also called competitive inhibition), such as pathogens.
• Lactoferrin-(iron binding glycoprotein that scavengers iron from the environment) - It has well documented bacteriostatic and bactericidal activity.
• Lactoperoxidase system- The system consists of the enzyme lacctoperoxidase with cofactors, thiocyanate and hydrogen peroxide. The complete functional system is naturally present in fresh milk. This is a potent antimicrobial system approved internationally to preserve milk in locations where refrigeration is not practical by adding more of the two cofactors.
• Lysozymes- Different forms of this enzyme are present in all cells, in a sequestered location.  When cells are damaged, their store of lysozymes is released.  Lysozymes have broad and effective antibacterial activity. Lysozymes are present in free form in fresh milk and are also released from the breakdown of bovine cells present in the milk.
• Xanthine oxidoreductase- Besides its role in nutrition, this enzyme augments intestinal defenses against pathogens by producing several reactive byproducts.

5. BENEFICIAL MICROORGANISMS-
There are large numbers of different bacteria present in fresh milk. Some of these are included in the Standard Plate Count test; others do not grow under those culture conditions and so are not counted as a part of the test.  Both the total numbers and the diversity of bacterial types (genus and species) are variable.  Most of these bacteria are beneficial.  (Some people would characterize these as probiotics; however, in the ever-evolving definition of probiotics, this term is currently confined to products in which beneficial microorganisms are added.  Therefore, we will describe them as beneficial bacteria.)  As mentioned above some of these beneficial bacteria have mechanisms for suppressing pathogens.  A few of the best known beneficial bacteria in fresh milk   include:

• E. coli (the vast majority of E. coli is beneficial and naturally formed in our large intestines; the 0157:H7 sub-type is one of the rare exceptions)
• Lactococci
• Lactobacilli  
• Bifidobacteria

There are numerous other, mostly anaerobic microorganisms, i.e., microorganisms that live without oxygen, that participate in the digestion of food and the assimilation of nutrients.  Nearly all of these organisms enter milk from colonies that become established in the distal portions of the mammary gland passageways.  It is probable that the specific genus and species vary between different cows, over time, and depending on the environment.

6. FOLATE BINDING PROTEIN-
Protein that assists in the uptake of Folate in the intestine.

7. VITAMIN-COFACTORS, PROMOTERS OR ENABLERS-
Some of the trace elements present in milk are essential to vitamin activity, such as carotenes.
           
8. PREBIOTICS-
Unlike probiotics, prebiotics are recognized as anything that promotes the growth and
activity of beneficial microorganisms.  Therefore, milk is inherently a prebiotic since it contains lactose and numerous other components that beneficial bacteria can utilize.  One specific prebiotic factor present in fresh milk is lactoferrin, which interestingly is well known as an antibacterial agent, but it also promotes the growth of bifidobacteria.

9. HORMONES-
These are nearly all specifically bovine hormones, but there is evidence that they exert some influence prior to their inactivation.  The amount of each of these hormones tends to vary during the normal reproductive cycling of the cow, as well as by the seasons of the year.  The more common hormones include:

• Bovine growth hormone
• Bovine estrogens
• Bovine calcitonin
• Insulin-like growth factor-1 (IGF-1)
• Bovine prolactin
• Bovine thyroid stimulating hormone

10. VITAMIN B₁₂-
There is a significant amount of vitamin B₁₂ in fresh milk.  This vitamin is not present in plant foods and is a key to Folate metabolism.
 
11. TRACE MINERALS-
Specific trace elements are necessary as cofactors for many critical enzymes. The presence and   amount of trace minerals is a function of dietary intake of the milk-producing animal.  Essential trace minerals in milk include:
Iron, copper, zinc, manganese, cobalt, iodine, chromium, selenium, and molybdenum. 

12. OTHERS-
Freshness- Freshness provides enhanced ability to produce products from milk such as:

• Cream, Butter, Ghee (Indian clarified butter)
• Curds & Whey products, e.g., soft cheeses
• Cultured products such as cheeses, kefir, yogurt, cultured butter and crème fraîche, etc.
  • Some of these rely on microorganisms and communities of microorganisms present in fresh milk that participate in the natural culturing of milk under controlled conditions.
  • Others are produced by using starters, such as for specific cheeses.  These starters work best in milk that is less than two days old.
• Taste- Taste is rated high on beneficial values of fresh milk.  It is naturally variable, mostly a function of feed, including types of forage, other added foods, and the animal breed.  Seasonal variation is particularly noticeable.  Geographic location is often responsible for specific, much sought-after tastes.
• Viscosity/Body- Important beneficial value, influenced by the fat content, aggregation of fats and the interactions of proteins.
• Color- Variable depending on the fat content and the nature of forage, particularly on the amount of fresh, rapidly growing grasses.
• Lactoferrin- Included above as an antibacterial property.  Its ability to accumulate bioavailable iron is also a benefit.
• Overcoming the symptoms of lactose intolerance- Many people with professionally diagnosed lactose intolerance do not have the symptoms of this condition, even when consuming large amounts of fresh milk.
• Enhancement of mother’s breast milk quality by including fresh milk in her diet.
• Fibrinolysis system components- Particularly important in the newborn whose systems for combating inappropriate clotting have not developed fully.
• Reduction in asthma and allergic rhinitis-  Numerous well-controlled studies have shown the independent effect of drinking fresh milk on reducing asthma and childhood rhinitis in general and specifically in childhood allergic rhinitis.
• Beneficial in some autistic children
• Anti-stiffness/Anti-arthritis factor- Wurzen factor found in butter fat.
• Risk Reduction of Metabolic Syndrome- Increasing the consumption of milk and other dairy products may reduce metabolic syndrome (MetS) – report states that drinking a pint of milk daily was associated with a 62% reduction of risk for MetS.
• Medical treatments using fresh milk- The “Raw milk diet” has a 150-year history. It was used in the Mayo Clinic and by others and is currently practiced in Europe.
• Functional Medicine- the increasing use of prebiotics, probiotics and fresh milk to treat a variety of intestinal disorders.
• Intact milk fat globules are surrounded by a lipoprotein membrane.  This membrane maintains the globule, resists metabolism and contains some of the enzymes and beneficial factors listed above

See References for this question.

4. What is the impact of pasteurization on FUW milk’s value?
(Refer to Topic 2: Question 1, Question 2, and Question 3)

Pasteurization is defined in the 2007 Grade “A” Pasteurized Milk Ordinance (PMO) as follows:
The terms “pasteurization”, “pasteurized” and similar terms shall mean the process of heating every particle of milk or milk product, in properly designed and oper­ated equip­ment, to one (1) of the temperatures given in the following chart and held continuously at or above that temperature for at least the corresponding specified time:

The term “Ultra-Pasteurization”, when used to describe a dairy product means that such product shall have been thermally processed at or above 138ºC (280ºF) for at least two (2) seconds, either before or after packaging, so as to produce a product, which has an extended shelf-life under refrigerated conditions.  (Refer to 21CFR 131.3)

In addition to these time and temperature requirements for heating milk and milk products, the PMO requires that the equipment used to pasteurize and ultrapasteurize milk be properly designed, operated and tested.  These requirements are specified in PMO Item 16p, Appendix H and Appendix I.

All effects of pasteurization are variable dependent on temperature and time. There are many standards for pasteurization depending on the product being produced and the intended qualities of the end product. Also, the components of milk differ greatly, and making different dairy products requires different levels of heat treatment and protein denaturization.

Proteins
Proteins are incrementally denatured by heat. With lower heat treatment levels, complex proteins with three-dimensional configuration are altered. With higher heat treatment levels, the primary shape and bonds are altered. At very high heat levels, there are destructive chemical changes.

The casein proteins themselves have been shown to be relatively heat stable. However, the actual bioavailability of the casein proteins is far more complicated. There are a large number of different casein proteins (as many as 1,000). These are “packaged” in the large and complex physical structure, the micelle. Individual micelles contain a variable mixture of these different caseins. The micelle functions as a reservoir of nutritionally important proteins, and all of the essential amino acids that combine to make up the different caseins, in a structure that is critical in the physical properties of milk, altering the enzymatic digestion of the proteins and affecting the movement through the intestine. The food industry is well aware that casein micelles are altered within the range of pasteurization time and temperatures such that they alter the way milk behaves when used to produce a variety of dairy products. Furthermore, the micelles contain both calcium and phosphorus, internalized in association with the proteins in specific concentrations and in physical forms that facilitate availability during digestion. It is well recognized that heating milk in the range of pasteurization alters the physical properties of the micelles. With heating, the whey proteins become bound to the micelles.

Whey proteins denature more readily, particularly the immunoglobulins.

Carbohydrates
Lactose does undergo the Maillard reaction, the chemical binding of sugar to protein also commonly called the browning effect, which is progressive as temperature is increased. This affects color and taste.

Fats
This is complex because changes to the fat globules, specifically the membranes, are caused by both heat and homogenization. Of all the milk constituents, the milk fat globule is the most drastically altered by the combination of pasteurization and homogenization.

Minerals
The minerals themselves are not affected by heat. However, what they are bound to is. For example, calcium and phosphorus are contained within the structure of the micelles, and thus, their intestinal absorption is affected by the heat treatment level.

See References for this question.

 

5. What is the impact of homogenization on FUW milk’s value?

The purpose of homogenization is to decrease the size of the fat globules to prevent a creamline and create a more uniform product. Fat globules are decreased by mechanical disruption.

Homogenization became standard practice because it made fluid milk easier to standardize and removed the creamline as a marketing property. In practice, homogenization is not performed without pasteurization because homogenized milk becomes rancid rapidly.

Homogenization is a physical action that substantially reduces the size of the milk fat globules. In the process, the complex lipoprotein membrane that surrounds the native fat globules is disrupted. This membrane is biologically active, containing many enzymes and a variety of active protein and mucin molecules. One of the critical functions of the membrane is to protect the internal fats from premature digestion. The smaller globules become enveloped by other proteins because the surface area is considerably increased as the globules are reduced in size, and there is not enough of the fragmented native membrane to complete the coating. The substituted proteins (mostly caseins) are not as effective in protecting the contained fats.

See References for this question.

 

6a.  Assuming that all milk is not the same, what do production and management practice have to do with FUW milk’s nutritional value, pathogens, color, taste, etc.?

Healthy cows provide quality milk.

1. Pasture-based production practices
   There is evidence that properly managed pasture-based production practices improve the quality of milk.  For example, cows that are pasture-based on primarily mixed grasses produce milk that is higher in CLA, beta-carotene, and fatty acids. A diverse grass/clover mix is best, and it does make a difference what types of grass mixes are used and how the pasture is managed.  When cows are not on pasture, the fatty acids and vitamins in the milk decrease.  A mixture of hay and fibrous grains are good winter feed for animals that are otherwise pastured. Whereas younger grasses have a higher protein content and produce more CLAs, more mature grasses provide more minerals important to reproductive health.  A rule of thumb for animals in Michigan is one cow per acre of pasture.  Thus, pastures must be managed carefully and actively, and with an eye to long term sustainability to produce high quality milk.
   
   
2. Feeds and grains
   The content of feed, and changes in feeding, affect taste and color of milk. Proper management of fermented feeds reduces animal health risks. 
   
   
3. Soil Quality
   Soil and manure management practices have an effect on nutrient availability in soils, which, in turn, has an effect on the nutrient composition of grasses and other feeds.  This affects the nutritional quality of milk such as CLA, beta-carotene, and fatty acids. Additionally, the way soil and manure are managed has an effect on plant composition, soil microflora and the presence of plant disease-causing organisms in the soil. All of which affect the nutrient value of the feed that the cows consume, and hence, the health of the cows. 
   
   Organic matter with appropriate humus content is an essential component of a healthy soil system. Building the system depends on the quality of the humus in the soil and the practices of application of manure or other organic matter sources over time.  Decomposition in these systems relies on aerobic activity, which converts organic matter into humus.  Soils that are building organic matter tend to have more beneficial organisms, which help build beneficial soil microflora. 
   
   While anaerobic liquid manure systems are prevalent on dairy farms in Michigan, aerobic systems appear to produce manure that is more complimentary to soil quality.  
   Key nutrients such as nitrogen (N) and potassium (K), are more easily managed in aerobic and grazing systems.  These nutrients must be managed via application rates; too much of these two nutrients will cause an overfeeding of the plants, and thus disrupting plant metabolism and hence, the nutritional value to the cows. 

Variation is part of the value of FUW milk.

The taste/flavor and color of milk naturally varies according to breed of animal and what they are fed.  These variations can be affected by farm management practices, which consumers of FUW milk accept and appreciate.

• Whole milk has higher butterfat content. Fat plays the primary role in carrying flavors of milk.  A satisfying and pleasant richness is a characteristic of FUW milk.  The more frequently a cow is milked, the lower the fat content per milking.
• Temporary variations in the taste of milk can also occur with a change of seasons and feeding patterns.  There can be incidental unpleasant tastes resulting when a cow eats certain weeds (e.g. wild mustard garlic and wild onions) just before milking or when she is sick or in the very late part of her lactation cycle. Odors in cow housing and milking environments can cause off-flavors in the milk.
• The color of the milk changes noticeably in the spring when cows are primarily eating green growing grass, and becomes cream-colored because of the increased levels of beta carotene in the butterfat. 

6b. What is the impact of consumer preferences on production and management practices of FUM?

In a system in which consumers interact directly with the dairy farmer, some farm management choices are influenced by special consumer demands. There is no defined set of standards, however, based on discussions with Michigan consumers and farmers providing FUM done by the MI Fresh Milk Council, there are some common preferences:

• They want the way the farm is managed to be dedicated to production of milk intended to be consumed without processing, and farmers that welcome inspection of their operations.
• They want the cows to have free access to pasture, not raised and maintained in confinement.
• They want the cows fed forage, preferably pastured on grasses. 
• They want the milk to be in a fresh natural state without processing e.g. unpasteurized, not homogenized, and with nothing removed and nothing added.
• They expect high butterfat content. 
• They want the animals to be well cared for. 
• They specifically do not want feed that includes genetically engineered crop products, any soy, or by-products like brewer grain, beet pulp, or cotton seed.
• They do not want any pharmaceuticals used to enhance milk production. 
• They prefer no use on the farm of chemical fertilizers, herbicides or pesticides.
• They are willing to pay for quality.
• They are willing to go out of their way to get the milk.

See References for this question.

References

This is the full link to the Haug article used in all of Topic Two--Values and Benefits
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=2039733

Question 1:

• “Comparison of Nutritional Content of Various Milks”   David B. Fankhauser, PhD, Professor  
  University of Cincinnati, Cincinnati, Ohio
  http://biology.clc.uc.edu/fankhauser/Cheese/milk_content.htm
• “Daily Values --A guide for Nutrient Labeling”, University of Texas
   http://www.utexas.edu/courses/ntr311/nutinfo.dvalues.html
• Dietary Supplement Fact Sheet: Calcium” (Chart)  2005 
  The National Institutes of Health Office of Dietary Supplements
•  “Calcium and Milk” 2004
  Harvard University School of Public Health
• “Nutrition Information – Whole Milk” Chart
  http://www.nutritiondata.com/facts
• Dairy Chemistry and Physics”  Douglas Goff, PhD, Professor of Food Science, University of Guelph, Toronto, Canada             http://www.foodsci.uoguelph.ca/dairyedu/chem.html
  http://www.foodsci.uoguelph.ca/dairyedu/chem.html
• “Building Strong Bones: Calcium Information for Health Care Providers”
  The National Institute of Child Health and Human Development (NICHD)
• "Milk’s Unique Nutrient Package”, The National Dairy Council

Books

• MILK Its Remarkable Contribution to Human Health and Well-Being by Stuart Patton, PhD, Professor Emeritus, Food Science, Pennsylvania State University, Transaction Publisher, NJ   2004
• On Food and Cooking, the Science and Lore of the Kitchen by Harold McGee,
   Chapter 1.  Milk and Dairy Products, Scribner, NY, 2004
  http://www.curiouscook.com

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Question 2:

• “Bovine milk in human nutrition – a review”
  Table 1: Additional nutrients in milk and their main health effects, Anna Haug. et al 
  Lipids Health Dis. 2007: 6:25  Published online 2007 September 25. doi: 10.1186/1476-511x-6-25
  http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=2039733
• Nutrient Values and Weight – Milk, whole 3.5% milk fat (chart), USDA
  www.nal.usda.gov/fnic/foodcomp/cgi-bin/list_nut_edit.pl
• “Understanding Milk’s Bioactive Components: A Goal for the Genomics Toolbox”
  by Robert E. Ward and J. Bruce German, Journal of Nutrition, Vol. 134: 962S-967S;  2004
• “Milk and dairy consumption, diabetes and the metabolic syndrome: the Caerphilly prospective study”
   by P.C. Elwood, J.E. Pickering, A.M. Fehily, Journal of Epidemiology and Community Health    Vol. 61, pages 695–698
• “Protein Content of Milk”
  Journal of Dairy Science, Vol. 82 No. 6, 1115–1117, The American Dairy Science Association

Books

• The Family Cow                    
  by Dirk van Loon, Storey Books
• Keeping a Family Cow          
  by Joann S. Grohman, Coburn Press

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Question 3:

Enzymes-

• “Indigenous enzymes in milk: Overview and historical aspects—Part 1 and 2”
  By P.F. Fox, A.L. Kelly; a thorough review with extensive references presented in the first Symposium on Indigenous Enzymes in Milk and later published in the International Dairy Journal, 2006

Mucin-

• “Some Practical Implications of the Milk Mucins”
  Stuart Patton, PhD, Professor Emeritus of food science at Pennsylvania State University Review paper given at a symposium at Michigan State Univ. in 1998 and published in the Journal of Dairy Science.  1999.

Trace Minerals-

• “Adequacy of Trace Minerals in Bovine Milk for Human Consumption”
  By Donald Oberleas, PhD and Ananda S. Prasad, MD, PhD, The American Journal of Clinical Nutrition.  Vol. 22, No.2, Feb. 1969, p 196–199

Allergies & Asthma-

• “Which aspects of the farming lifestyle explain the inverse association with childhood allergy?”
  By Michael R. Perkin, MSc and David P. Strachan, MD, Division of Community Health Sciences of St George’s University of London, London, UK
  Journal Allergy Clinical Immunology 2006; 117:1374–81
• “Unpasteurized milk: health or hazard?”  By M. R. Perkin,
  Division of Community Health Sciences of St George’s University of London, London, UK
  Clinical and Experimental Allergy, 2007; 37, 6227–630
• “Inverse association of farm milk consumption with asthma and allergy in rural and suburban populations across Europe” 
  The PARSIFAL study group (European Union grant)
  Journal compilation © 2006 Blackwell Publishing Ltd, Clinical and Experimental Allergy, 37:661-670
  

Metabolic Syndrome-

• “Dairy May Protect Against Metabolic Syndrome” from:“Milk and Dairy Consumption, Diabetes and the Metabolic Syndrome: the Caerphilly Prospective Study”
  Wales study in 2007 of 20 year follow-up
  By P. C. Elwood, J. E. Pickering, M. Fehily
  Journal of Epidemiology and Community Health, Vol. 61, pages 695–698

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Questions 4, 5:

• Dairy Science and Technology, Second edition CRC Taylor and Francis 2006, P. Walstra, T.M. Jan, T.M. Wouters, and T.J. Geurts. Chapter 7. Heat Treatment and Chapter 9. Homogenization.
• Interview with Dr. John Partridge, Professor at Michigan State University (MSU) Food Science & Human Nutrition
• Grade A Pasteurized Milk Ordinance of 2007 at http://www.michigan.gov/documents/mda/MDA_DP_07PMOFinal_251324_7.pdf

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Question 6:

• Interview with Edwin Blosser, Midwest Bio-Systems
• Interview with Dr. George Bird, Professor of Entomology at MSU
• Interview with Joe Scrimger, Bio-Systems
• Interview with Warnke Family, Warnke's Emerald Acres Farm
• "Outbreaks assoc with unpasteurized milk and soft cheese: an overview of consumer safety", Food Protection Trends April 2009