Raw milk is milk that has not been processed via pasteurization (heating) or homogenization before consumption by humans. The taste is different, and so is the digestability. There is no consensus as to whether it is more healthful or less, compared to treated milk.
Advocates of raw milk often promote:
Many raw milk dairies feature milk from Jersey cattle, which are smaller and produce the richest milk, or from Guernsey cattle, which are slightly larger, and produce slightly larger volumes of slightly less rich milk. Some raw milk dairies, however, raise Holstein cattle, which give huge quanities of less rich milk. Most milk in the US comes from Holsteins.
Buying milk directly from the farm typically means getting milk that is minutes old, or hours old at most, and if properly refrigerated, will keep 8 days, versus the 5-6 days for the much-handled pasteurized milk purchased in a supermarket. Raw milk providers must exercise sanitation on the farm, and healthier herds than pasteurized milk producers must maintain.
Opponents, including the US Food and Drug Administration (FDA) and the group Public Citizen, cite the dangers of pathogens and dispute the health claims. Owing to the lack of pasteurization, raw milk must be produced under strict sanitary conditions, has a shorter shelf life and must be maintained consistently at a low (<40°F) temperature. Despite the restrictions and conditions imposed on producers of raw milk, the FDA has found that "raw milk, no matter how carefully produced, may be unsafe."
Cows with mastitis, an infection of their breast tissue, pass the infecting bacteria into their milk. The most significant bacteria causing bovine mastitis are Streptococcus agalactiae (and other streptococcus species), Staphylococcus aureus, various species of Mycoplasma, and coliform bacteria. These are all human pathogens — they can cause disease in humans.
Cows that carry internal salmonella infections, especially Salmonella dublin, can shed the bacteria in their milk, despite external washing and cleaning of their udders. In addition, many kinds of bacteria can continue to reside on the udders' surface after washings, including salmonella and staphylococcus.
Raw milk is frequently promoted as a "health food", especially to those who are already ill or have compromised immune systems, such as patients with cancer or AIDS. The additional load presented to the immune system from disease-causing bacteria present in raw milk can be too much for the body to bear. A notable opportunistic infector of elderly and immunocompromised patients is Salmonella dublin.
Products made using raw milk, such as cheese and yogurt, may contain the same bacteria as the original milk. These processing methods do not always kill disease-causing bacteria. This is especially true of soft, unaged cheeses. Hard, aged cheeses provide a much less favorable environment for bacterial growth, due to their lower pH and moisture content. Between 2001 and 2004, an outbreak of tuberculosis, which health officials believed to be from unlabelled, illegally imported, Mexican soft raw milk cheese, caused the death of one infant and sickening of dozens of people in New York City. *
Buying "certified" raw milk is no guarantee that the milk is disease-free: many documented cases of Salmonella dublin infection in humans have been caused by consumption of infected certified raw milk. Certification of raw milk is performed by a dairy industry association, not by public health authorities.
Some people say that pasteurized milk converts the protein casein into beta-casomorphin-7, which some in turn link to autism. This argument is based on incorrect knowledge of casein digestion. The process of human digestion, not pasteurization, converts casein into casomorphins (including beta-casomorphin-7) regardless of whether the consumed milk product was pasteurized. Since a person's body creates these byproducts from any casein it encounters, it makes no difference as to the source of the casein, be it from raw or pasteurized milk, cheese, yogurt, etc. In addition, casein and casein micelles are not degraded by pasteurization temperatures *, but are coagulated upon boiling, which explains the different consistency of boiled milk. In regard to total elimination of casein from a person's diet, see gluten-free, casein-free diet for more information on reported effects of this particular diet.
In recent years, however, there has been increased attention placed on the health significance of homogenization. Dr. Kurt A. Oster's studies from the 1960s to the 1980s suggest that homogenized milk is a major factor in plaque formation, causing heart disease.
Atherosclerosis begins with a small wound or lesion in the wall of the artery. Oster reasoned that the initial lesion was caused by the loss of plasmalogen from the cells lining the artery, leading to the development of plaque. He believed that the enzyme xanthine oxidase (XO) has the capacity to oxidize, or change, plasmalogen into a different substance, making it appear that the plasmalogen had disappeared.
Oster and partner Ross investigated cow's milk, "…presently under investigation in this laboratory since it has been shown that milk antibodies are significantly elevated in the blood of male patients with heart disease." Homogenization became widespread in the United States in the 1930s and nearly universal in the 1940s - which is when atherosclerotic heart disease began to skyrocket. Oster theorized that the homogenization of milk somehow increased the biological availability of xanthine oxidase.
Oster asserted that XO is found on the membrane of the fat globules in milk. Homogenization, on the other hand, would encapsulate the XO, so that it would not be digested in the stomach and intestines, but enter the bloodstream, where it caused its damage.
Auguste Gaulin's 1899 patent on homogenization forced milk through fine holes to reduce the size of fat globules. At 15 MPa, pasteurization multiplies the fat globules 600-fold in number, while reducing mean size from 3.3 to 0.4 micrometres.
Neither opponents nor proponents of the xanthine oxidase/plasmalogen hypothesis have presented convincing evidence in all of their writings, but the debate is hardly over. Research by RJ Hajjar and JA Leopold resulted in the 2006 study, "Xanthine oxidase inhibition and heart failure: novel therapeutic strategy for ventricular dysfunction", published in the American Heart Association journal Circulation Research
That does not mean raw milk is unavailable in the other 46 states. In Indiana, for instance, it is illegal for a dairy to sell raw milk, but consumers are able to lease cows and obtain raw milk that way. In Ohio, state law prohibits dairies from selling raw milk unless they had continuously offered it since before 1965. Raw milk was available until 2003, when the state pressured Young's Jersey Farm in Yellow Springs, Ohio into voluntarily giving up their raw milk license, by threatening them with loss of their pasteurized milk license as well. The state was experiencing an outbreak of salmonella which affected some employees at Young's, but which was not traced to Young's products. Young's not only offered raw whole milk, but skim milk, cream, butter, and ice cream made from their own raw milk. Jersey cows are a breed known for producing smaller quantities of exceptionally rich milk; most dairy farmers raise Holsteins, which produce huge quantities of thinner milk.
Raw milk may be purchased from the farm, under varying restrictions, in 28 states. In California, Connecticut, Maine, New Mexico and South Carolina, it may be purchased in stores. In every state but Michigan, raw milk may be purchased for animal consumption.
In Pennsylvania, it is fairly easy for dairies to begin selling raw milk on the farm, and when the farm economy periodically suffers, new producers enter the marketplace. The state requires far more frequent inspections and lab testing of raw milk producers, however, and while farmers frequently begin selling raw milk, many soon abandon it, finding the cost and effort of handling milk properly and keeping the herd healthy to be unacceptable.
The sale of raw milk directly to consumers is prohibited in Canada. *. However, Canada, and all 50 United States, permit the sale of raw milk cheeses that are aged for at least 60 days.
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