United States raw milk debate
Encyclopedia
The United States raw milk debate concerns issues of food safety and claimed health benefits of raw (un-pasteurized, un-homogenized
) milk
, and whether authorities responsible for regulating food safety
should prohibit sale of raw milk
for consumption.
Raw milk, commonly and historically consumed by farm families, makes up a small proportion of US general population milk consumption. However, some claim the demand for raw milk has "considerably increased in recent years". Raw milk advocates claim a variety of health benefits attributable to untreated dairy products; government officials and scientific researchers stress that there are substantial food safety risks associated with raw milk and that claims of health benefits provided by raw milk are unsupported by scientific evidence.
s, sugar
s, vitamin
s, and mineral
s. If the globules are large enough, as with unprocessed milk from cows, the fat globules float upwards until they form a distinct cream
layer at the top. Some animals, such as goat
s, produce smaller fat globules that remain mixed unless mechanically separated by centrifugation
.
Homogenization is a process that reduces the size of fat globules by forcing pressurized, hot milk through small holes, causing turbulence that breaks up the larger fat globules so that they remain suspended rather than separating in a cream layer at the top. The purpose of homogenization is to make milk more convenient to process, store and consume, eliminating the need to shake or stir the milk container to remix the separated cream layer and increasing the shelf-life of the product.
Those opposed to homogenization argue that decreasing the size of fat globules may have unhealthy effects, including allowing steroid
and protein hormone
s to bypass normal digestion
and increase their levels in the body. Concerns that uptake of the protein xanthine oxidase
is increased by homogenization, leading to hardening of the arteries (atherosclerosis
), were raised in the 1970s. Subsequent research "failed to substantiate, and in many cases has refuted" a plausible effect of xanthine oxidase from homogenized milk on cardiovascular disease.
Scientific studies are somewhat limited but do not currently support claims that milk homogenization affects the development of atherosclerosis, coronary heart disease
, milk allergy
and milk intolerance, Type I diabetes or Type II diabetes.
s, followed by rapid cooling. While different times and temperatures may be used by different processors, pasteurization is most commonly achieved with heating to 161 degrees Fahrenheit (71.7 degrees Celsius) for 15 seconds. Milk is tested following pasteurization to confirm that bacteria have been killed to an acceptable level. Pasteurization kills pathogenic bacteria which occasionally may be present in milk, including those causing tuberculosis
(Mycobacterium bovis
), listeriosis (Listeria monocytogenes), Q fever
(Coxiella burnetii
), brucellosis
(Brucella
), campylobacteriosis
(Campylobacter
), salmonellosis
(Salmonella
), and several other foodborne illness
es (e.g., Escherichia coli O157:H7
). Pasteurization may not kill some resistant bacteria, which can eventually cause souring and spoilage of fresh milk. UHT pasteurization (Ultra High Temperature) is a more extreme form of pasteurization heating milk to a temperature high enough to kill spoilage organisms also.
Pasteurization is widely accepted to improve the safety of milk products by reducing the exposure to pathogens. Opponents of pasteurization argue that unpasteurized milk has benefits associated with superior taste, nutritional qualities and certain health benefits over pasteurized milk. While pasteurization of milk kills off bacterial pathogens, other bacteria species with possible health benefits are also destroyed. A 2009 systematic review
of the food safety of unpasteurized milk concluded that science-based data to substantiate claims of health benefits "are lacking or do not exist" and the risks associated with disease outbreaks as a result of raw milk consumption are "considerably higher".
, that could be easily transmitted to humans through the drinking of raw milk. Initially after the scientific discovery of bacteria, no product testing was available to determine if a farmer's milk was safe or infected, so all milk had to be treated as potentially contagious. After the first test was developed, some farmers actively worked to prevent their infected animals from being killed and removed from food production, or would falsify the test results so that their animals would appear to be free of infection.
In the United States, milk pasteurization became "widespread" in the 1920s and it was considered "one of the major breakthroughs in public health". Pasteurization is credited with reducing infectious-disease rates in the U.S. "more than 90% over the past century". In 1924, "Grade A Pasteurization" became recommended federal policy, but interstate commerce of unpasteurized dairy products was only limited via federal legislation in 1987.
, California
and Washington allow raw milk sales in retail stores with appropriate warning labeling. As of May 2010, Massachusetts
only allows direct sales from farm to consumer, resulting in "buying clubs" where consumers pool transportation resources to obtain raw milk more conveniently.
In late 2007, the debate received media attention in California, where limits on the bacterial counts legally allowed in commercial raw milk came up for legislative review. Reuters
named the raw milk debate as first on a list of the top eight health issues of 2008. The FDA has also offered financial assistance to state departments of health to help reduce raw milk consumption.
or gastrointestinal disorders. A 2006 systematic review
of infections associated with raw milk contends that pasteurized milk is substantially safer than raw milk, and comparably nutritious to raw milk, therefore there is no scientific reason for choosing raw milk products.
Pasteurization opponents say that raw milk contains bacteria beneficial to the human digestive system, but pasteurization is not selective and impacts all bacteria whether beneficial or infectious. These bacteria include species considered to be probiotic
s, such as Lactobacillus acidophilus
, useful for the culturing of yogurt and cheese
. Milk products with L. acidophilus, have been associated with decreased incidence of pediatric diarrhea, decreased levels of toxic amine
s in the blood of dialysis
patients with small bowel bacterial overgrowth, aided lactose
digestion in lactose-intolerant subjects, and a reduction in coronary heart disease
risks. However, food scientists and FDA officials maintain that such "good bacteria" can be found in pasteurized products, including yogurt, and argue that the destruction of pathogens far outweighs any proposed benefit to keeping the "beneficial" microbes alive.
According to the Center for Disease Control and Prevention, more than 300 people in the United States got sick from drinking raw milk or eating cheese made from raw milk in 2001, and nearly 200 became ill from these products in 2002. "Drinking raw milk or eating raw milk products is like playing Russian roulette with your health," says John Sheehan, director of the Food and Drug Administration
's Division of Dairy and Egg Safety. "We see a number of cases of food-borne illness every year related to the consumption of raw milk."
In 2006, the California Department of Food and Agriculture temporarily quarantined milk and cream from Organic Pastures, California's largest raw milk producer, after four children were stricken with E. coli O157:H7 bacterial illness. The department determined that the common link in all four cases "was consumption of raw milk or raw colostrum
from Organic Pastures in the week prior to symptom onset."
Milk collected or stored in unsanitary conditions may harbor a host of disease-causing organisms (pathogens), such as tuberculosis (Mycobacterium bovis
), the bacteria Campylobacter (Campylobacteriosis
), Escherichia E. coli O157:H7), Listeria (Listeriosis), Salmonella (Salmonellosis
), Yersinia (Yersinia enterocolitica
), and Brucella (Brucellosis
). Pasteurization consistently removes all of these pathogens, though they can be reintroduced if the product is handled carelessly. Thus dairy farms that pasteurize their milk can have unsanitary facilities without the attendent outbreaks of disease that would occur if a raw milk dairy kept its herds in similar unsanitary conditions.
People with weakened immune system
s, such as elderly, children, and those with certain diseases or conditions, are most at risk for severe infections from pathogens that can contaminate raw milk. In pregnant women, Listeria monocytogenes-caused illness can result in miscarriage, fetal death, or illness or death of a newborn infant, and Escherichia coli (E. coli) infection has been linked to hemolytic uremic syndrome, a condition that can cause kidney failure and death. Other groups, such as the Center for Food Safety and Applied Nutrition
and American Academy of Pediatrics
, also warn that raw milk is dangerous, especially for children.
The Centers for Disease Control (CDC) cite numerous cases of serious or fatal infections caused by raw milk, with E. coli O157:H7 being the most important because it can cause hemolytic-uremic syndrome
, a life-threatening condition. In a CDC report, numerous cases were traced to raw milk from a cow-share program in Cowlitz County, Washington
. After five children were hospitalized, a court order was issued to bring the farm into compliance. In 2007, Kansas State University
published a list of outbreaks associated with consuming raw milk or dairy products and an article about the investigation of raw milk outbreaks.
The Weston A. Price Foundation has been active in promoting raw milk with its "Real Milk" campaign. The organization claims that of 15 milkbourne disease outbreaks cited by the FDA, not a single one demonstrated that pasteurization would have fixed the problem, that 93% lacked either a valid statistical correlation with raw milk or a positive sample, and half lacked both; they further claimed that, even with the FDA's numbers, raw milk was no more dangerous than deli meats. In response, the director of the FDA's division of plant- and dairy-food safety, John Sheehan, called the organization's claims on the health benefits and safety of raw milk "false, devoid of scientific support, and misleading to consumers".
In 2008, scientists discovered that raw milk contains more bacteria than previously thought and identified Chryseobacterium
oranimense as well as C. haifense and C. bovis, but the amount found in raw milk has not been proven harmful.
s, that cannot survive the heating process and may be destroyed during pasteurization; specifically, immunoglobulins and the enzyme
s lipase
and phosphatase
, which are inactivated by heat, are believed to be beneficial. In contrast, food scientists and FDA officials assert that most "beneficial" enzymes survive pasteurization and that humans do not use animal enzymes to metabolize nutrients.
Raw milk contains vitamin B6
, but the heat treatment may cause as much as 20% of the vitamin to be lost. Pasteurization does cause the loss of several vitamin
s, but only approximately 0-10%. Raw milk contains very little vitamin D
, which is added to processed milk.
and allergies.
The Raw Milk Cheesemakers Association hold that cheeses produced from raw milk have distinctive complexity and depth of flavor absent from pasteurized-milk cheeses.
The FDA considers hard, aged cheeses, such as parmesan and cheddar
, made from raw milk to be generally safe for consumption; soft cheeses made from raw milk are considered unsafe. These cheeses are currently legally sold if aged for 60 days or more. Over this period, the salt
and acid
characteristics of aging cheeses generally eliminate the growth of pathogenic bacteria.
and personal choice arguments against government interference concerning the sale of raw milk. Some such advocates may feel resentment towards the government's efforts in limiting the distribution and consumption of raw milk, seeing their actions as a personal choice that is not harmful to anyone else. Raw milk activism can be associated with alternative medicine
and anti-regulatory activism.
. These grades are typically related to a measurement known as the somatic cell count
(SCC) and the bacteria plate count. Generally a lower somatic cell count indicates better animal health, while the bacteria plate count indicates improved equipment sanitation.
Somatic cells originate only from inside the animal's udder
, while bacteria are usually from external contamination, such as insufficient cleaning of the milk transport equipment or insufficient external cleansing of the cow's udder and teats prior to milking. Milking equipment can also be accidentally knocked or kicked off an animal onto the floor, and contaminants on the barn floor can be sucked into the milk line by the system vacuum. A filter sock or filter disk in the pipeline prevents large particulate contaminants from entering the milk bulk tank, but cannot remove bacterial contamination once it has occurred.
For example as defined by the State of Indiana administrative code, Grade A milk shall meet the following standards:
As established, these measurements are taken daily from the milk bulk tank
and not from individual cows. This is because testing of individual animals at each milking would be expensive, but it also means that milk from a sick cow is diluted and averaged down by the healthy animals. Greater bulk tanks at very great commercial farms are accommodating of more sick animals in the herd, without the sick animals affecting the overall milk quality rating.
As discussed in the paper Guidelines for Using the DHI Somatic Cell Count Program
Bacteria in milk can come from sources other than the animal. Over time the milking pipeline
and equipment can become coated with residues such as milkstone which are not removed by standard detergents and require periodic flushing of equipment with high strength corrosives. Automatic washing equipment for the bulk tank
may not effectively clean all interior surfaces, and does not clean the exterior of the bulk tank at all.
Some buyers award producers for having the lowest SCC but this does not also lead to an increased payment for the milk quality, so there is no incentive to strive for anything more than meeting the basic grade A SCC rating.
Homogenization (chemistry)
Homogenization or homogenisation is any of several processes used to make a chemical mixture the same throughout.-Definition:Homogenization is intensive blending of mutually related substances or groups of mutually related substances to form a constant of different insoluble phases to obtain a...
) milk
Milk
Milk is a white liquid produced by the mammary glands of mammals. It is the primary source of nutrition for young mammals before they are able to digest other types of food. Early-lactation milk contains colostrum, which carries the mother's antibodies to the baby and can reduce the risk of many...
, and whether authorities responsible for regulating food safety
Food safety
Food safety is a scientific discipline describing handling, preparation, and storage of food in ways that prevent foodborne illness. This includes a number of routines that should be followed to avoid potentially severe health hazards....
should prohibit sale of raw milk
Raw milk
Raw milk is milk that has not been pasteurized or homogenized.-History:Humans consumed raw milk exclusively prior to the industrial revolution and the invention of the pasteurization process in 1864. During the industrial revolution large populations congregated into urban areas detached from the...
for consumption.
Raw milk, commonly and historically consumed by farm families, makes up a small proportion of US general population milk consumption. However, some claim the demand for raw milk has "considerably increased in recent years". Raw milk advocates claim a variety of health benefits attributable to untreated dairy products; government officials and scientific researchers stress that there are substantial food safety risks associated with raw milk and that claims of health benefits provided by raw milk are unsupported by scientific evidence.
Homogenization
Unprocessed milk consists of globules of milk fat suspended in a watery base containing dissolved proteinProtein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
s, sugar
Sugar
Sugar is a class of edible crystalline carbohydrates, mainly sucrose, lactose, and fructose, characterized by a sweet flavor.Sucrose in its refined form primarily comes from sugar cane and sugar beet...
s, vitamin
Vitamin
A vitamin is an organic compound required as a nutrient in tiny amounts by an organism. In other words, an organic chemical compound is called a vitamin when it cannot be synthesized in sufficient quantities by an organism, and must be obtained from the diet. Thus, the term is conditional both on...
s, and mineral
Mineral
A mineral is a naturally occurring solid chemical substance formed through biogeochemical processes, having characteristic chemical composition, highly ordered atomic structure, and specific physical properties. By comparison, a rock is an aggregate of minerals and/or mineraloids and does not...
s. If the globules are large enough, as with unprocessed milk from cows, the fat globules float upwards until they form a distinct cream
Cream
Cream is a dairy product that is composed of the higher-butterfat layer skimmed from the top of milk before homogenization. In un-homogenized milk, over time, the lighter fat rises to the top. In the industrial production of cream this process is accelerated by using centrifuges called "separators"...
layer at the top. Some animals, such as goat
Goat
The domestic goat is a subspecies of goat domesticated from the wild goat of southwest Asia and Eastern Europe. The goat is a member of the Bovidae family and is closely related to the sheep as both are in the goat-antelope subfamily Caprinae. There are over three hundred distinct breeds of...
s, produce smaller fat globules that remain mixed unless mechanically separated by centrifugation
Centrifugation
Centrifugation is a process that involves the use of the centrifugal force for the sedimentation of mixtures with a centrifuge, used in industry and in laboratory settings. More-dense components of the mixture migrate away from the axis of the centrifuge, while less-dense components of the mixture...
.
Homogenization is a process that reduces the size of fat globules by forcing pressurized, hot milk through small holes, causing turbulence that breaks up the larger fat globules so that they remain suspended rather than separating in a cream layer at the top. The purpose of homogenization is to make milk more convenient to process, store and consume, eliminating the need to shake or stir the milk container to remix the separated cream layer and increasing the shelf-life of the product.
Those opposed to homogenization argue that decreasing the size of fat globules may have unhealthy effects, including allowing steroid
Steroid
A steroid is a type of organic compound that contains a characteristic arrangement of four cycloalkane rings that are joined to each other. Examples of steroids include the dietary fat cholesterol, the sex hormones estradiol and testosterone, and the anti-inflammatory drug dexamethasone.The core...
and protein hormone
Hormone
A hormone is a chemical released by a cell or a gland in one part of the body that sends out messages that affect cells in other parts of the organism. Only a small amount of hormone is required to alter cell metabolism. In essence, it is a chemical messenger that transports a signal from one...
s to bypass normal digestion
Digestion
Digestion is the mechanical and chemical breakdown of food into smaller components that are more easily absorbed into a blood stream, for instance. Digestion is a form of catabolism: a breakdown of large food molecules to smaller ones....
and increase their levels in the body. Concerns that uptake of the protein xanthine oxidase
Xanthine oxidase
Xanthine oxidase Xanthine oxidase Xanthine oxidase (XO (sometimes 'XAO'), a form of xanthine oxidoreductase that generates reactive oxygen species. Is an enzyme that catalyzes the oxidation of hypoxanthine to xanthine and can further catalyze the oxidation of xanthine to uric acid...
is increased by homogenization, leading to hardening of the arteries (atherosclerosis
Atherosclerosis
Atherosclerosis is a condition in which an artery wall thickens as a result of the accumulation of fatty materials such as cholesterol...
), were raised in the 1970s. Subsequent research "failed to substantiate, and in many cases has refuted" a plausible effect of xanthine oxidase from homogenized milk on cardiovascular disease.
Scientific studies are somewhat limited but do not currently support claims that milk homogenization affects the development of atherosclerosis, coronary heart disease
Coronary heart disease
Coronary artery disease is the end result of the accumulation of atheromatous plaques within the walls of the coronary arteries that supply the myocardium with oxygen and nutrients. It is sometimes also called coronary heart disease...
, milk allergy
Milk allergy
A milk allergy is a food allergy, an adverse immune reaction to one or more of the constituents of milk from any animal...
and milk intolerance, Type I diabetes or Type II diabetes.
Pasteurization
Pasteurization is a sanitation process in which milk is heated briefly to a temperature high enough to kill pathogenPathogen
A pathogen gignomai "I give birth to") or infectious agent — colloquially, a germ — is a microbe or microorganism such as a virus, bacterium, prion, or fungus that causes disease in its animal or plant host...
s, followed by rapid cooling. While different times and temperatures may be used by different processors, pasteurization is most commonly achieved with heating to 161 degrees Fahrenheit (71.7 degrees Celsius) for 15 seconds. Milk is tested following pasteurization to confirm that bacteria have been killed to an acceptable level. Pasteurization kills pathogenic bacteria which occasionally may be present in milk, including those causing tuberculosis
Tuberculosis
Tuberculosis, MTB, or TB is a common, and in many cases lethal, infectious disease caused by various strains of mycobacteria, usually Mycobacterium tuberculosis. Tuberculosis usually attacks the lungs but can also affect other parts of the body...
(Mycobacterium bovis
Mycobacterium bovis
Mycobacterium bovis is a slow-growing , aerobic bacterium and the causative agent of tuberculosis in cattle...
), listeriosis (Listeria monocytogenes), Q fever
Q fever
Q fever is a disease caused by infection with Coxiella burnetii, a bacterium that affects humans and other animals. This organism is uncommon but may be found in cattle, sheep, goats and other domestic mammals, including cats and dogs...
(Coxiella burnetii
Coxiella burnetii
Coxiella burnetii is an obligate intracellular bacterial pathogen, and is the causative agent of Q fever. The genus Coxiella is morphologically similar to Rickettsia, but with a variety of genetic and physiological differences. C...
), brucellosis
Brucellosis
Brucellosis, also called Bang's disease, Crimean fever, Gibraltar fever, Malta fever, Maltese fever, Mediterranean fever, rock fever, or undulant fever, is a highly contagious zoonosis caused by ingestion of unsterilized milk or meat from infected animals or close contact with their secretions...
(Brucella
Brucella
Brucella is a genus of Gram-negative bacteria. They are small , non-motile, non-encapsulated coccobacilli, which function as facultative intracellular parasites....
), campylobacteriosis
Campylobacteriosis
Campylobacteriosis is an infection by the Campylobacter bacterium, most commonly C. jejuni. It is among the most common bacterial infections of humans, often a foodborne illness. It produces an inflammatory, sometimes bloody, diarrhea or dysentery syndrome, mostly including cramps, fever and...
(Campylobacter
Campylobacter
Campylobacter is a genus of bacteria that are Gram-negative, spiral, and microaerophilic. Motile, with either unipolar or bipolar flagella, the organisms have a characteristic spiral/corkscrew appearance and are oxidase-positive. Campylobacter jejuni is now recognized as one of the main causes...
), salmonellosis
Salmonellosis
Salmonellosis is an infection with Salmonella bacteria. Most people infected with Salmonella develop diarrhea, fever, vomiting, and abdominal cramps 12 to 72 hours after infection. In most cases, the illness lasts four to seven days, and most people recover without treatment...
(Salmonella
Salmonella
Salmonella is a genus of rod-shaped, Gram-negative, non-spore-forming, predominantly motile enterobacteria with diameters around 0.7 to 1.5 µm, lengths from 2 to 5 µm, and flagella which grade in all directions . They are chemoorganotrophs, obtaining their energy from oxidation and reduction...
), and several other foodborne illness
Foodborne illness
Foodborne illness is any illness resulting from the consumption of contaminated food, pathogenic bacteria, viruses, or parasites that contaminate food, as well as chemical or natural toxins such as poisonous mushrooms.-Causes:Foodborne illness usually arises from improper handling, preparation, or...
es (e.g., Escherichia coli O157:H7
Escherichia coli O157:H7
Escherichia coli O157:H7 is an enterohemorrhagic strain of the bacterium Escherichia coli and a cause of foodborne illness. Infection often leads to hemorrhagic diarrhea, and occasionally to kidney failure, especially in young children and elderly persons...
). Pasteurization may not kill some resistant bacteria, which can eventually cause souring and spoilage of fresh milk. UHT pasteurization (Ultra High Temperature) is a more extreme form of pasteurization heating milk to a temperature high enough to kill spoilage organisms also.
Pasteurization is widely accepted to improve the safety of milk products by reducing the exposure to pathogens. Opponents of pasteurization argue that unpasteurized milk has benefits associated with superior taste, nutritional qualities and certain health benefits over pasteurized milk. While pasteurization of milk kills off bacterial pathogens, other bacteria species with possible health benefits are also destroyed. A 2009 systematic review
Systematic review
A systematic review is a literature review focused on a research question that tries to identify, appraise, select and synthesize all high quality research evidence relevant to that question. Systematic reviews of high-quality randomized controlled trials are crucial to evidence-based medicine...
of the food safety of unpasteurized milk concluded that science-based data to substantiate claims of health benefits "are lacking or do not exist" and the risks associated with disease outbreaks as a result of raw milk consumption are "considerably higher".
History
Pasteurization was first used in the United States in the 1890s after the discovery of germ theory to control the hazards of highly contagious bacterial diseases, including bovine tuberculosis and brucellosisBrucellosis
Brucellosis, also called Bang's disease, Crimean fever, Gibraltar fever, Malta fever, Maltese fever, Mediterranean fever, rock fever, or undulant fever, is a highly contagious zoonosis caused by ingestion of unsterilized milk or meat from infected animals or close contact with their secretions...
, that could be easily transmitted to humans through the drinking of raw milk. Initially after the scientific discovery of bacteria, no product testing was available to determine if a farmer's milk was safe or infected, so all milk had to be treated as potentially contagious. After the first test was developed, some farmers actively worked to prevent their infected animals from being killed and removed from food production, or would falsify the test results so that their animals would appear to be free of infection.
In the United States, milk pasteurization became "widespread" in the 1920s and it was considered "one of the major breakthroughs in public health". Pasteurization is credited with reducing infectious-disease rates in the U.S. "more than 90% over the past century". In 1924, "Grade A Pasteurization" became recommended federal policy, but interstate commerce of unpasteurized dairy products was only limited via federal legislation in 1987.
Legal status
In 2009, 29 U.S. states allowed sales of raw milk in some form. In other parts of the world, raw milk can often be bought directly from the farmer. ArizonaArizona
Arizona ; is a state located in the southwestern region of the United States. It is also part of the western United States and the mountain west. The capital and largest city is Phoenix...
, California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
and Washington allow raw milk sales in retail stores with appropriate warning labeling. As of May 2010, Massachusetts
Massachusetts
The Commonwealth of Massachusetts is a state in the New England region of the northeastern United States of America. It is bordered by Rhode Island and Connecticut to the south, New York to the west, and Vermont and New Hampshire to the north; at its east lies the Atlantic Ocean. As of the 2010...
only allows direct sales from farm to consumer, resulting in "buying clubs" where consumers pool transportation resources to obtain raw milk more conveniently.
In late 2007, the debate received media attention in California, where limits on the bacterial counts legally allowed in commercial raw milk came up for legislative review. Reuters
Reuters
Reuters is a news agency headquartered in New York City. Until 2008 the Reuters news agency formed part of a British independent company, Reuters Group plc, which was also a provider of financial market data...
named the raw milk debate as first on a list of the top eight health issues of 2008. The FDA has also offered financial assistance to state departments of health to help reduce raw milk consumption.
Health effects of pasteurized milk
Pasteurization is credited with dramatically reducing pathogens found in milk. This improves the shelf-life and safety of the processed milk. Advocates of drinking raw milk claim various health benefits they attribute to raw milk that are lost in the pasteurization process, and claim that raw milk can be produced as hygienically as pasteurized milk. Raw milk advocates may go as far as to claim that untreated milk is a "miracle cure" for illnesses such as asthmaAsthma
Asthma is the common chronic inflammatory disease of the airways characterized by variable and recurring symptoms, reversible airflow obstruction, and bronchospasm. Symptoms include wheezing, coughing, chest tightness, and shortness of breath...
or gastrointestinal disorders. A 2006 systematic review
Systematic review
A systematic review is a literature review focused on a research question that tries to identify, appraise, select and synthesize all high quality research evidence relevant to that question. Systematic reviews of high-quality randomized controlled trials are crucial to evidence-based medicine...
of infections associated with raw milk contends that pasteurized milk is substantially safer than raw milk, and comparably nutritious to raw milk, therefore there is no scientific reason for choosing raw milk products.
Pasteurization opponents say that raw milk contains bacteria beneficial to the human digestive system, but pasteurization is not selective and impacts all bacteria whether beneficial or infectious. These bacteria include species considered to be probiotic
Probiotic
Probiotics are live microorganisms thought to be beneficial to the host organism. According to the currently adopted definition by FAO/WHO, probiotics are: "Live microorganisms which when administered in adequate amounts confer a health benefit on the host"...
s, such as Lactobacillus acidophilus
Lactobacillus acidophilus
Lactobacillus acidophilus is a species in the genus Lactobacillus. L. acidophilus is a homofermentative species, fermenting sugars into lactic acid, which grows readily at rather low pH values and has an optimum growth temperature of 37 °C . L...
, useful for the culturing of yogurt and cheese
Cheese
Cheese is a generic term for a diverse group of milk-based food products. Cheese is produced throughout the world in wide-ranging flavors, textures, and forms....
. Milk products with L. acidophilus, have been associated with decreased incidence of pediatric diarrhea, decreased levels of toxic amine
Amine
Amines are organic compounds and functional groups that contain a basic nitrogen atom with a lone pair. Amines are derivatives of ammonia, wherein one or more hydrogen atoms have been replaced by a substituent such as an alkyl or aryl group. Important amines include amino acids, biogenic amines,...
s in the blood of dialysis
Dialysis
In medicine, dialysis is a process for removing waste and excess water from the blood, and is primarily used to provide an artificial replacement for lost kidney function in people with renal failure...
patients with small bowel bacterial overgrowth, aided lactose
Lactose
Lactose is a disaccharide sugar that is found most notably in milk and is formed from galactose and glucose. Lactose makes up around 2~8% of milk , although the amount varies among species and individuals. It is extracted from sweet or sour whey. The name comes from or , the Latin word for milk,...
digestion in lactose-intolerant subjects, and a reduction in coronary heart disease
Coronary heart disease
Coronary artery disease is the end result of the accumulation of atheromatous plaques within the walls of the coronary arteries that supply the myocardium with oxygen and nutrients. It is sometimes also called coronary heart disease...
risks. However, food scientists and FDA officials maintain that such "good bacteria" can be found in pasteurized products, including yogurt, and argue that the destruction of pathogens far outweighs any proposed benefit to keeping the "beneficial" microbes alive.
Pathogens and public health concerns
According to a 2009 review, milkbourne disease outbreaks made up approximately 25% of all food and water contamination disease outbreaks in 1938; pasturization is largely credited for a dramatic decrease in milkbourne disease outbreaks, which made up less than 1% of food and water contamination disease outbreaks by 2005.According to the Center for Disease Control and Prevention, more than 300 people in the United States got sick from drinking raw milk or eating cheese made from raw milk in 2001, and nearly 200 became ill from these products in 2002. "Drinking raw milk or eating raw milk products is like playing Russian roulette with your health," says John Sheehan, director of the Food and Drug Administration
Food and Drug Administration
The Food and Drug Administration is an agency of the United States Department of Health and Human Services, one of the United States federal executive departments...
's Division of Dairy and Egg Safety. "We see a number of cases of food-borne illness every year related to the consumption of raw milk."
In 2006, the California Department of Food and Agriculture temporarily quarantined milk and cream from Organic Pastures, California's largest raw milk producer, after four children were stricken with E. coli O157:H7 bacterial illness. The department determined that the common link in all four cases "was consumption of raw milk or raw colostrum
Colostrum
Colostrum is a form of milk produced by the mammary glands of mammals in late pregnancy. Most species will generate colostrum just prior to giving birth...
from Organic Pastures in the week prior to symptom onset."
Milk collected or stored in unsanitary conditions may harbor a host of disease-causing organisms (pathogens), such as tuberculosis (Mycobacterium bovis
Mycobacterium bovis
Mycobacterium bovis is a slow-growing , aerobic bacterium and the causative agent of tuberculosis in cattle...
), the bacteria Campylobacter (Campylobacteriosis
Campylobacteriosis
Campylobacteriosis is an infection by the Campylobacter bacterium, most commonly C. jejuni. It is among the most common bacterial infections of humans, often a foodborne illness. It produces an inflammatory, sometimes bloody, diarrhea or dysentery syndrome, mostly including cramps, fever and...
), Escherichia E. coli O157:H7), Listeria (Listeriosis), Salmonella (Salmonellosis
Salmonellosis
Salmonellosis is an infection with Salmonella bacteria. Most people infected with Salmonella develop diarrhea, fever, vomiting, and abdominal cramps 12 to 72 hours after infection. In most cases, the illness lasts four to seven days, and most people recover without treatment...
), Yersinia (Yersinia enterocolitica
Yersinia enterocolitica
Yersinia enterocolitica is a species of gram-negative coccobacillus-shaped bacterium, belonging to the family Enterobacteriaceae. Yersinia enterocolitica infection causes the disease yersiniosis, which is a zoonotic disease occurring in humans as well as a wide array of animals such as cattle,...
), and Brucella (Brucellosis
Brucellosis
Brucellosis, also called Bang's disease, Crimean fever, Gibraltar fever, Malta fever, Maltese fever, Mediterranean fever, rock fever, or undulant fever, is a highly contagious zoonosis caused by ingestion of unsterilized milk or meat from infected animals or close contact with their secretions...
). Pasteurization consistently removes all of these pathogens, though they can be reintroduced if the product is handled carelessly. Thus dairy farms that pasteurize their milk can have unsanitary facilities without the attendent outbreaks of disease that would occur if a raw milk dairy kept its herds in similar unsanitary conditions.
People with weakened immune system
Immune system
An immune system is a system of biological structures and processes within an organism that protects against disease by identifying and killing pathogens and tumor cells. It detects a wide variety of agents, from viruses to parasitic worms, and needs to distinguish them from the organism's own...
s, such as elderly, children, and those with certain diseases or conditions, are most at risk for severe infections from pathogens that can contaminate raw milk. In pregnant women, Listeria monocytogenes-caused illness can result in miscarriage, fetal death, or illness or death of a newborn infant, and Escherichia coli (E. coli) infection has been linked to hemolytic uremic syndrome, a condition that can cause kidney failure and death. Other groups, such as the Center for Food Safety and Applied Nutrition
Center for Food Safety and Applied Nutrition
The Center for Food Safety and Applied Nutrition is the branch of the United States Food and Drug Administration that regulates food, dietary supplements, and cosmetics .-Area of regulation:...
and American Academy of Pediatrics
American Academy of Pediatrics
The American Academy of Pediatrics is the major professional association of pediatricians in the United States. The AAP was founded in 1930 by 35 pediatricians to address pediatric healthcare standards. It currently has 60,000 members in primary care and sub-specialist areas...
, also warn that raw milk is dangerous, especially for children.
The Centers for Disease Control (CDC) cite numerous cases of serious or fatal infections caused by raw milk, with E. coli O157:H7 being the most important because it can cause hemolytic-uremic syndrome
Hemolytic-uremic syndrome
Hemolytic-uremic syndrome , abbreviated HUS, is a disease characterized by hemolytic anemia, acute renal failure and a low platelet count . It predominantly, but not exclusively, affects children. Most cases are preceded by an episode of diarrhea caused by E. coli O157:H7, which is acquired as a...
, a life-threatening condition. In a CDC report, numerous cases were traced to raw milk from a cow-share program in Cowlitz County, Washington
Cowlitz County, Washington
Cowlitz County is a county located in the U.S. state of Washington. As of the 2010 census its population was 102,410. It forms the Longview, Washington, Metropolitan Statistical Area which encompasses all of Cowlitz County. The county seat is at Kelso, and its largest city is Longview...
. After five children were hospitalized, a court order was issued to bring the farm into compliance. In 2007, Kansas State University
Kansas State University
Kansas State University, commonly shortened to K-State, is an institution of higher learning located in Manhattan, Kansas, in the United States...
published a list of outbreaks associated with consuming raw milk or dairy products and an article about the investigation of raw milk outbreaks.
The Weston A. Price Foundation has been active in promoting raw milk with its "Real Milk" campaign. The organization claims that of 15 milkbourne disease outbreaks cited by the FDA, not a single one demonstrated that pasteurization would have fixed the problem, that 93% lacked either a valid statistical correlation with raw milk or a positive sample, and half lacked both; they further claimed that, even with the FDA's numbers, raw milk was no more dangerous than deli meats. In response, the director of the FDA's division of plant- and dairy-food safety, John Sheehan, called the organization's claims on the health benefits and safety of raw milk "false, devoid of scientific support, and misleading to consumers".
In 2008, scientists discovered that raw milk contains more bacteria than previously thought and identified Chryseobacterium
Chryseobacterium
Chryseobacterium is a genus of Gram-negative bacteria. Three novel cold-tolerant species of Chryseobacterium, C. oranimense C. haifense, and C. bovis, have been detected in raw milk in Israel....
oranimense as well as C. haifense and C. bovis, but the amount found in raw milk has not been proven harmful.
Nutrients in milk
Advocates of drinking raw milk claim raw milk contains desirable substances, such as enzymeEnzyme
Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...
s, that cannot survive the heating process and may be destroyed during pasteurization; specifically, immunoglobulins and the enzyme
Enzyme
Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...
s lipase
Lipase
A lipase is an enzyme that catalyzes the formation or cleavage of fats . Lipases are a subclass of the esterases.Lipases perform essential roles in the digestion, transport and processing of dietary lipids in most, if not all, living organisms...
and phosphatase
Phosphatase
A phosphatase is an enzyme that removes a phosphate group from its substrate by hydrolysing phosphoric acid monoesters into a phosphate ion and a molecule with a free hydroxyl group . This action is directly opposite to that of phosphorylases and kinases, which attach phosphate groups to their...
, which are inactivated by heat, are believed to be beneficial. In contrast, food scientists and FDA officials assert that most "beneficial" enzymes survive pasteurization and that humans do not use animal enzymes to metabolize nutrients.
Raw milk contains vitamin B6
Pyridoxine
Pyridoxine is one of the compounds that can be called vitamin B6, along with pyridoxal and pyridoxamine. It differs from pyridoxamine by the substituent at the '4' position. It is often used as 'pyridoxine hydrochloride'.-Chemistry:...
, but the heat treatment may cause as much as 20% of the vitamin to be lost. Pasteurization does cause the loss of several vitamin
Vitamin
A vitamin is an organic compound required as a nutrient in tiny amounts by an organism. In other words, an organic chemical compound is called a vitamin when it cannot be synthesized in sufficient quantities by an organism, and must be obtained from the diet. Thus, the term is conditional both on...
s, but only approximately 0-10%. Raw milk contains very little vitamin D
Vitamin D
Vitamin D is a group of fat-soluble secosteroids. In humans, vitamin D is unique both because it functions as a prohormone and because the body can synthesize it when sun exposure is adequate ....
, which is added to processed milk.
Protection against non-infectious disease
Two studies found a statistically significant inverse relationship between consumption of raw milk and asthmaAsthma
Asthma is the common chronic inflammatory disease of the airways characterized by variable and recurring symptoms, reversible airflow obstruction, and bronchospasm. Symptoms include wheezing, coughing, chest tightness, and shortness of breath...
and allergies.
Sensory experiences of pasteurized and un-pasteurized products
Many raw milk consumers cite a preference for the taste of raw milk products.The Raw Milk Cheesemakers Association hold that cheeses produced from raw milk have distinctive complexity and depth of flavor absent from pasteurized-milk cheeses.
The FDA considers hard, aged cheeses, such as parmesan and cheddar
Cheddar
Cheddar is a large village and civil parish in the Sedgemoor district of the English county of Somerset. It is situated on the southern edge of the Mendip Hills, north-west of Wells. The civil parish includes the hamlets of Nyland and Bradley Cross...
, made from raw milk to be generally safe for consumption; soft cheeses made from raw milk are considered unsafe. These cheeses are currently legally sold if aged for 60 days or more. Over this period, the salt
Salt
In chemistry, salts are ionic compounds that result from the neutralization reaction of an acid and a base. They are composed of cations and anions so that the product is electrically neutral...
and acid
Acid
An acid is a substance which reacts with a base. Commonly, acids can be identified as tasting sour, reacting with metals such as calcium, and bases like sodium carbonate. Aqueous acids have a pH of less than 7, where an acid of lower pH is typically stronger, and turn blue litmus paper red...
characteristics of aging cheeses generally eliminate the growth of pathogenic bacteria.
Personal choice
Raw milk advocates cite libertarianLibertarianism
Libertarianism, in the strictest sense, is the political philosophy that holds individual liberty as the basic moral principle of society. In the broadest sense, it is any political philosophy which approximates this view...
and personal choice arguments against government interference concerning the sale of raw milk. Some such advocates may feel resentment towards the government's efforts in limiting the distribution and consumption of raw milk, seeing their actions as a personal choice that is not harmful to anyone else. Raw milk activism can be associated with alternative medicine
Alternative medicine
Alternative medicine is any healing practice, "that does not fall within the realm of conventional medicine." It is based on historical or cultural traditions, rather than on scientific evidence....
and anti-regulatory activism.
Quality standards for milk
The methods of determining Grade A milk quality are well-established and outlined in the Grade A Pasteurized Milk OrdinanceGrade A Pasteurized Milk Ordinance
The Grade A Pasteurized Milk Ordinance, published by the Food and Drug Administration, outlines minimum standards and requirements for Grade A milk production and processing...
. These grades are typically related to a measurement known as the somatic cell count
Somatic cell count
Somatic cell count is an indicator of the quality of milk. Somatic cells are leukocytes . The number of somatic cells increases in response to pathogenic bacteria like Staphylococcus aureus, a cause of mastitis. The SCC is quantified as cells per ml...
(SCC) and the bacteria plate count. Generally a lower somatic cell count indicates better animal health, while the bacteria plate count indicates improved equipment sanitation.
Somatic cells originate only from inside the animal's udder
Udder
An udder is an organ formed of the mammary glands of female quadruped mammals, especially ruminants such as cattle, goats, sheep and deer. The udder is a single mass hanging beneath the animal, consisting of pairs of mammary glands...
, while bacteria are usually from external contamination, such as insufficient cleaning of the milk transport equipment or insufficient external cleansing of the cow's udder and teats prior to milking. Milking equipment can also be accidentally knocked or kicked off an animal onto the floor, and contaminants on the barn floor can be sucked into the milk line by the system vacuum. A filter sock or filter disk in the pipeline prevents large particulate contaminants from entering the milk bulk tank, but cannot remove bacterial contamination once it has occurred.
For example as defined by the State of Indiana administrative code, Grade A milk shall meet the following standards:
- The bacterial estimate classification shall be "acceptable".
- The bacteria count using the standard plate count, direct microscopic count, or plate loop count methods shall be not more than one million (1,000,000) bacteria per milliliter.
- The somatic cell count shall be not more than one million (1,000,000) cells per milliliter.
- The milk shall not contain drug residues.
Milk not meeting these standards shall be designated as undergrade. Undergrade milk may not be sold for human consumption or processing into products for human consumption.
As established, these measurements are taken daily from the milk bulk tank
Bulk tank
In dairy farming a bulk milk cooling tank is a large storage tank for cooling and holding milk at a cold temperature until it can be picked up by a milk hauler....
and not from individual cows. This is because testing of individual animals at each milking would be expensive, but it also means that milk from a sick cow is diluted and averaged down by the healthy animals. Greater bulk tanks at very great commercial farms are accommodating of more sick animals in the herd, without the sick animals affecting the overall milk quality rating.
As discussed in the paper Guidelines for Using the DHI Somatic Cell Count Program
- The results of many studies suggest that cows with SCC of less than 200,000 are not likely to be infected with major mastitis pathogens, but cows with SCC above 300,000 are probably infected (Smith, 1996).
- Herds with bulk tank SCC above 200,000 will have varying degrees of subclinical mastitis
MastitisMastitis is the inflammation of breast tissue. S. aureus is the most common etiological organism responsible, but S. epidermidis and streptococci are occasionally isolated as well.-Terminology:...
present. Data from the National Mastitis Council (1987) show that 6% of the [udder] quarters in a herd could be expected to be infected in a herd with a bulk tank SCC of 200,000.- At 500,000 SCC, 16% of the quarters may be infected with a 6% reduction in milk production compared to a SCC of 200,000.
Bacteria in milk can come from sources other than the animal. Over time the milking pipeline
Milking pipeline
A milking pipeline or milk pipeline is a component of a dairy farm animal-milking operation, which is used to transfer milk from the animals to a cooling and storage bulk tank.-Setup:...
and equipment can become coated with residues such as milkstone which are not removed by standard detergents and require periodic flushing of equipment with high strength corrosives. Automatic washing equipment for the bulk tank
Bulk tank
In dairy farming a bulk milk cooling tank is a large storage tank for cooling and holding milk at a cold temperature until it can be picked up by a milk hauler....
may not effectively clean all interior surfaces, and does not clean the exterior of the bulk tank at all.
Some buyers award producers for having the lowest SCC but this does not also lead to an increased payment for the milk quality, so there is no incentive to strive for anything more than meeting the basic grade A SCC rating.
External links
- Pasteurized and Raw Milk
- Sale/Consumption of raw Milk-Position Statement, U.S. FDA Center for Food Safety and Applied Nutrition
- Presentation on the safety of raw milk by the FDA