WHAT TO KNOW

• Pasteurization is crucial for milk safety, killing harmful germs that can cause illness.
• Consuming raw milk can lead to serious health risks, especially for certain vulnerable populations.
• Choosing pasteurized milk and dairy products is the best way to safely enjoy the nutritional benefits of milk.

Overview

Raw milk and A(H5N1) virus‎

Raw milk is milk that has not been pasteurized, a process that removes disease-causing germs by heating milk to a high enough temperature for a certain length of time. It's important to understand that raw milk can be a source of foodborne illness. While good practices on farms can reduce contamination, they cannot guarantee safety from harmful germs. Pasteurized milk offers the same nutritional benefits without the risks of raw milk consumption. Since the early 1900s, pasteurization has greatly reduced milk-borne illnesses.

Risk

• Drinking or eating products made from raw milk can expose people to germs such as Campylobacter, Cryptosporidium, E. coli, Listeria, Brucella, and Salmonella.
• Some groups, such as children under 5, adults over 65, pregnant people, and people with weakened immune systems, are at a higher risk of serious illness from these germs.

Symptoms

Symptoms of foodborne illness from raw milk can include diarrhea, stomach cramping, and vomiting. In some cases, more severe outcomes like Guillain-Barré syndrome or hemolytic uremic syndrome can occur, potentially leading to paralysis, kidney failure, stroke, or even death.

Prevention

• Choose pasteurized milk and dairy products, making sure to read labels carefully.
• Refrigerate perishable foods at 40°F or colder to slow bacterial growth. Bacteria can multiply rapidly if left at room temperature or in the “Danger Zone” between 40°F and 140°F. Never leave perishable food out for more than 2 hours (or 1 hour if exposed to temperatures above 90°F, like in a hot car or at a picnic).
• Throw away expired or spoiled food. When in doubt, throw it out.

Drinking raw milk can lead to serious illness. Raw milk is linked to many preventable foodborne illnesses and outbreaks every year. In fact, raw milk is one of the riskiest foods.

Raw Milk Has Not Been Pasteurized

Pasteurization is the process of heating milk to a high enough temperature for enough time to kill harmful germs in the milk. These germs can include bacteria such as Campylobacter, E. coli, or Salmonella; viruses; and parasites. Raw milk has not been pasteurized.

Most of the nutritional benefits of drinking raw milk are available from pasteurized milk without the risk of disease that comes with drinking raw milk.

Raw milk made into other products, like soft cheese, ice cream, and yogurt, can also cause dangerous infections. When eating these products, make sure they are made from pasteurized milk.

All Raw Milk Is Risky

The use of good hygiene practices on the farm can reduce but cannot eliminate the chance of milk getting contaminated. Healthy animals can carry germs that make people sick.

Also, testing isn’t a guarantee that raw milk is free from harmful germs. Even if testing one batch of a farm’s raw milk does not find harmful germs, the next batch can contain them. Plus, tests do not always detect low levels of contamination. Germs that go undetected in raw milk can multiply between the time the milk is tested and people drinking it.

Some People Are More at Risk of Getting Sick

Anyone, even healthy adults, can get sick from drinking raw milk, but some people are more at risk.

The people most at risk for severe illness are

• Adults 65 years and older
• Children younger than 5 years
• People with weakened immune systems

Also, raw milk and raw milk products like soft cheese can be contaminated with Listeria. Getting a Listeria infection while you are pregnant can cause miscarriage, stillbirth, or death of your newborn.

People in these groups should never consume raw milk or products made with it.

Lower Your Risk of Getting Sick

Take these steps to reduce your risk:

• Choose pasteurized milk and dairy products. Buy milk and dairy products that say “pasteurized” on the label. If in doubt, don’t buy it! Look for pasteurized milk and dairy products at farms and farmers markets.
• Refrigerate milk, dairy products, and other perishable food at 40°F or colder. Bacteria can multiply rapidly if left at room temperature or in the “Danger Zone” between 40°F and 140°F. Never leave perishable food out for more than 2 hours (or 1 hour if exposed to temperatures above 90°F, like a hot car or picnic).
• Throw away expired food, including milk and dairy products. When in doubt, throw it out.

Raw milk can contain a variety of disease-causing pathogens, as demonstrated by numerous scientific studies. These studies, along with numerous foodborne outbreaks, clearly demonstrate the risk associated with drinking raw milk. Pasteurization effectively kills raw milk pathogens without any significant impact on milk nutritional quality.

In this document, the FDA provides a close examination of the myths associated with drinking raw milk. The review below is based on scientific literature.

Raw milk does not cure lactose intolerance.

Lactose is a unique disaccharide found in milk. Lactose concentration in bovine milk is about 4.8%. People with lactose intolerance lack the enzyme, beta-galactosidase or lactase, to break down lactose into glucose and galactose during digestion. All milk, raw or pasteurized, contains lactose and can cause lactose intolerance in sensitive individuals. There is no indigenous lactase in milk.

Raw milk advocates claim that raw milk does not cause lactose intolerance because it contains lactase secreted by “beneficial” or probiotic bacteria present in raw milk. As discussed in a later section (claim 4), raw milk does not contain probiotic organisms.

Fermented dairy products, especially yogurt, have been reported to ease lactose mal-absorption in lactose intolerant subjects (McBean and Miller, 1984; Lin et al., 1991; Onwulata et al., 1989; Savaiano et al., 1984). This enhanced digestion of lactose has been attributed to the intra-intestinal hydrolysis of lactose by lactase secreted by yogurt fermentation microorganisms (Lin et al., 1991; Savaiano et al., 1984). However, raw milk does not contain the same types of microorganisms at the similar levels that are found in yogurt. Yogurt that showed a benefit towards lactose intolerance typically contained 10⁷cfu/ml or higher levels of Streptococcus thermophilus and Lactobacillus bulgaricus, and these microorganisms were purposely inoculated during yogurt manufacturing (Lin et al., 1991; Savaiano et al., 1984).

Raw milk does not cure or treat asthma and allergy.

The PARSIFAL study (Waser et al., 2007) has been misused by raw milk advocates ever since it was published. The PARSIFAL study found an inverse association of farm milk consumption, not raw milk consumption, with asthma and allergy. The authors of the PARSIFAL study clearly indicated in the paper that the “present study does not allow evaluating the effect of pasteurized vs. raw milk consumption because no objective confirmation of the raw milk status of the farm milk samples was available.” In fact, in the study, about half of the farm milk was boiled (Waser et al., 2007). The authors of the PARSIFAL study concluded that “raw milk may contain pathogens such as salmonella or EHEC, and its consumption may therefore imply serious health risks… At this stage, consumption of raw farm milk cannot be recommended as a preventive measure.” (Waser et al., 2007)

Regarding allergy, research has shown that raw milk and pasteurized milk do not differ in their anaphylactic-sensitizing capacity when tested in both animal models (Poulsen et al., 1987; McLaughlan et al., 1981) and in human clinical trials (Host and Samuelsson, 1988). Pasteurization conditions have little impact on casein structure and only cause limited whey protein denaturation. Therefore, it is not surprising that pasteurization does not change the allergenicity of milk proteins.

For example, Host and Samuelsson (1988) compared the allergic responses caused by raw, pasteurized (75°C/15 s), and homogenized/pasteurized milk in five children who are allergic to cow milk (aged 12 to 40 months). All children developed significant and similar allergic reactions from the consumption of the above three types of milk (Host and Samuelsson, 1988). The authors concluded that children with proven milk allergy can not tolerate milk, raw or pasteurized (Host and Samuelsson, 1988).

Raw milk is not more effective in preventing osteoporosis than pasteurized milk.

No scientific literature was found to substantiate the claim that pasteurized milk is linked to osteoporosis or raw milk promotes calcium deposition in bone. Studies have shown that both the concentration of calcium and its bio-availability are not affected by pasteurization (Rolls and Porter, 1973; Zurera-Cosano et al., 1994).

For example, Weeks and King (1985) showed no difference in calcium bioavailability among raw milk, homogenized HTST milk, and homogenized UHT milk in an animal study. Weanling rats were fed with the three types of milk for six to eight weeks and calcium from milk was their sole dietary calcium. Among rat groups consuming the three types of milk, there was no difference in intestinal absorption of calcium and no difference in calcium deposition in femur bone (Weeks and King, 1985). A similar conclusion was obtained in a human study using human milk. Williamson et al (1978) found no difference in the absorption and retention of calcium, phosphorous, and sodium between two groups of low birth-weight preterm infants who were fed human milk with and without heat treatment (63°C/30 min).

There are no beneficial bacteria in raw milk for gastrointestinal health.

Bacteria found in raw milk are not probiotic. Probiotic microorganisms must be non-pathogenic (Teitelbaum and Walker, 2000). In contrast, raw milk can host various human pathogens, including E. coli O157:H7, Salmonella, Streptococcus spp. Yersinia enterocolitica, Campylobacter jejuni, Staphylococcus aureus, Listeria monocytogenes, Mycobacterium tuberculosis, and Coxiella burnetti to name a few (Oliver et al., 2005; Hayes and Boor, 2001).

Probiotic microorganisms must be of human origin in order to have an impact on human health (Teitelbaum and Walker, 2000). Bacteria present in raw milk are from infected udder tissues (e.g., mastitis causing bacteria), the dairy environment (e.g., soil, water, and cow manure), and milking equipment. High bacteria counts in raw milk only indicate poor animal health and poor farm hygiene.

Bacteria in raw milk are typically not of human origin. An exception is Streptococcus pyogenes. S. pyogenes that has adapted to humans can be transmitted to animals. Once S. pyogenes is colonized in animals, it can be re-transmitted to humans as a human pathogen that causes strep throat. For example, S. pyogenes can infect a cow udder to cause mastitis. The infected cow udder can subsequently shed S. pyogenes, a pathogen, into raw milk.

Bifidobacteria have been mentioned by raw milk advocates as the “good bugs” in raw milk. Bifidobacteria are bacteria commonly found in human and animal gastrointestinal track and they are bacteria that make up the gut flora (Arunachalam, 1999). Since bifidobacteria are found in cow’s GI track, they are present in cow’s fecal matter. Raw milk collected with proper hygiene should not contain bifidobacteria. In fact, the presence of bifidobacteria in raw milk indicates fecal contamination and poor farm hygiene (Beerens et al., 2000; Beerens and Neut, 2005).

Raw milk is not an immune system building food and is particularly unsafe for children.

Children are typically more vulnerable than adults to the pathogens than can occur in raw milk. In 2005, an E. coli O157:H7 outbreak in Washington and Oregon was linked to raw milk sold in Washington state (CDC, 2007). Among the 18 patients, the 5 hospitalized were all children aged 1-13; 4 of them developed Hemolytic Uremic Syndrome (HUS) (CDC, 2007).

In September 2006 in California, two children developed HUS from drinking raw milk contaminated with E. coli O157:H7. Three weeks later, four more children acquired the same infection from raw milk or raw colostrum produced by the same dairy (CDC, 2008).

In Sep 2006, two children became sick after drinking unpasteurized milk from a licensed dairy in Washington State. The raw milk was contaminated with E. coli O157:H7. One child was hospitalized (WSDH, 2006).

In July 2008 in Connecticut, 14 people were sickened by raw milk contaminated with E. coli O157: H7. The three most seriously ill were children; two of them developed HUS (FoodHACCP.com, 2008).

In May 2008 in Missouri, four people became sick after drinking raw goat milk contaminated with E. coli O157: H7. The two severely ill were children and both were hospitalized (CDC, 2008).

In July 2010 in Colorado, eight people became sick after drinking raw goat milk contaminated with both Campylobacter and E. coli O157: H7. Two children were hospitalized (Boulder County Public Health, 2010a, b)

There are no immunoglobulins in raw milk that enhance the human immune system.

The concentration of immunoglobulins in bovine milk is low, typically about 0.6-1.0 mg/ml (Hurley, 2003). At these low concentrations, bovine immunoglobulins, when consumed directly from milk, are physiologically insignificant to humans (Fox, 2003).

The predominant fraction of immunoglobulins in bovine milk is IgG (about 85-90%). IgG is quite heat stable. In one study, LTLT pasteurization (63°C for 30 min) had no impact on the level of IgG, and HTST pasteurization (72°C/15s) resulted in only 1% denaturation of IgG (Mainer et al., 1997).

Kulczychi (1987) hypothesized that the heat-aggregated immunoglobulins may actually have better immunological function because aggregation can amplify the binding affinity of IgG to receptor sites.

There are no additional protease and lipases in raw milk that facilitate milk digestion.

Milk Proteases
Milk contains various indigenous proteases, including plasmin and somatic cell proteases (Kelly and McSweeney, 2003). The major proteolytic activity in milk is from plasmin. Plasmin is part of a complex enzyme system consisting of plasmin, plasminogen, plasminogen activator, plasmin inhibitor, and plasminogen activator inhibitor (Bastian and Brown, 1996).

The plasmin system plays important roles in milk quality and cheese ripening (Bastian and Brown, 1996). Increase in plasmin activity is often reported in low quality milk with high somatic cell counts (Ma et al., 2000; Kelly and McSweeney, 2003; Bastian and Brown, 1996). High plasmin activity in fresh milk reduces milk shelf-life due to the hydrolysis of milk casein and the production of bitter peptides. High residual plasmin activity in shelf-stable UHT milk has also been associated with age gelation, a product defect.

Plasmin is heat stable and large percentage of this enzyme survives pasteurization (Bastian and Brown, 1996; Richardson, 1993). Even after UHT treatment, 30-40% of the plasmin activity can still remain (Alichanidis et al., 1986).

Proteases of somatic cell origin become significant when cows are infected with mastitis (Verdi et al., 1987). Milk from mastitic cows is of low quality and is more likely to contain pathogens. The most prevalent mastitis causing organisms in dairy herds are E. coli, Staphylococci, and Streptococci (Hayes and Boor, 2001; Wilson et al., 1997). Mastitic cows can also shed other pathogens into raw milk, including L. monocytogenes (Schoder et al., 2003; Pearson and Marth, 1990; Jensen et al., 1996), Salmonella (Wood et al., 1991), and Coxiella burnetti (Barlow et al., 2008).

Milk can also contain exogenous proteases secreted from bacteria growing in milk. Proteases of microbial origin become significant when bacterial counts exceed 10⁶-10⁷cfu/ml (Cousin, 1982). Therefore, any significant amount of protease of bacterial origin in raw milk only indicates that the raw milk is heavily contaminated. Heavily contaminated raw milk is more likely to contain pathogens.

There is no reported physiological role of milk indigenous or exogenous proteases in human protein digestion. These enzymes, like other proteins, are denatured in the acid gastric environment and digested by human proteases secreted in the gastrointestinal track.

Lipase
The main indigenous lipase in bovine milk is lipoprotein lipase (LPL). Other types of lipases that may present in milk are lipases from somatic cells and lipase secreted from microorganisms growing in raw milk under unsanitary conditions (Weihrauch, 1988). Lipases from somatic cells only become significant when the cow is infected with mastitis, and milk from mastitic cows is more likely to contain pathogens. Milk also contains several esterases. The concentrations of milk esterases are very low compared to LPL, and unlike LPL, milk esterases hydrolyze ester substrates in solution rather in an emulsified form (Deeth and Fitz-Gerald, 1995).

There is no physiological role of LPL in milk lipid digestion or utilization (Olivecrona et al., 2003; Weihrauch, 1988). Therefore, even though pasteurization does inactivate most of LPL activity (Shipe and Senyk, 1981), such effect has no impact on the nutritional values of milk. In fact, it is desirable to completely inactivate LPL since any residual LPL activity can cause the development of rancid off-flavor, a serious quality defect in milk (Shipe and Senyk, 1981). Gastric lipase and pancreatic lipase secreted in the human gastrointestinal track are responsible for the digestion of lipids (Gurr, 1995; Jensen and Jensen, 1992).

In human milk, there is another lipase called bile-salt stimulated lipase (BSSL). This enzyme can substantially improve the utilization of human milk lipids, particularly in premature infants (Andersson et al., 2007; Jensen and Jensen, 1992; Olivecrona et al., 2003; Williamson et al., 1978). However, BSSL is not present in bovine milk (Olivecrona et al., 2003).

Raw milk is not nutritionally superior to pasteurized milk.

Numerous studies have indicated that pasteurization has minimal impact on milk nutritional quality.

Milk proteins
Normal bovine milk contains about 3 to 3.5% total protein. The two major groups of milk protein are casein (about 80%) and whey proteins (about 20%). The protein quality of pasteurized milk is not different from that of raw milk (Andersson and Oste, 1995).

Using in vitro method, Carbonaro et al (1996) found no difference in protein digestibility between raw milk (80.2%), milk pasteurized at 75°C/15s (80.02%), and milk pasteurized at 80°C/15s (80.3%).

In an animal study (weaning Holtzman male rats), Efigenia et al (1997) evaluated the nutritional quality of bovine milk after pasteurization. After a study period of 28 days, there was no difference in animal weight gain, food intake, food efficiency ration, protein efficiency ratio, or apparent protein digestibility between the rat group that consumed raw bovine milk and the group that consumed pasteurized bovine milk (Efigenia et al., 1997).

Similar results were obtained in another animal study by Lacroix et al (2006). In this study, no difference in protein digestibility was observed between milk protein without heat treatment and the same protein heated at 72°C/20s or 96°C/5s (Lacroix et al., 2006).

In a recent human study, Lacroix et al (2008) evaluated the impact of heat treatment on protein quality by studying dietary nitrogen metabolism following a single meal. Human subjects were fed a meal formulated with milk protein with or without HTST pasteurization (72°C/20s). The same metabolic utilization of milk protein nitrogen was observed for both raw and pasteurized milk (Lacroix et al, 2008).

Milk fat and the effect of homogenization
Typical bovine milk contains about 3 to 4% milk fat, with 97.5% of the fat existing as triglycerides (Christie, 1995). Pasteurization has essentially no effect on milk fat composition (Rolls and Porter, 1973); and for that reason, research on this topic is minimal.

Work has been done on the effect of pasteurization on human milk fat. No change was observed in total fat content and fatty acid composition (saturated, monounsaturated, polyunsaturated) of human milk after pasteurization (62.5°C for 30 min) (Fidler et al., 2001). Even after heating pooled human milk for 100°C/5 min, no change in milk fatty acid composition (including polyunsaturated long chain fatty acids) was observed (Romeu-Nadal et al., 2008).

Commercial milk is typically homogenized to increase physical stability, i.e. to prevent gravity separation of fat. Milk fat globules are reduced in size from 3 to 10 micron to less than 2 micron in diameter after typical homogenization (Swaisgood, 1985). The native fat globules are covered by the milk fat globule membrane (MFGM). After homogenization, casein and whey protein cover and stabilize the newly reformed fat globules.

The effect of homogenization on milk nutrition has been reviewed (Michalski, 2007; Michalski and Januel, 2006). It is concluded that “regarding human nutrition, homogenized milk seems more digestible than untreated milk.” (Michalski and Januel, 2006) People with lactose intolerance or milk allergy show similar response to non-homogenized and homogenized milk (Michalski, 2007; Michalski and Januel, 2006). Research is ongoing to determine whether there is any other physiological impact of homogenization on human nutrition. In one aspect, it is suggested that since homogenization releases milk fat globule membrane components, the functions of some of the bioactive components in MFGM may be enhanced (Michalski and Januel, 2006).

Milk minerals
Minerals are stable under pasteurization conditions and there is minimal change in their concentrations after pasteurization (Rolls and Porter 1973). Both in vitro and in vivo studies demonstrate that there is no impact of pasteurization on milk mineral content and mineral bioavailability (Van Dael et al.,1993; Weeks and King, 1985; Zurera-Cosano et al., 1994).

As discussed in a previous section (claim 3), the concentration and bioavailability of calcium, the most nutritionally important mineral in milk, is the same in raw and pasteurized milk. In another study, Van Dael et al (1993) demonstrated using in vitro method that the bioavailability of zinc and selenium in milk was not affected by pasteurization (73°C/15s) or sterilization (110°C/10 min).

Milk vitamins
Milk contains both fat soluble and water soluble vitamins. Fat soluble vitamins include A, D, E, and K. Water soluble vitamins included B1 (thiamin), B2 (riboflavin), niacin, pantothenic acid, B6, biotin, folic acid, B12, and vitamin C (Renner et al., 1989). In general, pasteurization has a little effect on milk vitamin levels (Bendicho et al., 2002; Renner et al., 1989). Vitamins that are present at high levels in milk, such as riboflavin, B6 and B12, are relatively heat stable. Other factors, such as storage temperature, dissolved oxygen, light exposure, packaging, and length of storage can have a much greater impact on milk vitamin stability (Gaylord et al., 1986; Kon, 1972; Lavigne et al., 1989; Pizzoferrato, 1992; Renner et al., 1989; Scott et al., 1984a; Scott et al., 1984b).

The only vitamin that is significantly heat labile is vitamin C but milk is an insignificant source for vitamin C. A cup of milk (240 ml) only provides about 5 mg of vitamin C (Renner et al., 1989).

Vitamin C is very susceptible to oxidation. Sample to sample variation can be considerable (Scott et al., 1984a) and degradation can happen immediately after milking due to photo-oxidation (Kon, 1972; Renner et al., 1989; Scott et al., 1984a). Reported values of vitamin C vary depending on seasonality, storage temperature, and elapsed time before analysis.

Lavigne et al (1989) reported that HTST at 72°C/16s reduced vitamin C in goat milk by 5%. Haddad and Loewenstein (1983) observed vitamin C level of 23.3 mg/liter in raw milk. After pasteurization at 72°C/16s, vitamin C was reduced by 16.6%. Similarly, Head and Hansen (1979) reported that in whole milk, vitamin C was reduced about 15% (from 24.3 mg/liter to 20.7 mg/liter) after pasteurization.

The loss of vitamin C increases with heating temperature and time and fits the first order kinetic model (Bendocho et al., 2002; Haddad and Loewenstein, 1983). Substantial loss only occurred after very high temperature heating for long time. For example, heating at 90°C for 10 min can cause 70% reduction in vitamin C (Bendicho et al., 2002).

Interestingly, Pizzoferrato (1992) indicated that vitamin C retention during storage is better in heated milk (72°C/15s, 75°C/15s, 80°C/15s) than in raw milk. The better retention was due to the removal of oxygen and the inactivation of peroxidase and microorganisms during heat treatment (Pizzoferrato, 1992).

Raw milk does not contain natural antimicrobial components that make milk safe.

The major antimicrobial compounds naturally present in milk include lactoferrin, lactoperoxidase, lysozyme, and xanthine oxidase. There is no scientific evidence to support the claim that the indigenous antimicrobial compounds in raw milk kill pathogens and ensure raw milk safety.

Raw milk does not contain high enough concentration of these antimicrobial compounds to exert such an effect. In the case of lysozyme and lactoferrin, if high concentrations of these components are observed in raw milk, it is often an indication of cow’s compromised health condition (e.g. mastitis), simply due to cow’s elevated natural defense system (Chaneton et al., 2008; Schmitz et al., 2004; Farkye, 2003).

The microflora in raw milk is complex and unpredictable. The antimicrobial components in milk can have either bactericidal, bacteriostatic, or no effect at all depending on the specific pathogenic species and strains involved (Naidu, 2000a).

Pasteurization is the only method to achieve complete elimination of vegetative pathogens. Contrary to raw milk advocates’ claims, pasteurization does not completely inactive these indigenous antimicrobial components in milk.

Lactoferrin
The doses of lactoferrin required to have bactericidal or bacteriostatic effect are in the range of 1 to 8 g/L (Naidu, 2000b). The substantially lower concentration of LF in mature bovine milk, about 0.1 g/L, is simply too low to have an effect (Naidu, 2000b).

Commercial pasteurization causes no significant loss of LF antimicrobial activity (Paulsson et al., 1993; Sanchez et al., 1992). Retention of LF is estimated to be 97-99% after heating at 72°C for 15s and 87-95% after heating at 85°C for 15s (Sanchez et al., 1992). Purified lactoferrin solution (0.5 to 1 g/L) with and without heat treatment (62.8°C for 30 min, 72°C for 15s, or 72°C for 10 min) showed the same antimicrobial effects towards E. coli O157:H7, Salmonella enteritidis, and Listeria monocytogenes (Conesa et al., 2010)

Lysozyme
he concentration of lysozyme in bovine milk is very low ( 0.3 mg/100 ml), much lower than the level in human milk (10 mg/100 ml) (Renner et al., 1989; Silanikove et al., 2006). When cows are infected with mastitis, lysozyme level increases in milk (Farkye, 2003). Lysozyme is relatively heat stable (Griffiths, 1986). Heat at 82.2°C for 15s, a condition much severer than HTST, only reduces enzyme activity by 6.3% (Griffiths, 1986).

Lactoperoxidase (LP)
The term lactoperoxidase system (LP-s) refers to the integral system of lactoperoxidase, thiocyanate, and hydrogen peroxide. To be effective as an antimicrobial system in raw milk, lactoperoxidase needs to be activated by the addition of thiocyanate (SCN-) and a source of hydrogen peroxide (H₂O₂) to milk (Arques et al., 2008; Björck 1978; Björck et al., 1978; Rodríguez et al., 1997).

CODEX allows the use of activated LP-s to prevent spoilage during collection and transportation of raw milk when adequate refrigeration is not available (Codex CAC/GL 13-1991). Typically, per liter of milk, LP-s can be activated by the addition of 14 mg of sodium thiocyanate (equivalent to 10 ppm thiocyanate) and 30 mg of sodium percarbonate (equivalent to 8.5 ppm hydrogen peroxide) (FDO/WHO, 2005; Codex CAC/GL 13-1991). The addition of thiocyanate increases its overall level from about 5 ppm naturally present in milk to 15 ppm. FAO/WHO clearly states that the purpose of LP-s is “not to render milk safer for consumption” and that “the safety of milk is only achieved through a combination of good hygienic practices and heat treatment of milk, independent of LP-s.” (FAO/WHO, 2005)

Xanthine oxidase (XO)
Xanthine oxidase is a well-know enzyme found on milk fat globule membrane (MFGM) (Farkye, 2003; Harrison, 2006). XO is a non specific oxido-reductase involved in purine catabolism, catalyzing the oxidation of hypoxanthine to xanthine and of xanthine to uric acid (Farkey, 2003; Harrison, 2006).

The antimicrobial role of XO is centered on XO’s ability to catalyze reactions that generates reactive oxygen species (e.g. superoxides and hydrogen peroxide) and reactive nitrogen species (e.g. nitric oxide and peroxynitrite) (Stevens, et al., 2000; Vorbach et al., 2003; Martin et al., 2004: Harrison, 2006). These highly reactive species are bactericidal or bacteriostatic. It has also been hypothesized that antimicrobial effect is derived from the formed hydrogen peroxide that participate in the lactoperoxidase system. However, the exact mechanisms involved in the antimicrobial phenomena are still “unclear and undoubtedly complex” (Harrison, 2006). The FDA is not aware of any publication that studied pathogen reduction by inherent levels of XO present in raw milk.

A paper published by Oster in 1971 postulated that XO absorbed onto homogenized milk fat droplets can cause tissue damage and initiate atherosclerotic process (Oster, 1971). However, additional research refuted this hypothesis (Clifford, et al., 2003).

Griffiths (1986) reported a D value of 303.8 s at 75°C for XO. This means that XO activity will be reduced by 10% after heat treatment at 75°C for 15s. Andrews et al. (1987) indicated that XO is the most heat stable milk fat globule membrane enzyme and less than 10% of its activity is lost after heat treatment at 80°C for 15s (Andrews, et al., 1987).

Raw milk does not contain nisin for pathogen inhibition.

Nisin is a small heat stable antimicrobial peptide produced by certain strains of Lactococcus lactis subsp. lactis (Arauz et al., 2009; Thomas et al., 2000). Raw milk advocates claim that indigenous microflora of raw milk produces nisin that kills pathogens. There is no scientific basis for such claim.

Nisin is only produced during the exponential growth phase of Lactococcus organisms (Arauz et al., 2009; Thomas et al., 2000) and these organisms do not grow well at refrigeration temperatures. Any substantial nisin production in raw milk will only suggest poor hygiene and poor refrigeration. Therefore, even if raw milk contained nisin-producing Lactococcus, the amount of nisin present in raw milk would be negligible.

Nisin is effective against gram-positive bacteria including strains of Lactococcus, Streptococcus, Staphylococcus, Micrococcus, Pediococcus, Lactobacillus, Listeria, and Mycobacterium (Arauz et al., 2009; Sahl et al., 1995). Nisin is generally not effective against gram-negative bacteria, fungi, and virus (Arauz et al., 2009; Boziaris and Adams 1999). Important milkborne pathogens such as Salmonella, Campylobacter jejuni, E. coli O157:H7, and Yersinia enterocolitica are gram negative and thus are not affected by nisin (Arauz et al., 2009).

Folate binding protein (FBP) is not denatured during pasteurization and folate utilization is not reduced in pasteurized milk.

The concentration of folate in milk is low, about 5 -8μg/100g (Renner et al., 1989; Andersson and Oste, 1994). Dietary reference intake for folate is 400 μg per day for male 19-30 years of age (http://iom.edu/~/media/Files/Activity%20Files/Nutrition/DRIs/DRI_Vitamins.pdf). Milk is not a folate rich food.

Pasteurization has a limited impact on milk folate level. Folate remains bound to folate binding protein (FBP) after pasteurization (Wigertz et al., 1996). Andersson and Oste (1994) observed no change in milk folate content after pasteurization at 75°C for 16s. Wigertz and Jägerstad (1993) reported a slight decrease of folate content from 8μg/100 g to 6.4μg/100g after pasteurization at 74°C for 15s.

Studies have shown some decrease in the concentration of folate binding protein (FBP) after pasteurization but the decrease is typically small and a substantial amount of residual FBP is still present in the pasteurized milk. For example, Wigertz et al (1996) observed a FBP concentration of 211± 7 nmol/l in raw milk. After pasteruzation (74°C/15s), FBP concentration was about 168 ± 20 nmol/l (Wigertz et al, 1996). In a separate study, Wigertz and Jägerstad (1993) found no difference in FBP concentration before and after pasteurization (74°C/15s).

Pasteurized milk is safer than raw milk.

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Outbreaks due to raw milk and raw milk products continue to occur each year. In 2010 alone, raw milk has been associated with at least 8 documented outbreaks:

• New York, Campylobacter outbreak, 5 illnesses (New York Department of Health, 2010)
• Michigan, Campylobacter outbreak, 12 illnesses (FDA, 2010)
• Pennsylvania, Campylobacter outbreak, 10 illnesses (PRNewswire, 2010)
• Utah, Campylobacter outbreak, 9 illnesses (Utah Department of Health, 2010)
• Utah, Salmonella outbreak, 6 illnesses (Utah Department of Health, 2010)
• Minnesota, E. Coli O157:H7 outbreak, 8 illnesses and 4 hospitalizations (Minnesota Department of Health, 2010)
• Washington, E. Coli O157:H7 outbreak, 8 illnesses (Washington State Department of Health, 2010)
• Colorado, Campylobacter and E. Coli O157:H7 outbreak, 30 illnesses, 2 hospitalizations (Boulder County Public Health, 2010a, b)

Based on CDC data, literature, and state and local reports, FDA compiled a list of outbreaks that occurred from 1987 to September 2010 in the US. During this period, there were at least 133 outbreaks due to the consumption of raw milk and raw milk products. These outbreaks caused 2,659 cases of illnesses, 269 hospitalizations, 3 deaths, 6 stillbirths and 2 miscarriages. The numbers of outbreaks and illness cases were likely higher than the above estimates due to underreporting.

Of the 133 outbreaks occurring from 1987 to September 2010, 5 were multistate outbreaks with cases from at least two states. The remaining 128 outbreaks occurred in 30 states. Of these 30 states, 20 allowed some type or raw milk sale for direct human consumption according to the National Association of State Departments of Agriculture survey of 2008 (NASDA, 2008). Outbreaks from these 20 states accounted for 80% of all outbreaks in the US during this period. The three states that had the highest frequencies of outbreaks are California, Washington, and Utah, accounting for about 12%, 12%, and 8% of all outbreaks, respectively.

Raw milk causes a greater rate of foodborne outbreaks than pasteurized milk.

In The Verbal Argument by Mark McAfee, the author cited various foodborne outbreaks where pasteurized milk was implicated. For these cited outbreaks, FDA was able to find scientific literature describing these outbreaks. In most cases, the implicated milk was contaminated post-pasteurization. Ironically, in many cases, the actual source of contamination was raw milk (Tacket et al., 1984; CDC, 1984; Fleming et al., 1985; Ryan et al., 1985; Linnan, et al., 1988; Olsen, et al., 2004).

1976 Yersinia enterocolitica outbreak in pasteurized chocolate milk

(Reference: Black, R. E., R. J. Jackson, T. Tsai, M. Medvesky, M. Shayegani, J. C. Feeley, K. I. E. MacLeod, and A. H. Wakelee. 1978. Epidemic Yersinia enterocolitica Infection Due to Contaminated Chocolate Milk. New England Journal of Medicine. 298:76-79.)

Pathogenic bacteria were likely introduced during hand mixing of chocolate syrup with previously pasteurized milk. No further heat treatment was applied after hand mixing.

1982 Yersinia enterocolitica outbreak from milk produced in Memphis TN

(Reference: Tacket, C. O., J. P. Narain, R. Sattin, J. P. Lofgren, C. Jr. Konigsbery, R. C. Rendtorff, A. Rausa, B. R. Davis, and M. L. Cohen. 1984. Multistate outbreak of infections caused by Yersinia enterocolitica transmitted by pasteurized milk. Journal of the American Medical Association. 251:483-486.)

The exact mechanism of contamination was not clear. However, it was suggested that even though typical pasteurization kills Y. enterocolitica, if the level of Yersinia contamination is very high in raw milk, a small amount of pathogen might have survived pasteurization.

1983 Listeria monocytogenes outbreak in MA

(Reference: Fleming, D., S. L. Cochi, K. L. MacDonald, J. Brondum, P. S. Hayes, B. D. Plikaytis, M. B. Holmes, A. Audrier, C. V. Broome, and A. L. Reingold. 1985. Pasteurized Milk as a Vehicle of Infection in an Outbreak of Listeriosis. New England Journal of Medicine. 31:404-407.)

The likely cause of this outbreak was the high levels of L. monocytogenes contamination in the starting raw milk. During the outbreak period, raw milk was sourced from farms that had dairy cows infected with listeriosis. In addition, multiple serotypes of L. monocytogenes were isolated from raw milk obtained from these farms after the outbreak.

1984 Salmonella Typhimurium outbreak in Kentucky

(Reference: CDC. 1984. Salmonellosis from Inadequately Pasteurized Milk – Kentucky. 1984. Morbidity and Mortality Weekly Report. 33:505-506.)

The outbreak was linked to milk that was under-pasteurized. The plant that produced contaminated milk did not have proper time-temperature recording and frequently did not meet the minimum PMO defined pasteurization conditions. Therefore, Salmonella Typhimurium that was present in raw milk was not adequately destroyed.

1985 Listeria monocytogenes outbreak in cheese in Los Angeles, CA

(Reference: Linnan, M. J., L. Mascola, X. D. Lou, V. Goulet, S. Mary, C. Salminen, D. W. Hird, M. L. Yonekura, P. Hayes, R. Weaver, A. Audurier, B. D. Plikaytis, S. L. Fannin, A. Kleks, and C. Broome. 1988. Epidemic Listeriosis Associated with Mexican-Style Cheese. New England Journal of Medicine. 319:823-828.)

The outbreak was linked to branded Mexican-style cheeses. The cheese produced in the implicated plant was frequently contaminated with raw milk. During inspection, 9 out of 80 cheese samples tested were positive for alkaline phosphatase, indicating that the milk was not pasteurized or improperly pasteurized. On several occasions, 10% or more raw milk might have mixed in with pasteurized milk prior to cheese making.

1984 and 1985 two Salmonella Typhimurium outbreaks traced back to pasteurized 2% milk produced in an IL plant

(Reference: Ryan, C. A., M. K. Nichels, N. T. Hargrett-Bean, M. E. Potter, T. Endo, L. Mayer, C. W. Langkop, C. Gibson, R. C. McDonald, R. T. Kenney, N. D. Puhr, P. J. McDonnell, R. J. Martin, M. L. Cohen, and P. A. Blake. 1987. Massive Outbreak of Antimicrobial-Resistant Salmonellosis Traced to Pasteurized Milk. JAMA. 258:3274.)

The 2% pasteurized milk was likely contaminated by raw milk post-pasteurization. Both the FDA lab and a private lab confirmed that the outbreak strain of Salmonella was heat sensitive and would not survive pasteurization. The implicated plant had an unusual setup of its processing line: pasteurization was an early step followed by separation and fat standardization. Investigation at the implicated plant revealed a potential cross-connection between tanks that contained raw milk and pasteurized skim milk.

1993-1994 Salmonella enteritidis in pasteurized ice cream in MN, SD

(Reference: Hennessy, T. W., C. W. Hedberg, L. Slutsker, K. E. White, J. M. Besser-Wiek, M. E. Moen, J. Feldman, W. W. Coleman, L. M. Edmonson, K. L. MacDonald, and M. T. Osterholm. 1996. A national outbreak of Salmonella enteritidis infections from ice cream. The Investigation Team. New England Journal of Medicine. 334:1281-1286.)

Outbreak investigators concluded that the ice cream premix was most likely contaminated during transport in a tanker trailer that had previously carried non-pasteurized liquid eggs contaminated with S. enteritidis.

1995 Yersinia enterocolitica outbreak due to post-pasteurization contamination

(Reference: Ackers, M. L., S. Schoenfeld, J. Markman, M. G. Smith, M. A. Nicholson, W. DeWitt, D. N. Cameron, P. M. Griffin, and L. Slutsker. 2000. An outbreak of Yersinia enterocolitica O:8 infections associated with pasteurized milk. Journal of Infectious Disease. 181:1834-1837.)

The outbreak occurred in Vermont and New Hampshire. The implicated milk was likely contaminated post pasteurization when it was filled into milk bottles rinsed by untreated well-water. Well water had high coliform counts, which suggested possible fecal contamination and possible Y. enterocolitica contamination by pigs on the dairy farm. Y. enterocolitica was isolated from 1 raw milk sample and 1 fecal sample from a pig on the dairy farm.

2000 Salmonella Typhimurium outbreak in PA and NJ

(Reference: Olsen, S. J., M. Ying, M. F. Davis, M. Deasy, B. Holland, L. Lampietro, M. Baysinger, F. Sassano, L. D. Polk, B. Gormley, M. J. Hung, K. Pilot, M. Orsini, S. van Duyne, S. Rankin, C. Genese, E. A. Bresnitz, J. Smucker, M. Moll, and J. Sobel. 2004. Multidrug-resistant Salmonella Typhimurium infection from milk contaminated after pasteurization. Emerging Infectious Diseases. 10:932-935.)

Outbreak investigation indicated that the milk processing plant had several violations of sanitary standards that could have resulted in the contamination of milk after pasteurization. These violations included excess condensation and high humidity in processing areas, leakage of raw milk onto plant floor, and storage of raw milk at > 10°C. Contamination might have originated from Salmonella-contaminated raw milk since “two dairy cow isolates of S. Typhimurium obtained during the outbreak period were outbreak related strains.”

2006 Campylobacter jejuni outbreak in CA prison

(Reference: Yuan, J. W., Jay, M. T., Barry, P., Schneider, J., Beam, S., Kanan, R., Mandrell, R., Miller, W., Winslow, D., and Mohle-Boetani, J. 2007. Campylobacteriosis Outbreak Associated with Pasteurized Milk — California, May 2006 . Available at http://www.cdc.gov/eis/downloads/2007.EIS.Conference.pdf. Accessed 11-4-2010.)

During investigation, it was noted that pasteurized milk produced before the outbreak had high bacteria counts. In addition, about 100 different C. jejuni strains were isolated on the dairy farm with 3 isolates matching the human illness strain. These observations suggested that either the starting raw milk had very high levels of pathogen contamination from the dairy environment or the milk was contaminated post pasteurization.

2007 L. monocytogenes outbreak in MA

(Reference: CDC. 2008. Outbreak of Listeria monocytogenes infections associated with pasteurized milk from a local dairy – Massachusetts, 2007. Morbidity and Mortality Weekly Report. 57:1097-1100.)

The pasteurized milk was most likely contaminated post pasteurization. The dairy plant had poor sanitation practices and several environmental samples obtained at the plant were positive for L. monocytogenes.

Raw milk produced under HACCP does not make it safe to drink.

FDA does not believe that HACCP can ensure raw milk safety. The sanitary procedures described in a food safety plan under HACCP might help to reduce the probability of raw milk contamination but they will not ensure that raw milk is pathogen-free.

As the preceding discussion demonstrates, raw milk does not naturally kill pathogens of concern. Further, testing raw milk for the various pathogens prior to consumption can not be used as an alternative to pasteurization. The potential pathogens present in raw milk can be diverse, variable, and unpredictable. It is simply impossible to test every single batch of raw milk for every single pathogen prior to human consumption. More importantly, the inability of a method to detect pathogens does not indicate the absence of pathogens (Oliver et al., 2009).

There is no visual or sensory indicator for the presence of pathogen. Typical milk quality indicators, such as standard plate counts and somatic cell counts, do not provide information on the presence or absence of pathogens. Seemingly high quality raw milk based on these routine quality indicators can still contain pathogen (Van Kessel et al., 2008). In the Federal Register notification for the final rule to 21 CFR Part 1240.61, FDA made a number of findings including the following:

"It has not been shown to be feasible to perform routine bacteriological tests on the raw milk itself to determine the presence or absence of all pathogens and thereby ensure that it is free of infectious organisms."

HACCP ensures product safety through process control and not by finished product testing. HACCP has been considered possible for chemical and physical hazard controls in farm settings. However, HACCP is not effective or even possible in farm settings for biological hazards, including pathogens (Cullor, 1997; Sperber, 2005). Cullor (1997) indicated that potential biological hazards that may exist on the dairy farms do not have well-known critical control points. Since establishing critical control points is one of the most important aspects of HACCP, without well-known critical control points, HACCP simply does not work for pathogen control for raw milk production on the farm.

Organic Pastures is an example of a raw milk producer with a HACCP plan whose milk has been found to contain pathogens. In 2007, raw cream from Organic Pastures was found to be contaminated with Listeria monocytogenes (FDA, 2007). In 2006, raw milk contaminated with E. coli O157:H7 from Organic Pastures was implicated in an outbreak that resulted in 6 illnesses and 3 hospitalizations (CDC, 2008). The median age of this outbreak’s victims was 8 years (range: 6- 18 years) (CDC, 2008).

Summary

None of the claims made by the raw milk advocates that we have examined for you can withstand scientific scrutiny. Unfortunately, the false “health benefits” claims of raw milk advocates may cause parents to give raw milk to their children and prompt immuno-compromised people, such as pregnant women, the elderly, and hospitalized patients, who want better nutrition, to also start consuming raw milk. It is these very same sub-groups of the population, however, that are most at risk for becoming ill or even dying from foodborne illness as a result of consuming adulterated raw milk.

Aren’t raw or natural foods better than processed foods?

Many people believe that foods with little to no processing are better for their health. Many people also believe that small, local farms are better sources of healthy food. However, some types of processing are needed to protect health. One type of processing happens when we cook raw meat, chicken and other poultry, and fish to make them safe to eat. Similarly, when milk is pasteurized, it is made safe by heating it at a high enough temperature for long enough to kill disease-causing germs. Most nutrients remain in milk after it is pasteurized.

Is raw milk a good source of beneficial bacteria?

Raw milk contains bacteria, and some of them can be harmful. If you’re thinking about consuming raw milk because you believe it is a good source of beneficial bacteria, keep in mind that you may instead get sick from the harmful bacteria. If you think that certain types of bacteria may be beneficial to your health, consider getting them from foods that don’t involve such a high risk.

I know people who have been drinking raw milk for years, and they never got sick. Why is that?

The presence of germs in raw milk is unpredictable. People can drink it for a long time without getting sick, and then get sick if their milk is contaminated.

What are the risks associated with drinking raw milk?

Raw milk is milk that has not been pasteurized to kill harmful bacteria. Raw milk can be contaminated with harmful germs that can make you very sick. In fact, raw milk is one of the riskiest foods.

People who get sick from raw milk might have many days of diarrhea, stomach cramping, and vomiting. Some people might develop severe or even life-threatening diseases, including:

• Guillain-Barré syndrome, which can cause paralysis, and
• Hemolytic uremic syndrome, which can result in kidney failure, stroke, and even death.

Here are some things you should know:

• Raw milk is linked to a variety of foodborne illnesses. Some of these illnesses can be severe.
  • Symptoms of foodborne illness depend on the germ swallowed.
• People can get ill from the same brand and source of raw milk that they drank previously, even for a long time, without becoming ill.
• Pasteurizing milk reduces the chance of illness. Pasteurization is the process of heating milk to a high enough temperature for enough time to kill harmful germs in the milk.
• Raw milk can get contaminated many ways. Healthy animals can carry germs that are harmful to people. Germs in these animals’ poop can get into raw milk and contaminate it.
• Good safety practices can reduce the chance of germs getting in raw milk, but not completely eliminate it.

Who is at greatest risk of getting sick from drinking raw milk?

People most at risk for severe foodborne illness are adults 65 years and older, children younger than 5 years, and people with weakened immune systems. But healthy people of any age can get very sick after drinking raw milk contaminated with harmful germs.

Can drinking raw milk hurt me or my family?

Yes. Raw milk and products made from raw milk, including soft cheese, ice cream, and yogurt, can be contaminated with germs that can cause serious illness, hospitalization, or death. Make the best decision for your health and the health of your family by always choosing pasteurized milk and products made with it. If you or your family member have consumed raw milk and get sick, seek medical attention immediately.

What is pasteurization, and what is pasteurized milk?

Pasteurization is the process of heating milk to a high enough temperature for a long enough time to kill harmful germs. Pasteurized milk is milk that has gone through this process.

What is the history of pasteurization in the United States?

Pasteurization was invented during a time when millions of people became sick and died of tuberculosis, scarlet fever, typhoid fever, and other diseases that were spread through raw milk.

Routine pasteurization of milk began in the United States in the 1920s and became widespread by 1950 as a way to reduce contamination and reduce human illnesses. It led to dramatic reductions in the number of people getting sick. Most public health professionals and health care providers consider pasteurization to be one of public health’s most effective food safety interventions ever!

Many medical and scientific organizations recommend pasteurization for all milk consumed by humans; these organizations include CDC, the U.S. Food and Drug Administration, the American Academy of Pediatrics, the American Veterinary Medical Association, the National Association of State Public Health Veterinarians, and others.

Does pasteurization change milk’s nutritional benefits?

Most of the nutritional benefits of drinking milk are available from pasteurized milk without the risk of disease that comes with drinking raw milk.

Is it true that raw milk has more enzymes and nutrients than pasteurized milk?

Multiple studies have shown that pasteurization does not significantly affect the nutritional quality of milk. Scientists do not have any evidence that shows a nutritional benefit from drinking raw milk.

Has pasteurized milk ever been linked to illnesses or outbreaks?

Pasteurized milk and products made from it have occasionally caused illnesses and outbreaks. Usually, this has happened because germs got in the milk or milk product after the milk was pasteurized.

Pasteurized milk is very unlikely to contain harmful germs if it is

• correctly handled in the dairy,
• bottled, sealed, and refrigerated after pasteurization, and
• properly handled by the consumer, including refrigerating it at 40°F or colder.

Considering the large amount of pasteurized milk that people drink, illness from it is very rare.

How does milk get contaminated?

Milk can get contaminated in these ways:

• Germs from an animal’s poop can get in milk
• Germs from an animal’s skin can get in milk
• Germs in the environment (including the barn and milking equipment) can get in milk
• The dairy animal’s udder can be infected (mastitis)
• The dairy animal can have a disease (for example, bovine tuberculosis)
• Insects, rodents, and other small animals can get in milk
• Conditions in the milk processing plant can be unsanitary
• Cross-contamination from dairy workers can happen—for example, through contact with dirty clothing or boots

Pasteurization can kill germs in milk that can make people very sick.

Does milk have a “built-in” safety mechanism that prevents bacterial contamination?

No. Pasteurization is the best way to get rid of harmful germs in milk and the only method regularly used in the United States.

My farmer tests raw milk, so isn’t it safe?

No. Negative laboratory tests to detect germs in raw milk do not guarantee that raw milk is safe to drink. Tests do not always detect low levels of contamination. People have become very sick from drinking raw milk that came from farms that regularly tested their milk for bacteria.

My farmer uses grass-fed cows and goats to produce raw milk, so isn’t it safe?

No. Outbreaks of illness linked to raw milk have been traced back to both grass-fed and grain-fed animals.

My farmer’s raw milk is organic, so isn’t it safe?

No. Raw milk, regardless of whether it is organic, can contain harmful germs. Pasteurized organic milk is available in many places, including supermarkets, farmers’ markets, and dairies.

Is raw milk at the farmers market safe?

No. No raw milk is safe. Look for pasteurized milk at farmers markets and farm stands.

I’ve heard that many organic and raw milk producers are creating sanitary conditions for raising and milking animals. Does this help reduce milk contamination?

Following good hygiene practices on the farm and during milking can reduce the chance of milk contamination – but not eliminate it.

Illness-causing germs thrive in the environment of dairy farms, even if the farm or barns are kept clean and the farmers are careful when milking. Farmers cannot guarantee that their raw milk and the products made from it are free of harmful germs, even if tests indicate the raw milk does not contain harmful germs.

Can I still get a disease from raw milk and raw milk products if the animals are healthy, clean, and grass-fed or if the dairy is careful and clean when collecting the milk?

Yes. Even healthy animals may carry germs that can contaminate milk. Small numbers of bacteria can multiply and grow in milk from the time it is collected until the time a person drinks it. If the milk is not pasteurized to kill germs, people who drink it can get sick.

Methods for collecting milk have improved over the years but cannot be relied on to be sure milk is safe to drink. Raw milk from “certified,” “organic,” or “local” dairies is not guaranteed to be safe. Pasteurization makes milk safe to drink. You can find pasteurized organic milk and products made from it at many locations.

Is it legal to buy or sell raw milk?

In some states it is legal to buy or sell raw milk. Because of the chance for serious illness, federal law prohibits dairies from distributing raw milk across state lines in final package form (packaged so that it can be consumed). This means that raw milk can be distributed across state lines only if it is going to undergo additional processing (e.g., pasteurization or used to make certain types of cheeses) before being sold to consumers. Each state makes its own laws about selling raw milk within the borders of the state. In fewer than half of states, selling raw milk directly to consumers is illegal. In the remaining 27 states, raw milk may be sold directly to consumers in some capacity.

How many outbreaks are related to raw milk?

From 2013 through 2018, 75 outbreaks reported to CDC were linked to raw milk. These outbreaks included 675 illnesses and 98 hospitalizations. Most of the outbreaks were caused by Campylobacter, Shiga toxin-producing E. coli, or Salmonella.

CDC collects data on foodborne disease outbreaks voluntarily reported by state, local, or territorial health departments.

Reported outbreaks represent the tip of the iceberg. Most illnesses are not part of a recognized outbreak, and for every outbreak and every illness reported, many others occur.

Many raw milk outbreaks involve people 19 years or younger. At least one person younger than 19 was involved in 48% of the raw milk outbreaks reported to CDC from 2013 through 2018. Of the 74 outbreaks that occurred in a single state, 58 (78%) were in states where the sale of unpasteurized milk was allowed.

Do more outbreaks related to raw milk occur in states where it is legal to sell?

Yes. States that allow the legal sale of raw milk for human consumption have more raw milk–related outbreaks than states that do not allow raw milk to be sold legally.

1. Is it safe to consume raw milk?

No. FDA and other health agencies such as the Centers for Disease Control and organizations such as the American Academy of Pediatrics agree that raw milk is unsafe because it can contain disease-causing pathogens, including:

• Enterotoxigenic Staphylococcus aureus
• Campylobacter jejuni
• Salmonella species
• E. coli
• Listeria monocytogenes
• Mycobacterium tuberculosis
• Mycobacterium bovis
• Brucella species
• Coxiella Burnetii
• Yersinia enterocolitica

Illnesses caused by these bacteria can be especially problematic for infants, young children, the elderly, and the immunocompromised. One complication that can arise as a result of infection with E. coli O157:H7 is hemolytic uremic syndrome (HUS), which can cause acute renal failure, especially in the very young or the elderly.

2. Have any illnesses or deaths been caused by consuming raw milk products?

Based on CDC data, literature, and state and local reports, FDA compiled a list of outbreaks that occurred in the U.S. from 1987 to September 2010. During this period, there were at least 133 outbreaks due to the consumption of raw milk and raw milk products. These outbreaks caused 2,659 cases of illnesses, 269 hospitalizations, 3 deaths, 6 stillbirths and 2 miscarriages. Because not all cases of foodborne illness are recognized and reported, the actual number of illnesses associated with raw milk likely is greater.

3. What are some of the symptoms of illnesses that can be caused by consuming raw milk?

Symptoms of illness caused by consuming raw milk include: vomiting, diarrhea, abdominal pain, fever, headache, and body ache. Most healthy people will recover from illness caused by harmful bacteria in raw milk - or in foods made with raw milk - within a short period of time, however, some individuals can develop symptoms that are chronic, severe, or even life threatening.

If you or someone you know becomes ill after consuming raw milk - or, if you are pregnant and think you could have consumed contaminated raw milk or cheese made from raw milk - see a doctor or healthcare provider immediately.

4. Are there any benefits to drinking raw milk?

No. As a science-based regulatory agency, the FDA looks to the scientific literature for information on benefits and risks associated with raw milk. While the perceived nutritional and health benefits of raw milk consumption have not been scientifically substantiated, the health risks are clear. 

5. Is it legal to sell raw milk for human consumption?

Not in interstate commerce. Pasteurization of milk was adopted decades ago as a basic public health measure to kill dangerous bacteria and largely eliminate the risk of getting sick from one of the most important staples of the American diet. In 1987, the FDA issued a regulation prohibiting the interstate sale of raw milk. However, some states do permit the intrastate (within the borders) sale of raw milk intended for human consumption.

6. How does the pasteurization of raw milk protect consumers?

Pasteurization is a process that kills harmful bacteria by heating milk to a specific temperature for a set period of time. Pasteurization kills the bacteria responsible for diseases such as listeriosis, salmonellosis, campylobacteriosis, typhoid fever, tuberculosis, diphtheria, and brucellosis, as well as other bacteria. However, pasteurized milk still contains low levels of the type of nonpathogenic bacteria that can cause food to spoil, so it is important to keep pasteurized milk refrigerated.

7. Does pasteurization affect the nutrient content of milk?

Research shows no meaningful difference between the nutrient content of pasteurized and unpasteurized milk.

8. Does pasteurizing milk alter it in a fashion that can cause allergic reactions?

No. The milk proteins which cause allergic reactions in dairy-sensitive people are present in both raw milk and pasteurized milk.

9. Can drinking pasteurized milk cause lactose intolerance?

No. Lactose intolerance is due to an insufficient production in the body of the enzyme needed to break down lactose, beta-galactosidase. Lactose is present in both raw milk and pasteurized milk at the same concentration. Pasteurization does not impact the concentration of lactose.

10. Does raw milk kill pathogens?

No, it does not. In fact, raw milk potentially harbors a wide range of dangerous pathogens that can cause illness.

11. Does consuming raw milk cure some illnesses and allergies?

There is no scientific evidence to demonstrate that raw milk has any effect on illness or allergies.

Milk and milk products provide a wealth of nutrition benefits. But raw milk, i.e., unpasteurized milk, can harbor dangerous microorganisms that can pose serious health risks to you and your family.

According to the Centers for Disease Control and Prevention (CDC), from 1993 through 2012, there were 127 outbreaks linked to raw milk or raw milk products like ice cream, soft cheese, or yogurt. They resulted in 1,909 illnesses and 144 hospitalizations. CDC points out that most foodborne illnesses are not a part of recognized outbreaks, and for every illness reported, many others occur.

Raw milk is milk from cows, sheep, and goats — or any other animal — that has not been pasteurized to kill harmful bacteria. Raw milk can carry dangerous bacteria such as Salmonella, E. coli, Listeria, Campylobacter, and others that cause foodborne illness, often called “food poisoning.”

These bacteria can seriously injure the health of anyone who drinks raw milk or eats products made from raw milk. However, the bacteria in raw milk can be especially dangerous to people with weakened immune systems (such as transplant patients and individuals with HIV/AIDS, cancer, and diabetes), children, older adults, and pregnant women. In fact, CDC finds that foodborne illness from raw milk especially affects children and teenagers.

"Pasteurized Milk" Explained

Pasteurization is a widely used process that kills harmful bacteria by heating milk to a specific temperature
for a set period of time. First developed by Louis Pasteur in 1864, pasteurization kills harmful organisms responsible for such diseases as listeriosis, typhoid fever, tuberculosis, diphtheria, Q fever, and brucellosis.

The Dangers of Listeria and Pregnancy

Pregnant women run a serious risk of becoming ill from the bacteria Listeria, which is often found in raw milk and can cause miscarriage, or illness, or death of the newborn baby. If you are pregnant, drinking raw milk — or eating foods made from raw milk, such as Mexican-style cheese like Queso Blanco or Queso Fresco — can harm your baby even if you don’t feel sick.

Raw Milk and Serious Illness

Symptoms and Advice

Symptoms of foodborne illness usually include:

• Vomiting, diarrhea, and abdominal pain
• Flu-like symptoms such as fever, headache, and body ache

While most healthy people will recover from an illness caused by harmful bacteria in raw milk – or in foods made with raw milk – within a short time, some can develop symptoms that are chronic, severe, or even life-threatening. If you or someone you know becomes ill after consuming raw milk or products made from raw milk – or, if you are pregnant and think you may have consumed contaminated raw milk or cheese – see a healthcare professional immediately.

Raw Milk & Pasteurization: Debunking Milk Myths

While pasteurization has helped provide safe, nutrient-rich milk and cheese for over 120 years, some people continue to believe that pasteurization harms milk and that raw milk is a safe, healthier alternative.

Here are some common myths and proven facts about milk and pasteurization:

• Pasteurizing milk DOES NOT cause lactose intolerance and allergic reactions. Both raw milk and pasteurized milk can cause allergic reactions in people sensitive to milk proteins.
• Raw milk DOES NOT kill dangerous pathogens by itself.
• Pasteurization DOES NOT reduce milk's nutritional value.
• Pasteurization DOES NOT mean that it is safe to leave milk out of the refrigerator for extended time, particularly after it has been opened.
• Pasteurization DOES kill harmful bacteria.
• Pasteurization DOES save lives.

When in Doubt — Ask!

• Read the label. Safe milk will have the word “pasteurized” on the label. If the word “pasteurized” does not appear on a product’s label, it may contain raw milk.
• Don’t hesitate to ask your grocer or health food store clerk whether milk or cream has been pasteurized, especially milk or milk products sold in refrigerated cases.
• Don’t buy milk or milk products at farmers’ markets or roadside stands unless you can confirm that they have been pasteurized.

Is Your Homemade Ice Cream Safe?

Each year, homemade ice cream causes serious outbreaks of infection from Salmonella. The ingredient responsible is raw or undercooked eggs. If you choose to make ice cream at home, use a pasteurized egg product, egg substitute, or pasteurized shell eggs in place of the raw eggs in your favorite recipe. There are also many egg-free ice cream recipes available.

Protect Your Family with Wise Food Choices

Most milk and milk products sold commercially in the United States contain pasteurized milk or cream, or the products have been produced in a manner that kills any dangerous bacteria that may be present. But, unpasteurized milk and products made from unpasteurized milk are sold and may be harmful to your health. To avoid getting sick from the dangerous bacteria found in raw milk, you should choose your milk and milk products carefully. Follow these guidelines:

Low Risk Choices

• Pasteurized milk or cream
• Hard cheeses such as cheddar, and extra hard grating cheeses such as Parmesan
• Soft cheeses, such as Brie, Camembert, blue-veined cheeses, and Mexican-style soft cheeses such as Queso Fresco, Panela, Asadero, and Queso Blanco made from pasteurized milk
• Processed cheeses
• Cream, cottage, and Ricotta cheese made from pasteurized milk
• Yogurt made from pasteurized milk
• Pudding made from pasteurized milk
• Ice cream or frozen yogurt made from pasteurized milk

High Risk Choices

• Unpasteurized milk or cream
• Soft cheeses, such as Brie and Camembert, and Mexican-style soft cheeses such as Queso Fresco, Panela, Asadero, and Queso Blanco made from unpasteurized milk
• Yogurt made from unpasteurized milk
• Pudding made from unpasteurized milk
• Ice cream or frozen yogurt made from unpasteurized milk

Safe Food Handling: Four Simple Steps

CLEAN

Wash hands and surfaces often

• Wash your hands with warm water and soap for at least 20 seconds before and after handling food and after using the bathroom, changing diapers, and handling pets.
• Wash your cutting boards, dishes, utensils, and counter tops with hot soapy water after preparing each food item.
• Consider using paper towels to clean up kitchen surfaces. If you use cloth towels, launder them often in the hot cycle.
• Rinse fresh fruits and vegetables under running tap water, including those with skins and rinds that are not eaten. Scrub firm produce with a clean produce brush.
• With canned goods, remember to clean lids before opening.

SEPARATE

Separate raw meats from other foods

• Separate raw meat, poultry, seafood, and eggs from other foods in your grocery shopping cart, grocery bags, and refrigerator.
• Use one cutting board for fresh produce and a separate one for raw meat, poultry, and seafood.
• Never place cooked food on a plate that previously held raw meat, poultry, seafood, or eggs unless the plate has been washed in hot, soapy water.
• Don’t reuse marinades used on raw foods unless you bring them to a boil first.

COOK

Cook to the right temperature

• Color and texture are unreliable indicators of safety. Using a food thermometer is the only way to ensure the safety of meat, poultry, seafood, and egg products for all cooking methods. These foods must be cooked to a safe minimum internal temperature to destroy any harmful bacteria.
• Cook eggs until the yolk and white are firm. Only use recipes in which eggs are cooked or heated thoroughly.
• When cooking in a microwave oven, cover food, stir, and rotate for even cooking. If there is no turntable, rotate the dish by hand once or twice during cooking. Always allow standing time, which completes the cooking, before checking the internal temperature with a food thermometer.
• Bring sauces, soups and gravy to a boil when reheating.

CHILL

Refrigerate foods promptly

• Use an appliance thermometer to be sure the temperature is consistently 40° F or below and the freezer temperature is 0° F or below.
• Refrigerate or freeze meat, poultry, eggs, seafood, and other perishables within 2 hours of cooking or purchasing. Refrigerate within 1 hour if the temperature outside is above 90° F.
• Never thaw food at room temperature, such as on the counter top. There are three safe ways to defrost food: in the refrigerator, in cold water, and in the microwave. Food thawed in cold water or in the microwave should be cooked immediately.
• Always marinate food in the refrigerator.
• Divide large amounts of leftovers into shallow containers for quicker cooling in the refrigerator.