The Perils of Raw Milk Linda K. Gaul, PhD, MPHEpidemiologist, Infectious Disease Control Unit

History of Raw Milk Consumption, Illnesses, and Regulation

History of Pasteurization and Milk-Associated IllnessesPasteur worked on process to prevent wine spoilagePasteurization is the heat treatment of food to kill bacteriaEarly 1900s, pasteurization used for milkFewer milkborne infections were notedIn the 1930s, milk pasteurization was mandated in many large citiesIn 1938, milkborne outbreaks made up ~25% of outbreaks due to contaminated food and water

Hall, C.W and Trout, GM. Milk Pasteurization; AVI Publishing Company; 1968.LeJeune, J.T. and Rajala-Schultz, P.J. CID. 2009;48:93-100.

Pathogens Historically Associated With Raw MilkCampylobacter sp.Shiga-toxin producing Escherichia coli (STEC)Including E. coli O157:H7Salmonella sp.Listeria monocytogenesStaphylococcus aureusYersinia enterocoliticaMycobacterium bovis - Bovine tuberculosisBrucella melitensis

Dairy animals are reservoirs for these organismsToday, M. bovis and B. melitensis are controlled by nationwide eradication programs for cattle herds. Occasionally, infected cattle are still found.

History of Pasteurization and Milk-Associated Illnesses, continuedBy 1950, pasteurization was standard for commercial US milk supplyNearly all pasteurized milk today is heated to 161oF for 15 secondsIn 2000, milkborne outbreaks made up

Achievements in Public Health, 1900-1990Safer and Healthier FoodsMorbidity and Mortality Week ReportOctober 15, 1999

Once the sources and characteristics of foodborne diseases were identified--long before vaccines or antibiotics--they could be controlled by handwashing, sanitation, refrigeration, pasteurization, and pesticide application.

Regulation of Raw Milk SalesIn 1987, FDA prohibited interstate sales of unpasteurized milkThe FDA does not regulate intrastate salesEach state regulates intrastate unpasteurized milk salesStates vary in the type of raw milk sales that are allowed, if anyThe sale of raw milk is illegal in 20 states30 states allow the sale of raw milk in certain settings13 allow retail store sales14 allow on-farm sales only (including Texas)2 states allow sales by prescription only1 state allows sales through purchase of cow sharesLicensing and requirements for raw milk sales vary by state, where allowed

Status of Raw Milk Sales, 2008Centers for Disease Control and Prevention (CDC), October 2009

Milk Consumption Preferences 2002-2003 FoodNet SurveyConsumer 23 times more likely to drink pasteurized milk U.S. Census Bureau, http://www.census.gov/popest/estimates.html*Estimated US population 288 million in 2002-03Milk consumption during the past 7 days:

Survey pop.Estimated US Milk typedrinkingpop. drinking (#) Any kind81.6%248,000,000Unpasteurized3.5%8,680,000

Epidemiology of Illnesses Associated with Raw Milk Consumption

How Illnesses are Associated with Specific FoodsSporadic cases are only rarely linked to a specific food vehicleOutbreak data provide the best evidence for links to food vehiclesMilkborne outbreaks have been associated with:Unpasteurized milk and milk productsInadequately pasteurized or post-pasteurization contaminated milk and milk products

*Milk-Associated Outbreaks,Scotland, 1980-2004

Sharp. J Med Micro. 1989. 29:239-242.; Food Standards Agency, 5/11/2009.

Chart3

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18

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2

1983 Legislation Prohibits Sale of Raw Milk

1986 Legislation Prohibits payment to farm workers in raw milk

1424Cases

126Cases

45Cases

Outbreaks from 1986-2004 limited to farm families

# of Outbreaks

Sheet1

YearsOutbreaksCases

1980-1982271424

1983-198518126

1986-1988945

1989-2004210

Sheet1

1983 Legislation Prohibits Sale of Raw Milk

1986 Legislation Prohibits payment to farm workers in raw milk

1424Cases

126Cases

45Cases

Outbreaks from 1986-2004 limited to farm families

# of Outbreaks

Sheet2

Sheet3

Raw Milk Associated Outbreaks, US, 1973-199246 outbreaks reported from 21 states1733 cases40 (86%) occurred in states where raw milk sale was legal at time of outbreak6 (14%) occurred in states where raw milk sale was not legal at time of outbreak

6 times as many outbreaks in states where raw milk sales were legal

Headrick, et al. 1998 AJPH.88:1219-1221

Raw Milk Associated Outbreaks, US, 1998-2007Center for Disease Control and Prevention (CDC): October 2009 41 (80%) occurred in states where raw milk sale was legal at time of outbreak 10 (20%) occurred in states where raw milk sale was not legal at time of outbreak4 times as many outbreaks in states where raw milk sales were legal

Sheet1

RawPasteurized**

MilkMilk

Number of Outbreaks5112

Number of Cases10542213

Number of Hospitalizations5725

**The pasteurized milk outbreaks were traced back to attempted pasteurization that failed or contamination after pasteurization

RawPasteurized**

MilkMilk

Number of Outbreaks5112

Outbreak Pathogens

Campylobacter Spp423

Escherichia coli O157:H770

Listeria monocytogenes01

Salmonella Spp23

Unknown agent05

**The pasteurized milk outbreaks were traced back to attempted pasteurization that failed or contamination after pasteurization

Reported Outbreaks Associated with Raw Milk 1998-2007National Association of State Departments of Agriculture Raw Milk Survey April 2008; CDC, October 2009

Pathogens in Raw Milk Associated Outbreaks, US, 1998-2007Center for Disease Control and Prevention (CDC): October 2009

Sheet1

RawPasteurized**

MilkMilk

Number of Outbreaks5112

Number of Cases10542213

Number of Hospitalizations5725

**The pasteurized milk outbreaks were traced back to attempted pasteurization that failed or contamination after pasteurization

RawPasteurized**

MilkMilk

Number of Outbreaks5112

Outbreak Pathogens

Campylobacter Spp423

Escherichia coli O157:H770

Listeria monocytogenes01

Salmonella Spp23

Unknown agent05

**The pasteurized milk outbreaks were traced back to attempted pasteurization that failed or contamination after pasteurization

Texas Outbreaks Associated with Raw Milk

Texas Outbreaks Associated with Raw Milk or Raw Milk Cheese*2000 Campylobacteriosis outbreak2 casesSampled raw goat milk at a conferenceIncluded in 1998-2007 outbreak summary slide2003-2009 Listeriosis outbreak46 cases, 9 deaths29 mother-baby sets (5 miscarriages, stillbirths, infant deaths)17 immonocompromised persons (4 deaths)Case-patients consumed unpasteurized queso fresco (cow milk)Cheese produced in MexicoCheese carried legally into USCheese sold illegally in USNOT included in 1998-2007 summary slide

*Cheeses not included in other outbreak information

Campylobacteriosis Outbreaks Associated with Raw Milk, Youth Activities, US, 1981-1990CDC survey of 50 states, Puerto RicoYouth activities: School field trips to dairy farms, other20 outbreaks, 11 states1013 youths, adults drank raw milk, 458 illAttack rate 45%12 known hospitalizations, no deaths70% of outbreaks with children K-3rd gradeOnly 60% of outbreaks reported to CDCWood, et al. 1992. JAMA. 268:3228-3230.

Nutritional and Other Health Considerations, Raw vs. Pasteurized Milk

Claimed Advantages of Unpasteurized Milk over Pasteurized Milk: Are These Real?There are no scientific studies reported in peer-reviewed literature that show any advantage of unpasteurized milk over pasteurizedSome raw milk advocates claim that certain beneficial proteins and other chemicals are degraded substantially during pasteurizationMilk is not a significant source for some of these chemicals, such as vitamin COnly ultra-high temperature pasteurization destroys many other chemicalsUnpasteurized milk always carries with it the risk of illness caused by pathogensThe nutrients for which milk is an important source are not destroyed or altered by pasteurizationCalcium, protein

Characteristics of Human Breast Milk and Animal MilkHuman breast milkMother produces antibodies, other protective substances against pathogens in her environmentMilk is sterileUnless mother has an infectionUnpasteurized animal milkAnimals produce antibodies, other protective substances against pathogens in their environmentMilk is not sterile, Even if animals are healthy

Newman. 1995. SA:273:76-79; Potter, 1984. JAMA:252, 2048-2052

Characteristics of Human Breast Milk and Animal MilkHuman breast milkSubstances suppress harmful bacteria and block their absorption, promote beneficial bacteriaBenefits last only ~3 months, when babys immune system becomes more matureUnpasteurized animal milkSubstances may suppress harmful bacteria and block their absorption, promote beneficial bacteriaAny benefits would last only ~3 months, when babys immune system becomes more matureNewman. 1995. SA:273:76-79; Potter, 1984. JAMA:252, 2048-2052

American Academy Of PediatricsPosition Statement

Prevention of disease in children is one of the Academys highest priorities. Raw milk is known to transmit infectious diseases, and pasteurization is known to minimize risk. Raw milk has no benefits that would justify any increase in risk to children. The Academy supports legislation efforts at both the state and national levels that mandate pasteurization of all dairy products.

Bradley et. al. December 2008. AAP News. Volume 29

Regulation of Raw Milk in Texas

Current Raw Milk Regulations In Texas