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The Perils of Raw Milk

The Perils of Raw Milk. Linda K. Gaul, PhD, MPH Epidemiologist, Infectious Disease Control Unit. History of Raw Milk Consumption, Illnesses, and Regulation. History of Pasteurization and Milk-Associated Illnesses. Pasteur worked on process to prevent wine spoilage

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The Perils of Raw Milk

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  1. The Perils of Raw Milk Linda K. Gaul, PhD, MPH Epidemiologist, Infectious Disease Control Unit

  2. History of Raw Milk Consumption, Illnesses, and Regulation

  3. History of Pasteurization and Milk-Associated Illnesses Pasteur worked on process to prevent wine spoilage Pasteurization is the heat treatment of food to kill bacteria Early 1900s, pasteurization used for milk Fewer milkborne infections were noted In the 1930s, milk pasteurization was mandated in many large cities In 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.

  4. Pathogens Historically Associated With Raw Milk Campylobacter sp. Shiga-toxin producing Escherichia coli (STEC) Including E. coli O157:H7 Salmonella sp. Listeria monocytogenes Staphylococcus aureus Yersinia enterocolitica Mycobacterium bovis - Bovine tuberculosis Brucella melitensis Dairy animals are reservoirs for these organisms Today, M. bovis and B. melitensis are controlled by nationwide eradication programs for cattle herds. Occasionally, infected cattle are still found.

  5. History of Pasteurization and Milk-Associated Illnesses, continued By 1950, pasteurization was standard for commercial US milk supply Nearly all pasteurized milk today is heated to 161oF for 15 seconds In 2000, milkborne outbreaks made up <1% of outbreaks due to contaminated food and water

  6. Achievements in Public Health, 1900-1990Safer and Healthier Foods Morbidity and Mortality Week Report October 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.”

  7. Regulation of Raw Milk Sales In 1987, FDA prohibited interstate sales of unpasteurized milk The FDA does not regulate intrastate sales Each state regulates intrastate unpasteurized milk sales States vary in the type of raw milk sales that are allowed, if any The sale of raw milk is illegal in 20 states 30 states allow the sale of raw milk in certain settings 13 allow retail store sales 14 allow on-farm sales only (including Texas) 2 states allow sales by prescription only 1 state allows sales through purchase of “cow shares” Licensing and requirements for raw milk sales vary by state, where allowed

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

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

  10. Epidemiology of Illnesses Associated with Raw Milk Consumption

  11. How Illnesses are Associated with Specific Foods Sporadic cases are only rarely linked to a specific food vehicle Outbreak data provide the best evidence for links to food vehicles Milkborne outbreaks have been associated with: Unpasteurized milk and milk products Inadequately pasteurized or post-pasteurization contaminated milk and milk products

  12. Milk-Associated Outbreaks,Scotland, 1980-2004 Sharp. J Med Micro. 1989. 29:239-242.; Food Standards Agency, 5/11/2009.

  13. Raw Milk Associated Outbreaks, US, 1973-1992 • 46 outbreaks reported from 21 states • 1733 cases • 40 (86%) occurred in states where raw milk sale was legal at time of outbreak • 6 (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

  14. Raw Milk Associated Outbreaks, US, 1998-2007 • 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 outbreak • 4 times as many outbreaks in states where raw milk sales were legal Center for Disease Control and Prevention (CDC): October 2009

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

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

  17. Texas Outbreaks Associated with Raw Milk

  18. Texas Outbreaks Associated with Raw Milk or Raw Milk Cheese* 2000 Campylobacteriosis outbreak 2 cases Sampled raw goat milk at a conference Included in 1998-2007 outbreak summary slide 2003-2009 Listeriosis outbreak 46 cases, 9 deaths 29 mother-baby sets (5 miscarriages, stillbirths, infant deaths) 17 immonocompromised persons (4 deaths) Case-patients consumed unpasteurized queso fresco (cow milk) Cheese produced in Mexico Cheese carried legally into US Cheese sold illegally in US NOT included in 1998-2007 summary slide *Cheeses not included in other outbreak information

  19. Campylobacteriosis Outbreaks Associated with Raw Milk, Youth Activities, US, 1981-1990 CDC survey of 50 states, Puerto Rico Youth activities: School field trips to dairy farms, other 20 outbreaks, 11 states 1013 youths, adults drank raw milk, 458 ill Attack rate 45% 12 known hospitalizations, no deaths 70% of outbreaks with children K-3rd grade Only 60% of outbreaks reported to CDC Wood, et al. 1992. JAMA. 268:3228-3230.

  20. Nutritional and Other Health Considerations, Raw vs. Pasteurized Milk

  21. 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 pasteurized Some raw milk advocates claim that certain beneficial proteins and other chemicals are degraded substantially during pasteurization Milk is not a significant source for some of these chemicals, such as vitamin C Only ultra-high temperature pasteurization destroys many other chemicals Unpasteurized milk always carries with it the risk of illness caused by pathogens The nutrients for which milk is an important source are not destroyed or altered by pasteurization Calcium, protein

  22. Characteristics of Human Breast Milk and Animal Milk Human breast milk Mother produces antibodies, other protective substances against pathogens in her environment Milk is sterile Unless mother has an infection Unpasteurized animal milk Animals produce antibodies, other protective substances against pathogens in their environment Milk is not sterile, Even if animals are healthy Newman. 1995. SA:273:76-79; Potter, 1984. JAMA:252, 2048-2052

  23. Characteristics of Human Breast Milk and Animal Milk Human breast milk Substances suppress harmful bacteria and block their absorption, promote beneficial bacteria Benefits last only ~3 months, when baby’s immune system becomes more mature Unpasteurized animal milk Substances may suppress harmful bacteria and block their absorption, promote beneficial bacteria Any benefits would last only ~3 months, when baby’s immune system becomes more mature Newman. 1995. SA:273:76-79; Potter, 1984. JAMA:252, 2048-2052

  24. American Academy Of PediatricsPosition Statement “Prevention of disease in children is one of the Academy’s 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

  25. Regulation of Raw Milk in Texas

  26. Current Raw Milk Regulations In Texas Farms selling Grade “A” Raw for Retail Milk must be licensed with DSHS However, DSHS is aware of some unlicensed farms The consumer can purchase raw milk from a farm that has a Grade “A” Raw for Retail permit Grade “A” Raw for Retail dairies have same requirements as the dairies that sell milk to be pasteurized, except Additional requirements for coliform and pathogen testing Milk must be stored at or below 45 ºF until sold

  27. Licensed Retail Raw Milk Farms 35 Licensed Grade “A” Raw for Retail Dairies

  28. “Consumption of raw milk remains a preventable cause of foodborne disease outbreaks.” Headrick, et al. 1998 AJPH.88:1219-1221

  29. Acknowledgements Julie Loera, Division of Regulatory Affairs, DSHS Frank Borden, Division of Regulatory Affairs, DSHS Gene Wright, Division of Regulatory Affairs, DSHS Maricela Montoya, WIC Clinical Services, DSHS Tracy Hayward, Division of Prevention and Preparedness, DSHS

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