Kathryn Falb (l), Sharon Greene

Kathryn Falb (l), Sharon Greene

HSPH student helps Mass. Department of Public Health analyze consequences of raw milk distribution

November 4, 2011

With the continuing trend toward ever-more “natural” diets, the raw milk debate has gathered steam, including here in Massachusetts where lawmakers have been considering legislation to loosen restrictions on selling raw milk for the nearly 30 dairy farms in the state.

The question at hand is whether these farms should be allowed to deliver raw milk—which is neither pasteurized nor homogenized—to customers. The pasteurization process heats milk to kill disease-causing microorganisms, and homogenization prevents a cream layer from separating out of the milk. Currently the farms can only sell raw milk directly to customers at the farm.

While the Massachusetts Department of Public Health (DPH), like other public health agencies and organizations, had concerns about health consequences associated with consumption of raw milk products, it was critical to look more broadly across the U.S. at the prevalence of food-borne illness and to better understand economic impacts associated with the distribution of raw milk.  Unfortunately, DPH didn’t have the resources to thoroughly explore these issues

State turns to HSPH for analysis

So DPH Commissioner John Auerbach turned for answers to the public health researcher expertise at Harvard Catalyst | The Harvard Clinical and Translational Science Center and their Community Health Innovation and Research Program (HC-CHIRP). The HC-CHIRP staff includes research faculty from Harvard’s School of Public Health (HSPH).

HC-CHIRP teams HSPH students up with scientists across Harvard University, its 11 schools, and 18 academic healthcare centers to conduct in-depth studies of public health issues that directly affect public policy. The students get a stipend, paid by Harvard Catalyst through their National Institutes of Health funding, and they conduct their project research while completing their regular coursework.

To fulfill their responsibility for safeguarding the health of the Commonwealth’s residents, DPH needed comprehensive information concerning the health consequences, costs, and arguments for and against increasing access to raw milk. DPH Commissioner John Auerbach was confident that HC-CHIRP would be able to provide timely, accurate, credible information.

This is the second time that DPH has turned to this program and HSPH students for help solving a public policy issue.  And given the positive results thus far, it appears that many more opportunities will arise in the months and years ahead.

Raw milk advocates claim that pasteurization destroys nutrients as well as enzymes important for calcium absorption. Opponents, among them scientists from the Food and Drug Administration and the Centers for Disease Control and Prevention (CDC) and other public health officials, warn of the danger of consuming the product. Raw milk, they say, may carry at least 11 disease-causing organisms that can lead to diarrhea, stomach cramps, vomiting, and, less commonly, kidney failure, paralysis, chronic disorders, and even death.

Kathryn Falb, a third-year doctoral student in HSPH’s Department of Society, Human Development, and Health, jumped at the chance to be paired with Sharon Greene, an epidemiologist in the Department of Population Medicine at Harvard Medical School and Harvard Pilgrim Health Care Institute, and an expert on food-borne illnesses. Greene was paired with Falb by Charles Deutsch, a senior research scientist at HSPH and head of the HC-CHIRP effort, who used the Harvard Catalyst Profiles to find the best faculty adviser for this project.

“A lot of our coursework centers on research methodology and study design and analysis,” said Falb. “This provided the opportunity to work with people making real, concrete policy at DPH, where you know your research will be implemented almost immediately and help people make informed decisions.”

Looking at state-by-state data

With Greene’s guidance, Falb scoured CDC databases on food-borne outbreaks around the country from 1998 through 2008 and the scientific literature on the epidemiology of raw milk disease outbreaks and current raw milk statutes. Her detailed 16-page report provides a state-by-state analysis of the legality of raw milk sales and cow-sharing programs (in which consumers pay a fee for the boarding and milking of a cow), as well as the restrictions in the 26 states where raw milk sales are legal. Those restrictions include where the raw milk can be sold (on the farm, in retail stores, by delivery) and rules regarding advertising, warning labels, permits, licenses, and bottling. The report also investigates the economic cost to dairies of loosening restrictions, given the increased monitoring such changes may require.

What rose to the surface in her analysis? From 2006 to 2008, the states with the most restrictions on the sale of raw milk had the lowest annual rate of illnesses from raw milk outbreaks—just 0.01 per 100,000 people. Moderately restrictive states came in a close second: 0.02-0.04 illnesses per 100,000 people.  The least restrictive states had the highest annual rate: 0.04-0.13 illnesses per 100,000 people. Over the 11-year span the report covered, a total of 1,204 illnesses were reported.

Further analysis reveals higher illness estimates

But Falb and Greene didn’t stop the analysis there. Because such illnesses are both underdiagnosed and underreported, the scientists adjusted their figures to estimate the true incidence of food-borne illnesses associated with raw milk. The difference is striking. “We estimate that approximately 35,000 illnesses may have occurred,” says Greene, referring to the 11-year time period. Most of those—some 23,000—were linked to the Campylobacter organism.

Still, from a policy perspective, the small difference in reported cases between the most restrictive and the moderately restrictive states provides food for thought. “Of course, even a small difference matters to the people who get sick,” says Falb. “But it will be up to the legislators to interpret how that difference will be meaningful regarding policy.”

The raw milk report will help Massachusetts legislators determine raw milk policy. DPH has shared the report with staff from other Massachusetts agencies, as well as with policy leaders in other states and at the CDC.

Students study “competitive” foods in schools

Falb and Greene’s raw milk project is HC-CHIRP’s second commission from the Massachusetts DPH, and several more are in the works. The first, which began in the fall of 2010, helped a Massachusetts nutritional-standards interagency workgroup develop guidelines for “competitive” foods in schools based on the latest science. “Competitive” foods are those that are not part of the school meal program, including offerings in vending machines, school stores, and fundraisers.

For that project, HSPH Department of Nutrition doctoral students Juliana Cohen and Jessica Garcia worked with their faculty adviser Eric Rimm, to ensure not only that the new standards would be realistic but also that schools would not lose money because of their implementation. Regarding the latter, for example, they found that in other states, when stricter standards were set, income stayed constant because students spent their money on school lunches if they didn’t like the healthier fare in the vending machines.

 “The project was a spectacular experience for both the students and myself,” said Rimm, associate professor in HSPH’s Departments of Epidemiology and Nutrition. “We got to see how research directly impacts policy and implementation in a setting of forward-thinking and extremely motivated government employees in the Massachusetts DPH.”

The food guidelines that the HSPH team helped DPH develop mirror the rigorous Institute of Medicine standards—and in some cases go even further. For example, whereas the IOM requires that all snack items be whole grain, the Massachusetts proposal requires that all grain-based foods—even pizza and hot dog buns—be whole grain. “These will be both the most progressive guidelines in the United States and also the most realistic,” says Cohen.

DPH Commissioner John Auerbach has praised HC-CHIRP in several public meetings. DPH is grateful for the continuing collaboration.  In order to develop evidence-based policy, DPH needs to locate and evaluate a great deal of research quickly and without additional cost outlay. In these severely constrained times, HC-CHIRP’s assistance is especially valuable to DPH.

–Thea Singer

photo: Aubrey LaMedica