Dr. Solenne Costard
EpiX Analytics
1643 Spruce Street
Boulder, CO 80302
scostard@epixanalytics.com

May 11, 2017

Dear Dr. Costard,

A recent study published in the June issue of Emerging Infectious Diseases, authored by you, Luis Espejo,
Huybert Groenendaal, and Francisco J. Zagmutt, and funded in part by a United States Department of
Agriculture Special Research Grant and the Pennsylvania Agricultural Experiment Station, draws
misleading conclusions by conflating outbreaks linked to fluid raw milk with outbreaks linked to cheese
produced from raw milk. The study, “Outbreak-Related Disease Burden Associated with Consumption of
Unpasteurized Cow’s Milk and Cheese, United States, 2009–2014,” also fails to distinguish between those
products produced legally and aged properly, and those produced at home and/or in unlicensed facilities.

The American Cheese Society (ACS) finds that this misrepresentation of data leads the authors of the
study to draw inaccurate conclusions about the safety of legally-produced and properly aged raw milk
cheeses. The authors of the study:

• inaccurately group data for fluid milk and cheese together, creating the false assumption that
  the risk is similarly associated with each of the grouped items
• lump together the few outbreaks linked to cheese with outbreaks linked to fluid milk, which
  make up the overwhelming majority of the outbreaks in the data set
•  use selection criteria for outbreaks that group together cheese and milk as ingredients and
  “cheese,” “milk,” and “dairy” as food vehicles
•  base conclusions on the grouped data, failing to consider that the components (fluid milk and
  cheese) are not equally represented
•  fail to distinguish between those products produced legally and aged properly, and those
  produced at home and/or in unlicensed facilities

It is important to note that the authors of other peer-reviewed studies, including Increased Outbreaks
Associated with Nonpasteurized Milk, United States, 2007-2012 (cited in S. Costard et al.) and Outbreaks
Attributed to Cheese: Differences Between Outbreaks Caused by Unpasteurized and Pasteurized Dairy
Products, United States, 1998-2011, analyzed much of the same data, yet clearly differentiated between
fluid milk and cheese. They also distinguished between those products produced legally and aged
properly, and those imported illegally, produced at home, and/or produced in unlicensed facilities. As a
result, they were able to come to more accurate conclusions.

ACS called attention to similarly misleading language conflating fluid raw milk and raw milk cheese in
2012, when ACS responded to a CDC Study on Nonpasteurized Dairy Products, Disease Outbreaks, and
State Laws. 

An article recently published in STAT, “Raw milk and cheese cause 840 times more illnesses than
pasteurized products,” furthers the misleading conclusions of your study. Its author, Helen Branswell,
begins by stating that “[u]npasteurized milk and cheeses made from it are responsible for nearly all
foodborne illnesses caused by contaminated dairy products.” She goes on to state that it “has been
thought that cheese made from raw milk was safe to eat if it is aged for 60 days; the aging is thought to kill
harmful bacteria. But the FDA is currently reviewing the scientific basis for that position.”

ACS has been in contact with FDA regarding this statement, and has been assured that there are currently
no pending changes to the 60 day aging rule. In fact, from 2014 to 2016, FDA conducted a very thorough
assignment testing legally produced and aged raw milk cheeses for the presence of the pathogens
Salmonella, Listeria monocytogenes, E. coli O157:H7, and Shiga toxin-producing E. coli. The overall
contamination rate for each of the pathogens was found to be less than one percent.

ACS has issued a Statement on the Safety of Raw Milk Cheese and endorses current FDA raw milk
cheese guidelines for manufacturers, including:
• producing cheese in licensed facilities that are routinely inspected on the local, regional, and
federal level
• producing cheese under the oversight of licensed dairy handlers
• aging cheese for a minimum of 60 days before it is sold

In addition, FDA has reviewed ACS’s Best Practices Guide for Cheesemakers which further advocates
producers:
• take part in ongoing food safety education
• regularly conduct product and environmental testing
• maintain accurate and up-to-date records
• seek third party certification
• build relationships with local, regional, and federal inspectors
• adhere to all state and federal regulations and industry standards

Please see our websites www.cheesesociety.org and www.safecheesemaking.org for complete, thorough,
and up-to-date information on safe cheesemaking, and accurate facts about the industry.

Nora Weiser
Executive Director
Cc: Editors, Emerging Infectious Diseases
Helen Branswell, Infectious Diseases and Public Health reporter, STAT
Editors, STAT