Raw Milk Consumption among Patients with Non–Outbreak-related Enteric Infections, Minnesota, USA, 2001–2010 - Volume 20, Number 1—January 2014 - Emerging Infectious Disease journal - CDC
Volume 20, Number 1—January 2014
Raw Milk Consumption among Patients with Non–Outbreak-related Enteric Infections, Minnesota, USA, 2001–2010
Author affiliations: Minnesota Department of Health, St. Paul, Minnesota, USA
Raw milk is well-established as a vehicle for numerous infectious diseases (1–8) and has frequently been identified as the source of outbreaks of foodborne illness (9,10). From 1998 through 2011, a total of 148 outbreaks were documented in the United States associated with the consumption of raw milk products, resulting in 2,384 illnesses, 284 hospitalizations, and 2 deaths (11). A recent report concluded that the incidence of reported outbreaks associated with raw dairy products was ≈150 times greater, per unit of product consumed, than the incidence involving pasteurized dairy products (12).
Although pasteurization has been available for use in the United States for over a century, a small proportion of the population continues to consume raw milk. In a 2006–2007 population survey comprising 10 states in the Foodborne Diseases Active Surveillance Network, 3.0% of respondents reported consuming raw milk during the previous 7 days (13). Farm families have traditionally been the primary consumers of raw milk, but evidence in recent years suggests that the population of raw milk consumers may be changing (14). Raw milk advocates tout raw milk for its purported health benefits and better taste, and many persons view raw milk consumption as an opportunity to support local dairies (15,16). Some raw milk advocates fail to acknowledge the elevated health risk associated with raw milk consumption and minimize the significance of reported outbreaks. In doing so, these advocates convey a false sense of the safety of raw milk to those who are considering consuming this product, and this sense of safety discourages a balanced assessment of the potential risks and benefits involved.
Although outbreaks associated with raw milk occur frequently and receive much media attention, the number of reported cases determined to be outbreak-related likely represents a small proportion of the actual number of illnesses associated with this product. Two lines of evidence support this assumption. First, among reported illnesses caused by enteric pathogens that are laboratory-confirmed, non–outbreak-related (i.e., sporadic) cases far outnumber those associated with recognized outbreaks (17). Second, for each reported laboratory-confirmed illness caused by a bacterial or protozoal enteric pathogen, an estimated 26–100 additional illnesses likely occur, depending on the pathogen (18). Therefore, any estimates of the number of illnesses associated with raw milk consumption should include an evaluation of sporadic cases, including multipliers to account for underdiagnosis and underreporting. However, little information is available on the number of sporadic cases of illness associated with raw milk consumption.
Minnesota is among the 30 US states that permit raw milk to be sold in some capacity (19), allowing for raw milk to be occasionally secured or purchased for personal use at the farm or place where the milk is produced (20). To better estimate the true number of human enteric pathogen infections associated with consumption of raw milk, we characterized sporadic enteric illnesses that occurred among patients in Minnesota who reported raw milk consumption during 2001–2010. Our primary objective was to provide better data on the true number of sporadically occurring disease cases associated with raw milk consumption.
We thank the many staff members of the Foodborne, Vectorborne, and Zoonotic Diseases Unit at the Minnesota Department of Health who helped collect data used in this report.
This work was supported in part through cooperative agreements (5 U01 EH000698-03 and U50/CCU511190) with the Centers for Disease Control and Prevention as part of the Environmental Health Specialist’s Network and the Emerging Infections Program, Foodborne Diseases Active Surveillance Network.
- Table 1. Demographic characteristics of patients with domestically acquired, sporadic enteric infections, Minnesota, 2001–2010
- Table 2. Number of sporadic illnesses resulting from raw milk consumption, as estimated by using underdiagnosis multipliers, Minnesota, 2001–2010
Suggested citation for this article: Robinson TJ, Scheftel JM, Smith KE. Raw milk consumption among patients with non–outbreak-related enteric infections, Minnesota, USA, 2001–2010. Emerg Infect Dis [Internet]. 2014 Jan [date cited]. http://dx.doi.org/10.3201/eid2001.120920