Raw Milk Possibly Tied to Intestinal Infections

Raw milk tied to Campylobacter and Salmonella infections in Minnesota study

/ Author:  / Reviewed by: Joseph V. Madia, MD Beth Bolt, RPh

(RxWiki News) In certain circles, the word "raw" has become synonymous with the word "healthy." But the researchers behind a recent study warned that this is not always the case — especially when it comes to milk.

These researchers examined cases of intestinal infections in Minnesota that weren't tied to outbreaks.

Their study found that some of these patients consumed raw milk, and some had severe medical results from their infections.

"If you are unsure whether a product has been pasteurized, ask a sales clerk."

This study was led by Trisha J. Robinson, epidemiologist with the Minnesota Department of Health.

According to Robinson and colleagues, farm families have traditionally been the main consumers of raw (or unpasteurized) milk that has not undergone a process to kill bacteria — but these groups might be growing.

"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," these researchers explained. "Some raw milk advocates fail to acknowledge the elevated health risk associated with raw milk consumption and minimize the significance of reported outbreaks."

According to the authors of this study, raw milk has often been indicated as a source in foodborne illnesses, and it has been estimated that raw dairy carries a 150 times greater risk for foodborne illness than pasteurized dairy, but the specific numbers are not known. This is partially due to the fact that many raw milk-related illnesses might be "sporadic" — or an isolated event that is not related to a wider outbreak.

To further investigate these sporadic cases, Robinson and team looked at data on enteric, or intestinal, infections reported in the state of Minnesota — a state that allows some sales of raw milk, often at farms — during the years 2001 to 2010.

A total of 14,339 cases were analyzed. These cases included infections with the bacteria Campylobacter, Escherichia coli (E. coli) and Salmonella, and the protozoan parasite Cryptosporidium.

Of these patients with sporadic enteric infections, 3.7 percent (530 patients) reported consuming raw milk during their "exposure period" — the time in which they were likely to have been exposed to the pathogen that made them ill.

The researchers excluded 273 additional cases because the type of infection seen was not historically associated with raw milk. Only 0.7 percent (2 patients) of this group reported raw milk consumption.

Some severe illness was seen. Of the patients who reported consuming raw milk, 13 percent (70 patients) required hospitalization for an average of three days, with stays ranging from two to 27 days.

A condition called hemolytic uremic syndrome, in which an infection causes damage to the kidney, was seen in 21 percent of the patients with E. coli infections (19 patients) who consumed raw milk. One of these patients, a child under the age of 1, died.

Further research that explores the connection between raw milk and enteric infections is needed.

However, the authors of this study noted that their findings hint that sporadic raw milk infections likely greatly exceed the number seen in larger outbreaks, as they found 530 possible sporadic cases and excluded only 21 infections tied to known raw milk related-outbreaks during the same time period.

"Raw milk consumers, potential consumers, and policy makers who might consider relaxing regulations regarding raw milk sales should be educated regarding illnesses associated with raw milk consumption," Robinson and colleagues wrote.

It is important to note the US Food and Drug Administration (FDA) does not recommend consuming unpasteurized dairy products.

This article will be published in the January issue of CDC's journal, Emerging Infectious Diseases. No conflicts of interest were reported.

Review Date: 
December 10, 2013
Last Updated:
December 11, 2013