Live Bird Markets Might Pose Extra Salmonella Risk

Salmonella infections tied to live bird markets in US study by CDC researchers

(RxWiki News) For some, getting poultry from a live market is a way of life and a tradition. But is it safe? New research warns that there might be a connection between these markets and Salmonella.

This study looked at recent outbreaks of Salmonella infections that were tied to live-bird or live-animal markets in the US.

The researchers found that these outbreaks often involved certain ethnic groups and young children, perhaps suggesting a needed change in food safety education.

"Be sure to cook meat and poultry completely before eating."

Infection with the bacteria Salmonella, or salmonellosis, can cause fever, diarrhea, cramps and sometimes hospitalization. According to the Centers for Disease Control and Prevention (CDC), around 42,000 cases of salmonellosis are reported each year in the US, and people can become ill after eating contaminated food or contact with contaminated animals.

"Since 2007, state and local health departments and the Centers for Disease Control and Prevention have investigated multiple salmonellosis outbreaks linked to meat purchased at live-bird markets (LBMs) and live-animal markets (LAMs), where poultry and livestock are sold for onsite slaughter," explained the authors of this study, who were led by Maho Imanishi, epidemiologist with CDC in Atlanta, Georgia.

"These markets typically operate in large cities and serve populations of diverse ethnic backgrounds," they wrote.

Imanishi and colleagues wanted to explore these outbreaks in-depth and understand more about the connection between Salmonella and live-bird markets. They examined recent Salmonella outbreaks reported to CDC with live-bird or live-animal market ties.

One 2007 outbreak in Massachusetts involved 62 patients who were infected with Salmonella. Most of the patients (96 percent) were Asian and a majority (61 percent) were under the age of 5. Fourteen (23 percent) were under 1 year old.

Exposure to poultry that was purchased at live-bird markets was reported by some of the patients. Sampling at one live-bird market involved in the outbreak identified six different types of Salmonella.

An additional three investigations of Salmonella tied to live-bird markets developed after the 2007 outbreak — a New York City outbreak in 2009 that involved 50 patients, a 2010-2011 multistate outbreak centered in New York, New Jersey and Massachusetts and a 2012 multistate outbreak centered in Illinois and Michigan.

Imanishi and colleagues reported that in these three outbreaks, the majority of patients were Asian or Hispanic, except for in Michigan where three out of five patients were Arab. The researchers also noted that over half of the patients were under 5 years old.

Exposure to poultry from live-bird markets seemed to be a common thread in these outbreaks. For patients with available information, 88 percent from the 2009 New York outbreak, 35 percent from the 2010-2011 multistate outbreak and 50 percent from the 2012 multistate outbreak reported exposure to this type of poultry.

According to Imanishi and colleagues, CDC saw a rise in Salmonella infections across the country during 2011 to 2012. No single reason for this increase was determined, but the researchers noted that several clusters of illnesses were linked to live-animal markets.

This included 14 illnesses in Minnesota linked to meat from three neighboring live-animal markets. Half of these patients were infants under the age of 1 and 10 were of Hmong ethnicity. Ten illnesses in California likely to be connected with pork, lamb and beef from three live-animal markets were identified among people with Hmong and Ethiopian ethnicity.

The authors of this study noted that these markets seem to be used by certain populations and ethnic groups, perhaps for cultural, culinary or religious reasons.

These authors offered a few reasons why there might be a connection between salmonellosis and live-bird or live-animal markets, including that though these markets must meet sanitation requirements, many are not subject to certain Food Safety and Inspection Service standards.

Additionally, "high-risk cultural preferences" were identified in the outbreaks, including practices like consuming raw or undercooked meat, and cooking parts of the animal (like feet or intestines) that are more likely to contain Salmonella.

"Further processing (e.g., de-feathering, butchering) conducted inside homes could lead to cross-contamination in the household environment," wrote Imanishi and colleagues. "Because of language and cultural barriers, existing food safety messages may not have been effective."

Further research is needed to confirm these findings. The study authors stressed that a more local, focused approach for food safety communications and education is needed to prevent illnesses in these environments.

The 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