A newly published study of outbreaks linked to organic food concludes that while more data are needed to assess whether the risk is greater than for conventionally grown food, consumers should practice safe food handling in any case to avoid being sickened.

The study, from researchers at the Centers for Disease Control and Prevention, was published online Nov. 1 in the Journal of Food Protection.

Using CDC’s Foodborne Disease Outbreak Surveillance System, researchers identified 18 outbreaks between 1992 and 2014 that were reportedly caused by organic food products. These outbreaks were linked to 779 illnesses, 258 hospitalizations and three deaths.

More than half of the total outbreaks, 56 percent, occurred from 2010-2014, which the study authors note reflects the increasing production and consumption of organically grown food in the United States and around the world. Nine of the outbreaks occurred in a single state, while nine were multistate.

The most commonly occurring pathogens were Salmonella, responsible for 44 percent of the outbreaks, and E. coli O157:H7, the pathogen in 33 percent of the outbreaks, according to the study. Campylobacter, Clostridium botulinum and the Hepatitis A virus caused one outbreak each.

Eight of the 18 outbreaks were attributed to produce items, four to unpasteurized dairy products, two to eggs, two to nut and seed products, and two to multi-ingredient foods. Fifteen of the 18 outbreaks were associated with foods that were definitely or likely U.S. Department of Agriculture-certified as organic.

“Consumer perception often credits organic foods as being safer than conventionally produced foods, although organic standards do not directly address safety issues such as microbial or chemical hazards,” according to the study abstract.

The term “organic” had no official definition until 2000 when USDA’s National Organic Program standards were published, said Sam Crowe, epidemiologist and team lead for CDC’s National Outbreak Reporting System.

“So foods described as ‘organic’ before that time may not mean the same thing as it does now,” he told Food Safety News.

Crowe said information about how food is produced, whether conventional or organic, is not systematically collected through the National Outbreak Reporting System (NORS) and therefore it’s difficult to compare outbreaks linked to differing production methods.

“The authors had to search each outbreak report from 1973, when CDC began collecting information on foodborne outbreaks, through 2014 for any mention of the word ‘organic’ in order to identify organic food outbreaks,” he said.

“Some additional outbreaks could have been from food that was organically grown but not listed as such in the outbreak report. So we cannot say for sure how many outbreaks were from conventionally grown foods.”

Because of this current lack of regular data collection, the CDC researchers couldn’t pin down the relative risk of foodborne illness.

“We are unable to assess risk of outbreaks due to organic foods compared with conventional foods because foodborne outbreak surveillance does not systematically collect food production method,” the study states.

Crowe acknowledged there may be benefits to collecting information on how foods associated with outbreaks were grown. However, he added that local and state health department outbreak investigators are often responsible for collecting it during outbreak investigations, and that it is frequently not readily available.

“These investigators already have a tremendous amount of responsibility and local and state health departments are often understaffed and underfunded, so the additional burden would need to be assessed to determine whether or not this information is worth adding to the long list of requirements,” he said.

“At this time, CDC does not have plans to change the outbreak reporting system to capture this information, but nevertheless will continue to explore ways to improve outbreak reporting.”

Despite the paucity of consistent and relevant data, the researchers did offer some recommendations for consumers who want to avoid being sickened by foodborne pathogens, whether their foods of choice are organic or conventional.

“Consumers should be aware of the risk of milk and produce consumed raw, including organic,” they wrote. “Consumers should not assume organic foods to be more or less safe than foods produced by conventional methods. Proper handling, preparation, and storage of foods, regardless of production method, are necessary to prevent foodborne illness.”

The authors were R. Reid Harvey, Christine M. Zakhour and L. Hannah Gould, who were all with CDC’s Division of Foodborne, Waterborne, and Environmental Diseases at the time of the study.

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