Eating organic may limit your exposure to pesticides. It may make you feel environmentally conscious. It can help support local farmers.

But scientists warn it won’t necessarily protect you against foodborne illnesses. Organics, like conventionally farmed foods, can harbor dangerous pathogens including E. coli and salmonella.

A 2006 study in the Journal of Food Science did not find a significant difference in the prevalence of E. coli between organic and conventional produce. And a 2009 Kansas State University study did not find a difference in the prevalence of E. coli between organically and conventionally raised cattle.

Organic foods have caused their share of outbreaks of disease. Last winter, for example, sprouts from an organic farm in Illinois infected at least 140 people in 26 states and the District of Columbia with salmonella. And over a three-month period in 2011, a massive outbreak of a deadly strain of E. coli linked to sprouts from an organic farm in Germany killed 50 people and sickened more than 4,300 in several countries.

Organics are a big business in the U.S. Sales of organic food and beverages totaled $26.7 billion in 2010, according to the Organic Trade Association, with sales of fruits and vegetables up nearly 12 percent over 2009.

Consumers buy organic for a number of reasons, including to avoid certain pesticides, to encourage smaller farms and to support agriculture that doesn’t introduce harsh substances into the environment. In a June 2011 health survey by Thomson Reuters and National Public Radio, 58 percent of respondents said they preferred organic over nonorganic foods. The most popular reasons cited: to avoid toxins and support local farmers.

Despite the public’s favorable perceptions, however, “the science doesn’t show a difference,” said David Lineback, senior fellow in food safety at the Joint Institute for Food Safety and Applied Nutrition at the University of Maryland.

Federal organic standards set by the U.S. Department of Agriculture do not include explicit requirements for food safety, nor are they intended to. The primary purpose of organic farming is not to prevent foodborne illness but to practice and promote environmentally sustainable agriculture.

“We don’t purport that organic is healthier than conventional food,” said USDA spokeswoman Soo Kim.

“The organic standards do not directly address issues of food safety but instead production and processing and handling methods of agricultural products,” Kim said in an email. But, she added, “organic certification by the USDA doesn’t preclude any operation from having to meet the food safety and environmental requirements” of two other federal bodies: the U.S. Food and Drug Administration and the Environmental Protection Agency.

Organic labeling standards are based on the percentage of organic ingredients in a product.

For crops, this means growing on land without the application of any prohibited substances (as defined in the Organic Foods Production Act of 1990) and without the use of genetically modified organisms, most conventional pesticides or sewage sludge, for example. Organic livestock must be raised without hormones, fed 100 percent organic feed without byproducts and given year-round access to the outdoors.

Organic Sprout House from News21 on Vimeo.

Amy Annable, 28, Sprout Operations Manager at Edrich Farms in Randallstown, MA discusses sprout safety.

Carrie Vaughn, vegetable production manager of the recently certified organic Clagett Farm in Upper Marlboro, Md., said she believes the food safety risks are lower on her farm because of strict standards for manure composting that come with organic certification.

USDA’s organic program requires composted manure to be heated to at least 131 F for a minimum of either three or 15 days (depending on the composting system) in order to reduce pathogens.

Vaughn said the close relationship she has with her buyers and their families motivates her to be vigilant about food safety in the field. “It’s terrifying for me as a grower to think that I could grow something that could kill a small child,” she said. “So we’re careful on the farm, and we also work directly with our customers. … If something ever happened, it would be so easy to trace that contamination back to us.”

Lineback, at JIFSAN, remains skeptical of what he calls consumers’ “I-know-the-farmer” attitude. That trust, he said, is rooted not in science but in consumers’ feelings about food and a distrust of corporate agriculture.

There is even debate over whether organic food is more nutritious, as proponents maintain. The American Journal of Clinical Nutrition reported in 2010 that a study of 50 years of academic articles on the topic found that organic and conventional foods are nutritionally comparable.

So, which is better for you: organic or conventional? In the end, as Lineback noted, “it’s a matter of choice and what people believe.”

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Madhu Rajaraman wrote this story while a Carnegie-Knight News21 fellow from Maryland. The story was part of the “How Safe is Your Food?” project of News21, a program of the Carnegie Corporation of New York and the John S. and James L. Knight Foundation to foster in-depth, interactive and innovative investigative journalism at journalism schools across the country. It is headquartered at Arizona State University’s Walter Cronkite School of Journalism and Mass Communication. Republished with permission.