Organics Under the Microscope

A recent study by University of Minnesota researchers seems to cast doubt on the safety of organic food, but confusing terminology and problems with how raw data was gathered earn mixed marks for the study itself.

This important, groundbreaking study, published in May's Journal of Food Protection, examined the potential for disease-causing bacteria and fecal contamination in conventionally-grown, certified-organic, and uncertified-organic Minnesota produce.

While the results showed that all three categories of produce had a low potential for E. coli contamination, the results were decidedly mixed for organic produce.

What does this mean for organic consumers? Not much, according to the study's senior co-author, Francisco Diez-Gonzalez. He says the study deliberately looked at produce that had not been washed, disinfected, or undergone any "post-harvest handling."

"If consumers read this study," Diez-Gonzalez told The Wedge Newsletter, "they should take it with a grain of salt, since we weren't looking at what consumers actually eat."

Diez-Gonzalez, Assistant Professor in Food Safety Microbiology at the U, says the study is primarily for farmers who want to improve their practices.

There's good news and bad news for organic farming practices, according to Diez-Gonzalez and his colleagues.

On one hand, higher instances of E. coli and fecal contamination were found in both categories of "organic" produce. On the other hand, certified-organic produce had 2.6 times less chance for contamination than uncertified organic produce.

This earned praise for certified-organic practices from the team of food scientists and agronomists who concluded that there exists "a potential association between organic certification and reduced E. coli prevalence." They said it warranted further research.

Meanwhile, the deadly variety of E. Coli, with the catchy name O157:H7, can be devastating to humans, but it wasn't found in any of the samples examined by the U of M. While reduced E. coli prevalence generally means fewer food-borne illnesses, consumers should note that E. coli describes an array of microbes, the vast majority of which are important to composting and fertilization in agriculture. These microbes can also hitch a ride in the digestive tracts of warm-blooded animals without sickening them.

Nevertheless, the study did find troubling evidence of another microbe in the organic samples. Salmonella was found on one green pepper and one head of lettuce from two different organic farms. Salmonella can cause diarrhea, fever, and abdominal cramps, and in rare instances, death if untreated with antibiotics.

Sadly, the study suffers from a crucial lapse in exactness here. It claims that the Salmonella-tainted produce came from "organic farms," without specifying whether the farms were certified or uncertified. A recent call to Dr. Diez-Gonzalez clarified that the Salmonella was isolated from uncertified organic farms.

That's a big detail to leave out. As most natural foods shoppers know, "certified organic" and "organic" are as different as lightning and lightning bugs.

In a study that otherwise validates the safety of certified organic farming practices, it's unfortunate that it suddenly blurs its own definitions of organic.

To avoid such blurriness, the USDA has written very clear rules about the use of the word organic: Only product grown with strict organic practices and certified by an accredited certifier can be called "certified organic." There is no category "uncertified organic" according to the USDA. The accepted term for product that has not been certified organic is conventional.

Thus, if a USDA official were looking at the U of M study's uncertified lettuce, she would say it came from a conventional farm, not an "organic" farm, and furthermore, she would tabulate all uncertified-organic and conventional samples together. Had this study adhered to USDA terminology, its results would have more accruately reflected industry standards and, interestingly enough, would have found higher prevalences of E. coli on conventional farms.

The main reason for clearly defining conventional from organic farming is to verify practices and claims. This, too, is problematic in the U of M study. How sure were researchers that farmers followed organic practices on uncertified, un-inspected farms? "We were not one-hundred percent sure," said Diez-Gonzalez.

In a way, it's understandable why the U of M team was forced to seek samples from uncertified farms, since certified organic farmers were reticent to lend involvement. They feared a contrary, political agenda behind the study since the organic industry had been burned many times before. "So yes, we had a skewed population of farmers, unfortunately," said Diez-Gonzalez.

For the same reasons, U of M researchers also had a hard time finding organic and conventional farms of consistent and similar size. The average "organic" farm was 10 acres - quite small. The average conventional farm sampled was twice as large and included one 200-acre farm. Whether conventional or certified-organic, larger farms net larger incomes and have more sophisticated means to protect against contamination at their disposal.

"That also is one of the weaknesses of the study," Diez-Gonzalez said, "the imbalance of farm size."

As a good scientist should, Dr. Diez-Gonzalez speaks about the study's shortcomings without hesitation. Indeed, he believes the study, ongoing in its second year, has improved with a more balanced population this season. "We already have more farms, more certified versus conventional this year."

He also hopes that he can further examine more specific contamination issues facing farmers. On farms with a high prevalence of E. coli, for example, Diez-Gonzalez would like to conduct "trace-back" studies, which would examine soil, water, and other factors leading to microbial tainting. Conversely, he'd like to see trace-backs of certified organic practices in order to determine what aspects of their fertilization and composting techniques lessen the potential for contamination.

That, ultimately, is the goal of his team's work - good data for farmers to create better practices for safer foods. "We would like to be able to identify practices that are beneficial to farmers," he says. "Food safety is a pressing issue in these times."