Organic Food Has 'Significantly Higher' Contamination, Study Finds

Marc Morano | July 7, 2008 | 8:21pm EDT
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( - A new study on food safety reveals that organic produce may contain a significantly higher risk of fecal contamination than conventionally grown produce.

A recent comparative analysis of organic produce versus conventional produce from the University of Minnesota shows that the organically grown produce had 9.7 percent positive samples for the presence of generic E. coli bacteria versus only 1.6 percent for conventional produce on farms in Minnesota.

The study, which was published in May in the Journal of Food Protection, concluded, "the observation that the prevalence of E. coli was significantly higher in organic produce supports the idea that organic produce is more susceptible to fecal contamination."

In addition, the study found the food-borne disease pathogen salmonella only on the organic produce samples. There was no evidence found of the deadly strain of bacteria, E. coli O157:H7, in either type of produce tested. The study looked at fruits and vegetables at the "preharvest" stage, not at the retail store level.

The principle investigator of the University of Minnesota study, Francisco Diez-Gonzalez, told that "organic agriculture was more susceptible to carry fecal indicators."

"In many ways it is confirming what is believed, indeed, if you are using animal manure for fertilizer, the chances that you are going to get fecal bacteria on the product are greater," Diez-Gonzalez said.

The higher incidences of fecal contamination in organic foods were linked to heavy reliance on composted animal manure for fertilizer. While conventionally grown produce may use some manure, it chiefly relies on chemical fertilizers. Past research has shown that Animal manure is the principal source of pathogens such as salmonella, campylobacter, and E. coli 0157:H7

But Diez-Gonzalez cautioned that his study does not show organic produce to be a higher risk food choice. "What the data is telling organic agriculture is there is some room for improvement," Diez-Gonzalez said.

"I don't think we need to be more concerned about organic vegetables. Based on the epidemiological evidence, we can say that both organic and conventional vegetables would pose the same [food borne pathogen] risk for consumers," he added.

But Diez-Gonzalez did acknowledge that a higher presence of generic E. coli could mean higher risk for deadly pathogens."We use E. coli as indicator that the potential could be there [for food borne pathogens]," Diez-Gonzalez explained.

Asked about how consumers -- who buy organic food for health reasons -- will react to his study showing higher fecal contamination, Diez-Gonzalez responded, "The consumer perception may not be very favorable and that is a potential consequence."

'Facade is crumbling'

Alex Avery, director of research and education at the free-market Hudson Institute's Center for Global Food Issues, says the latest scientific study confirms years of research that organic produce may pose a higher risk for food-borne illness.

"Organic food activists, which include many activist researchers entrenched in liberal university halls, have claimed organic food superiority for years in their efforts to mold society and scare consumers into buying their politically correct fare. Now their farcical facade is crumbling," Avery told

Avery was particularly concerned about a possibly elevated risk for pathogens such as salmonella and the deadly E. coli O157:H7 in organic produce. E. coli O157:H7 can attack the kidneys and liver, causing severe internal damage and even death, especially among the elderly and young children.

Avery called the risk of contracting salmonella from organic food a "crap shoot," with the pay off being "diarrhea, typhoid fever, and Reiter's Syndrome that causes joint pain and painful urination that can last for years after the initial salmonella infection."

The University of Minnesota study found salmonella in one sample of organic lettuce and one sample of organic green peppers. The researchers collected 476 Minnesota produce samples from 32 organic farms and 129 samples from eight conventional farms. The produce analyzed included unwashed tomatoes, lettuce, green peppers, cucumbers, broccoli, apples, and strawberries.

The study reported that "an increasing number of gastrointestinal disease outbreaks have been linked to the consumption of fresh fruits and vegetables," accounting for a total of 148 outbreaks between 1990 and 2001.

The study found organic lettuce had the highest rate of fecal contamination, with a rate of over 22 percent. And Avery says consumers can't assume they can simply "wash off" the fecal matter from the lettuce.

"Past research shows that E. coli 0157 can enter into the lettuce through the roots and be inside the lettuce, meaning you can't wash it off," Avery said.

Organic: 'Most especially at risk'

The controversy over the safety of organic food began in 1997, when Robert Tauxe, chief of the food-borne illness division of the Centers for Disease Control, addressed pathogens that thrive in manure. Tauxe was quoted in the Journal of the American Medical Association as saying, "Organic means a food was grown in animal manure."

The article in the 1997 Journal of the American Medical Association implicated "organically grown, unprocessed foods produced without... pesticides or preservatives" as an increasing source of food-borne illness.

The nationally syndicated television news program American Investigator also quoted the Food and Drug Administration's Virlie Walker as warning Americans that, "Most especially at risk [for food borne pathogens] are your organic products because they could be fertilized with manure."

Walker, the spokesperson for the FDA's Denver district, told the news program in June 1998, "We do encourage folks to pay special attention to cleaning their organic products."

In 2000, ABC's John Stossel, followed up with a similar television report on 20/20 about the potential bacterial dangers of organic produce.

Diez-Gonzalez believes his findings of increased fecal contamination in organic food will not surprise consumers "if they have been following the media [reports]."

"Most likely, [our study] is going to serve to prove that some in media were right in terms of the E. coli, the fecal contamination, but not in terms of pathogens," Diez-Gonzalez said.

'Lightening rod for public officials'

Avery sees the issue of organic food politics as being too hot to handle for most food regulators.

"Organic food production has become a lightening rod for public officials. The CDC does not want to touch this with a ten foot pole," Avery said.

Referring to the CDC's Tauxe -- and his comments about organic food in 1997 -- Avery said the organic lobby "went ballistic and inundated the CDC with phone calls."

"This research continues to raise the red flags that have been raised in the past by credible food safety experts like Tauxe at the CDC. How many red flags have to be raised in order to get stricter manure regulations?" Avery asked.

Avery also believes that the driving force behind organic produce, the fear of chemical pesticides, is completely unwarranted.

"The National Research Council, an arm of the National Academy of Sciences, found in 1999 that the cancer risk from pesticide residue is theoretically lower than the risk from naturally occurring carcinogens. Both types are too low to be appreciable cancer risks," Avery explained.

"We are still looking for the first cancer death victim from pesticide residues. But we have several examples of children killed by pathogenic bacteria on organic produce," he added.

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