It’s not a first: GE labeled corn sells better than non-GE is reporting that the Avila Valley Barn in San Luis, Calif., clearly labels sweet corn it sells as genetically engineered — “Our own GE corn" — and offers customers a choice of traditional corn.

“People have the right to know what they are eating,” DeVincenzo said.

Couldn’t agree more. Consumer right to know is a fundamental value for North American shoppers. Labels may not be the best way to provide such information.

Andrew Christie, director of the local chapter of the Sierra Club, said,

“We still don’t think enough testing has been done on GE crops, but failing that, GE products should be labeled. We heartily endorse the precedent Dr. DeVincenzo is setting."

The store offers the GE and traditional corn at the same price.

While some customers complained that GE corn was offered at all, DeVincenzo said the typical customer says they prefer the modified type because it is not shucked and looks fresher. Traditional corn has to be partially or completely shucked to eliminate ears that are infested with worms.

Contrary to what the story says, it’s not a first, to have genetically engineered and conventional whole produce sold side-by-side. Jeff Wilson of Birkbank Farms in Ontario, and my gang, did this beginning in 2000. We published the results in the British Food Journal in 2003 (Powell, D.A., Blaine, K., Morris, S. and Wilson, J. (2003), “Agronomic and consumer considerations for Bt and conventional sweet-corn”, British Food Journal, Vol. 105 No. 10, pp. 700-13.), and won best paper for the year.

People have been complaining ever since, and making a lot of accusations about me and the research.

In response, this is what I published, again in the British Food Journal, Aug, 1, 2006 (Vol  108 Issue 8).

Would you eat wormy sweet corn? Or cabbage? Or broccoli?

That is what Ontario, Canada, producer Jeff Wilson often asks his customers. With 200 acres of fresh fruit and vegetables and a retail market on the farm, inquiring about his customers’ preferences is not just good manners, it is good business.

Throughout the 1990s, Wilson’s customers expressed a desire for reduced pesticides in the fresh produce purchased at his Birkbank Farms market. Wilson adopted an intensive integrated pest management program, but when cool, wet weather struck in 1997 – ideal for European corn borer – many of Wilson’s customers who had previously said they could tolerate wormy corn by breaking off the damaged ends were no where to be found.

Wilson lost about $25,000 on sweet corn sales that year; an expensive lesson in people say one thing, but when it comes to grocery shopping, often do another.

So when I approached Jeff Wilson in 1999 about growing a genetically engineered Bt-sweet corn that in Florida field-trials had significantly reduced the need for pesticide sprays to control corn borer, he was enthusiastic.

I was eager to see what consumers would do when given a choice between genetically engineered and conventional whole produce – in this case sweet corn and potatoes – in a market setting instead of a survey or willingness to pay experiment which are both notoriously misleading.

As described in our paper (Powell et al., 2003), conventional (what we labeled as “regular” based on customer feedback) and genetically engineered Bt-sweet corn and potatoes were grown in similar eight acre plots, harvested, segregated and made available for sale at the Birkbank Farms Market.

Joe Cummins, and others on the Internet, have accused me, and my co-investigators, of academic fraud and bias, because a sign sitting atop the bin of regular sweet corn asked, Would you eat wormy sweet corn?

That is a question Jeff Wilson cares about, with his pocketbook. It is also the language consumers use when talking about sweet corn, and what they are looking for when they peel back the silks of corn-on-the-cob.

But is it language intended to manipulate consumer purchasing patterns?


The use of language, and its shared meaning, is always subjective. I have always based such work on the integrative risk analysis framework, first promoted by the US Presidential/Congressional Commission on Risk Assessment and Risk Management in 1997 (available at: which argues that risk assessment, management and communication activities should be intertwined and reciprocal, rather than separate entities. And the best way to deal with value judgments in risk analysis is to openly declare potential sources of bias.

My bias is that science has a responsibility to lead, to explore the use of new technologies to enhance the safety and quality of the food supply while actively minimizing risks and respecting the concerns of affected consumers. For over a decade I have devoted my career to reducing the incidence of foodborne illness, and to the responsible use of new technologies to enhance the safety of the food supply.

Wilson and his staff at Birkbank Farms are committed to providing consumers with high quality food produced in the safest manner, as well as clear and accessible information regarding how that food is produced. Our shared goal is to understand consumer preference, not shape it.

The point-of-sale information in 2000 (and in subsequent years not described in Powell et al., 2003) at Birkbank Farms consisted of a large placard describing the options Wilson had to produce non-wormy corn, smaller handwritten signs describing the treatments received by corn available for sale on a specific day (which varied weekly throughout the course of the six-week consumer data collection period to reflect the different conditions under which different rows of corn were grown and variations in weather) and information pamphlets. This presentation can be viewed at:

The large placard contained the following text:

“Delivering High Quality Sweet Corn
In order to provide you with the quality of sweet corn that you want we have three options
1. Genetically engineered Bt-sweet corn:
contains Bt protein in leaves and stalk; and requires fewer insecticides to prevent worm damage thus minimizing environmental impact.
2. Bt-spary
same Bt protein as in genetically engineered variety but sprayed on leaves; and
protein exists naturally in environment and breaks down rapidly …
3. Conventional pesticides:
used by most farmers to create worm free corn; and
applied according to guidelines set by governments, but harm to beneficial insects observed”.

Because the work at Birkbank Farms was an overall risk analysis experiment in providing the public, and anyone else, with full and transparent information about how a particular commodity was produced, a press conference was held at Birrkbank Farms on 30 August 2000, to mark the beginning of the sweet corn harvest. The handwritten sign over the regular sweet corn asked, Would you eat wormy sweet corn, and then listed the treatments that corn had received to produce less-wormy sweet corn. The handwritten sign over the GE sweet corn (and we deliberately chose the label GE sweet corn because that is what it was – not just genetically modified, not a product of biotechnology or other terms that proponents of GE have suggested may be more palatable to the consuming public) said “Here’s what went into producing quality sweet corn”, and listed no pesticides but herbicide and fertilizer. The handwritten signs were changed the following week.

A critic of GE may charge that simply asking the question, Would you eat wormy sweet corn, unduly influences consumer preference. A supporter of GE may charge that by labelling the corn genetically engineered unduly stigmatises the product and influences consumer preference (Powell, 2001).

I find such categorizations simplistic.

However, one journalist, among the dozens of other journalists, scientists, activists and hundreds of consumers who visited Birkbank Farms during the data collection period, and cited by Cummins, apparently interpreted the sign as evidence of manipulation.

We observed no evidence to support that charge, either through formal intercept interviews or anecdotal conversations; quite simply, no one else mentioned the wormy corn aspect of our signage (which was referred to in the description on the placard and, briefly, on the handwritten sign), although we admittedly did not specifically ask the question. What we did observe and respond to was heightened customer interest in methods of food production generally, and in response we developed and maintained a three kilometre self-guided walking tour on Birkbank Farms outlining the various tradeoffs and choices that face a commercial producer. Hundreds of people who wanted to know more about how their food was produced and the challenges involved took a stroll through the farm in 2000, and hundreds more in subsequent years.

In 2001, when we deliberately downplayed the research at the farm after the extensive media attention the previous year, sales of GE sweet corn outsold regular sweet corn 5:2. The presentation used that year is available at: = 4&c = 18&sc = 137&id = 889.

Cummins also alleges that the point-of-sale literature was promotional. The only literature that I am aware of present at point-of-sale was a brochure written by Katija Blaine and me, that contained information about benefits, risks and management strategies. Interested readers can make their own conclusions about the alleged persuasive nature of the brochures – one for Bt-sweet corn and one for Bt potatoes – by viewing them at: = 3&c = 9&sc = 53&id = 886 and = 3&c = 9&sc = 53&id = 887,respectively.

The research at Birkbank Farms had strengths and weaknesses and both were related to the commercial nature of Wilson’s operation. However, since May 2000 when we first wrote to Wilson’s neighbours to inform them of our intent and hosted a public meeting for others to voice their concerns, we have been completely open about our intentions and results, and welcomed criticisms as a way to improve the project.

Powell, et al. (2003) explicitly acknowledged the limitations and applicability of the research by stating, “The labels on the produce bins may have influenced consumers to buy, just because they were there or perhaps because there was detailed information provided”, and concluded, “This research is a starting-point and describes the experience of one farmer on one farm during the 2000 growing season”.

Finally, to suggest that I possess some extraordinary persuasive skills, and that if I did, I would influence sweet corn purchases, one buyer at a time (with an intercept interviewee who was not included in the study) says more about the preconceived notion of my critics. What some allege is manipulation could more readily be described as conversation. Talking to people is good for Jeff Wilson’s business and good for researchers.

Douglas Powell
Associate Professor, Department Diagnostic Medicine/Pathobiology, Kansas State University, Manhattan, KS, USA


Powell, D.A. (2001), “Mad cow disease and the stigmatization of British beef”, in Flynn, J., Slovic, P. and Kunreuther (Eds), Risk Media and Stigma, EarthScan, London, pp. 219-28.

Powell, D.A., Blaine, K., Morris, S. and Wilson, J. (2003), “Agronomic and consumer considerations for Bt and conventional sweet-corn”, British Food Journal, Vol. 105 No. 10, pp. 700-13.