How GMO labeling impacts vegetable purchases

Consumers were more willing to buy unlabeled produce after being shown food tagged as “genetically modified” in a new Cornell study that comes two months before a new federal food-labeling law goes into effect.

The research, “Signaling Impacts of GMO Labeling on Fruit and Vegetable Demand,” published online Oct. 30 in the journal PLOS One.

The study comes as food marketers prepare for a new federal law requiring genetically modified organism disclosure labels on food products beginning Jan. 1, 2020.

“We wanted to learn from consumers what will happen to conventional products when the labeling goes into effect and we start seeing ‘GM’ and ‘non-GM’ labeled produce at the market,” said co-author Miguel Gómez, associate professor at Cornell’s Charles H. Dyson School of Applied Economics and Management. “Will shoppers be willing to purchase a product when the new labels are introduced?”

Consumer aversion toward genetically modified food has inspired mandatory labeling proposals and laws at the state and federal levels, according to the paper. On Jan. 1, the U.S. Department of Agriculture will begin implementing the National Bioengineered Food Disclosure Standard, which requires food marketers to disclose the use of GMOs in food and food products.

In the study, the Cornell researchers recruited 1,300 consumers, who were shown GM, non-GM and unlabeled opportunities – in random sequences – to purchase apples, as well as other fruits and vegetables.

The paper found that when an unlabeled apple was presented first, the initial consumer demand – willingness to purchase – was 65.2%. But if the unlabeled apple was presented after participants saw an apple with a GM label, the demand for the unlabeled apple jumped to 77.7%.

If a consumer was presented first with an apple labeled “non-genetically modified,” the shopper’s preference for it was 67.2% – statistically even with the shopper initial preference for an unlabeled apple. “In other words, the ‘non-GM’ label is not stigmatizing the unlabeled product,” Gómez said.

The findings contradicted the experience of dairy farmers in the mid-1990s, who began using recombinant bovine somatotropin (rBST) – a growth hormone for cows – to increase milk production. Consumers soon demanded milk free from rBST, so dairies began to label milk as rBST-free on cartons. In doing so, it stigmatized regular milk as shoppers assumed that it contained rBST.

“Since milk was labeled as rBST free, sales of non-labeled milk declined,” Gómez said.

“We were pretty surprised when we first saw this paper’s results,” said co-author Adeline Yeh, a Cornell doctoral student in applied economics. “Our original hypothesis was that having a non-GM label would have a stigmatizing effect on the [unlabeled] fresh product. The results contradicted our original hypothesis. Instead, we found that the GMO label had a halo effect on the unlabeled product.”

Joining Gómez and Yeh as a co-author on the paper was Harry Kaiser, the Gellert Family Professor of Applied Economics and Management and associate dean of academic affairs for the Cornell SC Johnson College of Business. Gómez and Kaiser also are fellows at the Cornell Atkinson Center for Sustainability.

–  Blaine Friedlander, Cornell University