CORVALLIS - A new national survey of household shoppers has found that three out of four consumers are concerned about future discovery of adverse health effects from drinking milk from cows treated with synthetic hormones.

The survey was conducted by Robin Douthitt and Lydia Zepeda, faculty members at the University of Wisconsin, and Deana Grobe, a Ph.D. candidate in family resource management in the Department of Human Development and Family Sciences at Oregon State University.

Grobe said the study was designed to determine consumer attitudes on the use of biotechnology in food sources, in particular "recombinant bovine growth hormone," or rbGH, which is used in dairy cattle to increase milk production. The Food and Drug Administration approved the commercial use of rbGH nearly two years ago.

The study shows, however, that wary consumers are not exactly sold on the process. The survey of 1,900 people found that, while 53 percent approved of biotechnology, less than 12 percent believed food-related application of rbGH is a good or excellent idea, and 74 percent were moderately or very concerned about rbGH-related health risks that may be found in the future.

"About 64 percent of those surveyed were aware of rbGH; they had heard of it or knew something about it," Grobe said.

A synthetic form of a growth hormone naturally produced in the pituitary gland of cattle, rbGH can increase milk production by 25 percent. It has no other apparent effect on the milk.

"There is no difference in the appearance or the taste of milk that comes from cows treated with rbGH," Grobe said.

A lack of apparent benefits may be part of the problem, she pointed out.

The survey shows a much broader acceptance of a similar hormone, rpGH, which when injected into pigs is said to reduce the fat content of pork. Fifty percent said they would consider buying the leaner, but treated pork.

"It's a more tangible benefit," Grobe said.

The FDA has not yet approved the hormone rpGH.

Grobe did her undergraduate and master's studies at Wisconsin, working with Douthitt and Zepeda, both professors of consumer science. She conducted focus group sessions in Oregon to help design the survey and has continued those studies, basing her doctoral dissertation at OSU on the rbGH research.

The new survey also found that income also plays a role in consumer acceptance. Respondents who met USDA poverty guideline requirements were less aware of biotechnology and less likely to think using rbGH was a good idea.

Gender differences also exist. Men were more likely to be aware of biotechnology issues and rbGH, and gave them higher approval ratings, while women were more likely to prefer milk from untreated herds and were more concerned about future discovery of adverse health risks.

However, changes in consumer behavior relating to the use of synthetic hormones have been hard to track, the researchers pointed out. One idea which met with considerable approval involved labeling, Grobe said. About 94 percent of those surveyed said they approved of labels to differentiate milk from treated and untreated sources.

"There also is starting to be a tendency on the part of consumers to explore alternative sources of milk," Grobe said, "including soy milk, goat milk and organic milk from cows which have not been subjected to antibiotics or synthetic hormones."

More change may be on the horizon. When asked how, if at all, the approval of rbGH has influenced the amount of milk they buy, about 5.4 percent of those surveyed say they have decreased their milk consumption because of rbGH in only the first year since its FDA approval.

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Deana Grobe, 541-737-7719