As food manufacturers move away from expiration dates and use "best if used by" dates on foods instead, research shows that consumers turn their noses up as the "best if used by" date approaches -- and not because of the food's perceived safety. Researchers asked 36 panelists to evaluate different types of yogurt with various "best if used by" dates, but no mention was made of the dates.

"We found that as the expiration dates approached or went by, the panelists' acceptance of the food diminished, as did their perceptions of the food's healthfulness and freshness," said Brian Wansink, a Cornell professor of marketing and of nutritional sciences, who conducted the study with Alan Wright, director of the U.S. Army Natick Soldier Center's sensory laboratory. "It appears that it's the food's perceived freshness rather than its safety that is the driving factor."

Foods labeled as fresh were not rated any more acceptable than those without a freshness label.

Wansink said that the results imply there may be more for a manufacturer to lose than to gain by having decided to use "freshness dating" in the first place.

The study was published in the May issue of the Journal of Food Science (Vol. 71:4).