Recent concerns with food safety have led to a number of products featuring 'freshness dating', a variation of expiration dating, as a form of guarantee of food quality.
But according to a study by researchers at Cornell University, this may be damaging their product more than it is promoting it.
"Manufacturers need to realize that freshness ratings may not only influence whether a person buys a food, but they can also influence what a person thinks of a food after it has been bought," write the researchers in a recent issue of the Journal of Food Science.
Their study reveals that freshness dating, or 'best if used by' dating, influences peoples' taste perception, as well as their perceptions of the product's freshness and its healthfulness.
On the other hand, this kind of dating has no effect on perceptions of food safety, said the researchers.
"This is important because it indicates that efforts to use freshness dating to connote safety or risk would be misdirected," they said.
The study involved 36 consumers between the ages of 25 and 62, who were given five different yogurt products to taste, two of which were target products while the remaining three were distracter, or filler, items.
The yogurt samples were identified with freshness dating that indicated they were either one month from expiration, one day from expiration, one day past expiration or one month past expiration. The fifth sample had no expiration date. In reality, all yogurt samples were equally fresh and were more than 30 days ahead of their actual expiration date.
Each participant was then asked to rate the degree to which the two target yogurts were acceptable, fresh, safe, healthful and risky.
The results revealed that as the freshness date nears expiration, there was a decreased acceptance of the food, as well as a decreased perception of its healthfulness and its freshness. However, this change in freshness dating was not found to have a significant impact on the risk associated with the food.
The researchers noted, however, that one limitation to their study method was that the products were presented to participants in a controlled sensory lab, which may have led people to assume the products were safe because of liability reasons. This could have contributed to people not identifying expiration dates with product risk and safety.
The biggest decline in perceptions of a food was found to be between foods believed to be 30 days fresh and one day fresh. And a product that was even one day past being dated as fresh was significantly degenerated in its acceptability.
However, a product labeled as fresh was not significantly more acceptable than one that was unlabeled, the study found.
"People generally taste what they expect to taste," said the study, citing previous research that found that labeling can lead to people to taste labeled ingredients, such as soy, that are not present.
"Unless freshness dating is a source of positioning, as it recently appears to be with soft drinks and beers, such dating appears more likely to hurt than to help a product," concluded the study.