Several big food and beverage companies are looking at a new ingredient in the battle for health-conscious consumers: a chemical that tricks the taste buds into sensing sugar or salt even when it is not there.

Kraft Foods, Nestlé, Coca-Cola and Campbell Soup are all working with a biotechnology company called Senomyx, which has developed several chemicals, most of which do not have any flavor of their own but instead work by activating or blocking receptors in the mouth that are responsible for taste. They can enhance or replicate the taste of sugar, salt and monosodium glutamate, or MSG, in foods.

By adding one of Senomyx’s flavorings to their products, manufacturers can, for instance, reduce the sugar in a cookie or salt in a can of soup by one-third to one-half while retaining the same sweetness or saltiness.
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Unlike artificial sweeteners, Senomyx’s chemical compounds will not be listed separately on ingredient labels. Instead, they will be lumped into a broad category - “artificial flavors” - already found on most packaged food labels.
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Executives say that a taste receptor or family of receptors on the tongue or in the mouth are responsible for recognizing a taste. Using the human genome sequence, the company says, it has identified hundreds of those taste receptors. Its chemical compounds activate the receptors in a way that accentuates the taste of sugar or salt. It is still experimenting to determine the most potent compounds, its chief scientist, Mark Zoller, said.

While food safety experts applaud efforts to reduce salt, MSG and sugar, they expressed concerns about the new chemicals, saying that more testing needed to be done before these were sold in food.

But Senomyx maintains that its new products are safe because they will be used in tiny quantities.
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Since Senomyx’s flavor compounds will be used in small proportions (less than one part per million), the company is able to bypass the lengthy F.D.A. approval process required to get food additives on the market. Getting the Flavor and Extract Manufacturers Association status of generally recognized as safe, or GRAS, took Senomyx less than 18 months, including a 3-month safety study using rats. In contrast, the maker of the artificial sweetener sucralose spent 11 years winning F.D.A. approval and is required to list the ingredient on food labels.

Michael Jacobson, executive director of the Center for Science in the Public Interest, endorsed Senomyx’s ability to reduce salt, sugar and MSG, but cautioned against a new chemical entering the food supply without rigorous testing. “A three-month study is completely inadequate,” he said. “What you want is at least a two-year study on several species of animals.”

Senomyx responded that in contrast to artificial sweeteners, which are used at levels of 200 to 500 parts per million, its flavorings would be added in such small quantities that they would pose no safety risk. These low-use levels are also what allow Senomyx’s chemicals to be classified as artificial flavors.