A U.N. panel on standards for food safety and labeling plans to ask makers to print data on the percentages by weight of certain ingredients in prepackaged foods on labels attached to the products, nongovernment organization sources said.

The Codex Alimentarius Commission — a panel of experts formed by both the World Health Organization and the Food and Agriculture Organization — will formalize a decision to devise data standards at a meeting in late June in Geneva.

Following this decision, a task force on labeling guidelines — the Committee on Food Labeling — will discuss the propriety of obliging makers to attach labels displaying weight-based percentages of ingredients in packaged foods, the sources said.

At present, most food makers worldwide print only the names of the ingredients used in producing certain multi-ingredient foods on their labels. It is rare for makers to voluntarily display the percentages of the ingredients they have used in packaged foods.

As an example, they said that most consumers are prevented from distinguishing “tomato sauce” made 100 percent from tomatoes from a more diluted product still described as “tomato sauce” by makers.

In responding to these labeling ambiguities, consumer groups in various countries have criticized food manufacturers for offering too little information on percentages of food ingredients in multi-ingredient foods.

The International Association of Consumer Food Organizations, a nongovernmental organization that has been an official observer at the Codex Alimentarius Commission, presented a set of proposals to stiffen disclosure guidelines on the labeling of such foods at a meeting of the Committee on Food Labeling in May.

In response, committee members from various countries agreed to consider tightening the guidelines by discussing the IACFO proposals.

The proposals call for displaying the exact percentages of all ingredients accounting for more than 5 percent of packaged foods on a weight basis on a label attached to the product.

Citing another example of a packaged “strawberry yogurt,” the sources said the IACFO-proposed guidelines also call for conspicuously printing the percentage figure of strawberries by weight on the product if the maker opts to emphasize the product’s strawberry content by name or illustration.

The guidelines will not be legally binding but are likely to become global standards and motivate governments to devise domestic laws based on them once they are adopted by the Codex Alimentarius Commission, they said.