The decision was based on the need to "prevent false and misleading food labeling statements," according to the FDA, which claimed that such terms would lead to consumer confusion on the implied nutrient content of whole grain foods.
The petition, filed in May last year, used fiber content as a way to determine the levels of whole grain present in foods, suggesting that 11.1g of fiber should be used as a marker for 100g of whole grain blend.
The petition stated that 'excellent source' of whole grain requires 16g or more per labeled serving, 'good source' requires 8-15g per labeled serving, and 'made with' requires at least 8g.
The terms would be neither nutrient content nor health claims, said General Mills, but the FDA was not convinced that confusion would be avoided.
"The use of such terms with whole grains would be considered to be implied nutrient content claims about the fiber in whole grains," said Margaret O'K Glavin, the FDA's associate commissioner for regulatory affairs in a letter to General Mills last month.
"'Excellent source' and 'good source' have been defined for use with nutrients that have an established reference daily intake (RDI) or daily reference value (DRV) in nutrient content claims. There is no RDI or DRV for whole grains," she added.
Additionally, the FDA said it needed to decide the appropriate classification of certain label statements - such as dietary guidance, nutrient content claims or health claims - before considering whether to publish a proposed rule for such statements.
It added that this classification also needs to include consideration of scientific evidence that suggests that the health benefits of whole grains are based on more than their fiber content.
Recent research has demonstrated how wholegrain foods can have a protective effect against heart disease, stroke and type 2 diabetes, findings that have resulted in growing numbers of consumers turning to whole grain rich foods, and manufacturers increasingly altering product formulations to cater for the health trend.
Whole grains are also said to keep weight down, as components within whole grains contribute to favorable metabolic alterations that may reduce long-term weight gain.
Although the FDA denied the petition by General Mills, it said it "acknowledges the need for action" on this issue.
"The recommendations from the recent Dietary Guidelines for Americans 2005 demonstrate that consumers can benefit from increased consumption of whole grains."
"We are reviewing options for public input on how to classify certain statements about food, including dietary guidance statements. Our review includes possible approaches on how to provide useful information to the public on whole grains. In addition, we are considering the development of guidance on what we consider the term 'whole grains' to include," concluded Glavin.