The US Food and Drug Administration letter, dated May 31, 2006, gives Masterfoods USA 15 days from the time of receipt to inform the federal agency of its plans to comply.
CocoaVia products, launched at retail in October, have been heavily marketed as 'healthy'.
The firm's chief scientist Dr Harold Schmitz has previously said:"CocoaVia is the vanguard of our efforts to 'reinvent' cocoa as an ingredient in healthful foods."
Mars, the division under which CocoVia falls, has set up a new business unit to promote its healthy range called Mars Nutrition for Health & Well-Being. Its brief is to target consumers who are aware of the need to switch to healthier foods but reluctant to change eating habits and pass on chocolate bars.
The move into the health and nutrition area is also part of its continuing portfolio diversification, as Mars now offers savory snacks, pet food, and food and beverages other than chocolate.
But by the FDA's reckoning, the initiative pushes the definition of what constitutes a food or drug under US law.
"Articles intended for use in the diagnosis, cure, mitigation, treatment or prevention of disease in man are drugs under section 201(g)(1)(B)of the Act," wrote Joseph Baca, director of the office of compliance for the Center for Food Safety and Applied Nutrition, in the letter.
And according to federal regulation, drugs, unlike foods, require pre-market approval - which means Masterfoods may face changing its entire marketing approach to CocoaViva.
Baca describes the product line as "misbranded" in the letter, condemning the functional chocolate bars' health claims, which include "Promotes a healthy heart" and "Now you can have real chocolate pleasure with real heart health benefits".
"These claims are false or misleading because of the high levels of saturated fat in the products," warns the letter, which was addressed to Masterfoods vice president of research and development John Helferich.
The healthy CocoaVia image is based on the bars' high content of cocoa flavonols, powerful antioxidants. But the plant sterol/stanol esters the product line contained provide the basis on which it makes heart health claims.
However, the letter states these claims are only authorized when the food is also low in saturated fats. This is not the case with CocoaVia products which, according to the FDA, contain one-third the daily value for saturated fat (20grams) per recommended serving.
The FDA is also at odds with the ingredient folic acid, citing that food additive regulation (21 CFF 172.345) does not provide for adding folic acid to candy products, which the agency says is designed to keep total folic acid intake to under 1mg per day.
"The consumption of higher levels of folic acid can mask anemia in persons with vitamin B 12 deficiency," Baca explained.
The CocoaVia line includes the Chocolate Blueberry Crunch Bar, and Blueberry & Almond Chocolate Bars, both of which contain folic acid, which the FDA deemed "unsafe" on the grounds that it may cause consumers to inadvertently consume more than the recommended upper limit of 1mg. in the letter.
The US does have a policy of mandatory fortification of grain products with folic acid, which was introduced in 1998 in a bid to reduce the number of pregnancies affected by neural tube defects.
This measure has been hailed as a success - since its introduction birth defects in the US have decreased by 26 percent. However some other countries have held off from mandatory folic acid fortification of grains on the grounds that it may mask detection of vitamin B12 deficiency in eldery people.
The level of folic acid fortification in grain products is set at 140 micrograms of folic acid per 100 grams of grain (across all grain products, including bread, pasta, cereal, rice and flour). But some campaigners have recently been calling for an increase in levels to 280 or even 350 micrograms per 100 grams.
The company had not responded to NutraIngredients-USA.com's request for a comment prior to publication.