WASHINGTONThe Center for Science in the Public Interest (CSPI) last week threatened to sue three different food companies if they didn't change their labels.

The healthy advocacy group demanded that Kraft Foods Group, Inc., remove the word "natural" from Crystal Light's "Natural" lemonade and iced tea mixes.

According to CSPI, the beverages contain several artificial ingredients like citric acid, potassium citrate and sodium citrate, rendering the word natural deceptive to consumers.

"By marketing its Crystal Light products as 'natural', Kraft deceives consumers and takes advantage of their preference for foods made entirely with natural ingredients," CSPI Litigation Director Stephen Gardner wrote in a Jan. 9 letter to Kraft Foods Group.

CSPI threatened to seek a permanent injunction barring Kraft from making its "natural" labeling claims unless the company changed its marketing practices.

Caroline Krajewski, a spokesperson for Kraft Foods Group, Inc., said Kraft's "labels comply with the law and are not misleading". She pointed out that a federal judge in California recently ruled Chrystal Light's claims comply with FDA regulations.

In the case before the Northern District of California, plaintiffs alleged Chrystal Light's products contain artificial ingredients, namely potassium citrate and sodium citrate, making them unqualified to bear a "natural flavors" label.

Ronald Whyte, U.S. District Court Judge, concluded the products did not contain additional artificial flavors that resemble the natural lemon flavor.

"While these substances may be artificial ingredients, nothing in the FDA regulations suggests that these ingredients are flavors, artificial or otherwise," Whyte wrote in a July 28, 2013 order granting in part and denying in part a request by Kraft and other defendants (Cadbury Adams USA LLC and Back to Nature Food Company) to dismiss a lawsuit.

"Since the Chrystal Light products refer specifically to the natural lemon flavor, rather than natural ingredients generally, the fact that the product contains some allegedly unnatural substances like potassium citrate and sodium citrate does not render the label false or misleading under FDA guidelines," Whyte concluded.

Kraft Foods is not the only food company that faces the prospect of a lawsuit over its labeling claims. On Jan. 9, CSPI also sent pre-litigation notices to Smart Balance, Inc., and Abbott Laboratories.

Smart Balance's claims, "help block cholesterol", on its "Blended Butter Sticks" are unlawful disease-prevention and health claims as well as false, misleading and deceptive, CSPI contends.

Boulder Brands, which owns Smart Balance, did not respond to a request for comment.

In a third letter, CSPI alleges that Abbott Laboratories' claims related to its "Ensure" nutrition and health shakes are deceptive and unlawful.  

Although Abbott markets the shakes as healthy beverages, drinking the recommended amount of two bottles daily would contain as much as "44 grams of sugar and 700 caloriesmore sugar than a can of Coke and more calories than four cans of Coke," the health advocacy group said.

Michelle Zendah, a spokesperson for Abbott Nutrition, said the company is aware of CSPI's letter.

"We stand behind the science and the claims supporting our Ensure brand," she said.