Yoghurt group Chobani has been censured for a US advert that compared the ingredients used in its products with rival lines.

The National Advertising Division of the Council of Better Business Bureaus - the advertising industry's self-regulatory body - questioned Chobani's spot following a challenge from Yoplait owner General Mills.

Chobani has led the boom in Greek yoghurt in the US but competition is intensifying, with General Mills and Danone putting pressure on the privately-owned company.

The ad, entitled 'Farmland', set up two farm settings – a synthetic farm where so-called "other 100-calorie yoghurts" were made from the contents of test tubes and plastic cows were filled with powered chemicals and a real farm with boxes of fresh fruit and live cows.

On Chobani's Facebook page, the company posted still photos from the commercial and side-by-side photographs comparing the supposed ingredients of "others" versus "ours".

General Mills noted Yoplait Greek 100 was the best-selling 100-calorie Greek yoghurt on the market and argued the ad "communicated that Yoplait Greek 100 yogurts contain no real fruit and are made with artificial flavours and colours instead of fruit", the NAD said.

Chobani insisted its claims were "substantiated against some or most competitors, including Yoplait Greek 100 but argued "reasonable consumers would not perceive its commercial as referring specifically or exclusively to Yoplait Greek 100", the body added. The company also described the spot as "deliberately playful and unrealistic".

However, the NAD judged the commercial conveyed a broad, comparative message that competing Greek yogurts – whether construed as 100-calorie Greek yoghurts, or more broadly – are made with artificial colouring, artificial fruit flavouring, and possibly artificial milk.

Yoplait Greek 100 is not made with artificial flavours, colours or milk, the NAD said.

"NAD has long held that claims that expressly or implicitly disparage a competing product must be truthful, accurate, and narrowly drawn. Consequently, NAD recommended that the advertiser discontinue the commercial," it added.

NAD recommended Chobani changed its Facebook advertising so it no longer suggests that most competing 100-calorie products use aspartame. However, it said Chobani could promote its use of natural sweeteners, compared with the artificial sweeteners used by Yoplait and other brands.

In a statement to just-food, Chobani said: "While Chobani disagrees with some of the NAD's conclusions, it appreciated the opportunity to participate in the self-regulatory process and respects the decisions of the NAD. Our Farmland ad had playful and dramatic imagery to convey how Chobani uses only natural ingredients to make its products. The ad ran its scheduled course and we're now focused on the development of future marketing efforts."