Sales of products certified free of genetically modified ingredients are up 21% over last summer, according to information provider SPINS, citing data from the more than 900 independent and regional chain stores making up the natural food channel.

The growth is shared by related categories: Organic (up 17%), Fair Trade USA-certified (19%) and gluten-free labeled or certified (22%), and is further buoyed by the overall strength of natural food retailers.

The channel has consistently reported double-digit dollar growth rates averaging 15% since the start of the year, noted the firm. Specialty/gourmet products that share a natural label are also enjoying success.