Australian consumers view Cadbury as the country's "most authentic" food brand, research compiled in the Authentic Brand Index found.

The survey of consumer attitudes, conducted by Principals and Synovate, found that other "authentic" food brands included Vegemite, McDonald's, Coca-Cola, Kellogg's and Nestlé.

According to the researchers at Principals and Synovate, Australian consumers value brands that have a distinctive story, original edge and deliver what they promise.

"There is real evidence this year that consumers are holding brands more to account and are increasingly critical in their assessment of their authentic credentials. Overall, consumers were less likely to rate brands as authentic in 2008 than previously," Principals planning director Wayde Bull said.

"It's unlikely to get easier for brands in future, given the further growth of social media and the abundance of unfiltered third-party information available to the consumer."