The trend for brightly coloured food has reached savoury snacks, with the arrival of New Monster Munch Pickled Onion ­ which turns tongues blue. The new flavour, which was launched in the United States last year, contains dye which turns blue when it comes into contact with moisture. It will be on shelves here from August 13 for 16 weeks and comes only in a 25g packet to make the most of school lunchboxes. Original Pickled Onion flavour will still be available. {{MARKETING - P&P }}