Food Unwrapped

Kate Quilton investigates the potentially dangerous levels of mercury in tuna

Another selection of favourite investigations, with Jimmy Doherty heading to South Africa on the trail of sweet piquante peppers and visits the company that has exclusive rights to grow, process and market these colourful chillies. Kate Quilton is in Hawaii to investigate the potentially dangerous levels of mercury in tuna, and Matt Tebbutt finds out why the bags of ice cubes in supermarkets are so crystal clear