Part of the show Climate Change & Alternative Energy
House breakers seem to have more than just an appetite for crime - frequently they get tempted by more than just the contents of the jewelry box and tend to rifle through the fridge too, leaving the discarded remnants of their snack at the scene. Unfortunately for them, the remains of their last meal could be their undoing because minute traces of saliva left in the food often contains DNA which can be used to identify the culprit. A number of food-felons have been convicted in this way over the last 10 years or so, but exactly what foods produce the most reliable for DNA fingerprinting wasn't known. So US researcher Heather Zarsky held a dinner party for 13 colleagues and invited them to snack on a range of offerings including fruit, corn on the cob, pizza, chocolate and vegetables, and to leave behind the discarded remnants of their meals. She then analysed the leftovers and managed to produce complete DNA profiles of nearly half of her 'guests', and partial profiles from a further third. The most successful burglar-busting foods turned out to be cheese, carrots, apples and pizza, but would-be housebreakers would be advised to stick to chocolate, because it proved almost useless for DNA techniques, possibly due to the small size of the pieces left behind.