What's the difference between ‘use by’ and ‘best before’?

In the UK we throw away 6.7 million tonnes of food every year - roughly a third of everything we buy according to figures from WRAP, the government’s waste watchdog. At the same time the number of cases of listeria, the most dangerous form of food poisoning, in people over 60, has doubled in the past nine years. In both cases the culprit is confusion over food labelling. So what’s being done to help us understand what food is safe to keep and eat, and what isn't. Jenni is joined by campaign manager Julia Falcon of the Love Food Hate Waste campaign from WRAP (Waste and Resources Action Programme) and by Dr Barbara Lund, food microbiologist from the Institute of Food Research.

http://www.bbc.co.uk/radio4/womanshour/02/2009_25_wed.shtml