i once worked in a restaurant as a commis chef. i hadn't got a clue what that meant (and still don't) but it did involve having to go on a council run kitchen hygiene course. so i'm qualified hygenic.

anyway, one of the important things i learnt was to always check your milk bottles for dead mice. another important thing was never to eat the raisins you find in the store room cupboard.

i also learnt that you need different coloured chopping boards for different types of food - cooked meats, uncooked meats, salads, mannequins, spleens etc.

perhaps these bags use a similar coding. perhaps not. but it's a nice story anyway.