You can get Worlds Best from a few places - it is very pricey though, which is why I have never bothered with it, am afraid I would rather spend the money on better quality food for them.
Milly's mum - I hate the smell of the pink stuff too, but am having to put up with it till the bag is finished, which will be ages as I only have one foster in at the mo, and she doesn't seem to go that much!! My neighbour uses it cos she thinks it works well at odour control - she doesn't realise that if she scooped her tray rather than just emptied it completely every other day (1 tray for 2 cats, but they do have outdoor access and also access to the neighbours house and his tray), then that might do a better job of odour control!!