The blue forms are the forms currently being used - the white ones have been phased out.

With regards to food items you take in with you, definately no meat, fruit or dairy. Any thing else is generally ok but all items must be declared from babyfood to candy. Formula milk is ok if it is already made up in a bottle or in a sealed carton. Any leftover fruit on the aircraft is best given to the cabin crew to put in the trash - even the fruit leftover from business class has to be collected together and not left lying around on board. If in doubt just declare an item - mostly you'll be waved through, but sometimes they do random checks and for agriculture purposes x-ray your bags again. They won't be happy if they find something you haven't declared! At Tampa last year, one of the sniffer dogs actually sniffed a jar of unopened Bovril in someones bag, all that happened on that occasion was it got taken away from the passenger.

You can't take in flowers or plants either in case there are any insects on them!

Something else to be aware of is that if you are a family travelling with different surnames then you'll need more than one form as it's one form per family but only with the same name!

The cabin crew are fully trained to answer any questions you may have with the customs and immigration forms. Most airlines also have a card in the seatback pocket on how to complete them and show a video. I know BA do.

Hope this helps.