h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

This is a cool and thorough entry.
I have occasionally heard of something called a 'blue plum'. Is this a sloe?
Red onions, like red cabbage will turn a disturbing blue-green colour given the right incentive. My mother makes corned beef pie with red onions, and while the onions are indeed red when the pie is fresh, pie eaten for lunch the next day will contain odd blue things. I presume this is the same chemical?
Again, a very groovy entry.

There are actually a great deal of chemical indicators - all of them organic - which will change colour when exposed to an acid or alkali. They're much more common than you would think and, of course, they don't all work on the blue-red axis.

B

recently i got some red and blue plates the same food appears to look different on each one

But which does it look _better_ on?

B