They love corn meal in moderation so that it does not heat up or sour the bed. I put a 5 lb bag of flour in one of my BIG beds and it went away pretty quick.

You could always test some in a small test bin and see how a small population of worms reacts to it. If they survive, you could start using it in moderation for the large population and so long as everything stays healty, you could increase the use.

Remember that whatever goes into the worms comes out in the compost. Salt isn't good for the worms, and it isn't good for the garden either.