We are doing an experiment where mice must eat a highly preferred food, which has been manipulated to have an unpleasant taste. We planned to use quinine but it may not arrive in time for our experiment.

Is there something else we can put on their food which will a) have no smell (so the mice will still be motivated to approach and try the food), but b) taste unpleasant to a mouse? Oh, and perhaps I should add, c) it should not kill the mice.

Thanks in advance for any ideas!