I can't help but think that there has to be a simpler solution.
With other expensive pieces of machinery, there are usually big signs warning against eating/drinking in areas where spillage would be inadvisable.
Yet here you have a $100m+ piece of equipment (potentially with hundreds of passengers also on board) that they accept that the 2 key personnel could well slosh liquid all over the critical electrical controls....
I know that pilots have to eat/drink, but they also (generally) have to leave their seat to visit the toilet, leaving one pilot flying (and presumably during a quiet part of the flight).
From a flight operational perspective, what would be the downside of banning pilots from eating/drinking while seated at the controls?