This sentence is a bit of a puzzle. There doesn’t appear to be a subject. cibos, “food”, would be a good subject–it’s a plural and fits well with the passive plural verb, consumuntur, i.e. “the food is eaten”. cibos, however is accusative, and therefore the object of a verb, not the subject. It should be cibi (and appositos would likewise be appositi). I’m not sure how else to read the sentence. Either the artist used poor Latin, or made use of a rule of Latin grammar that is unknown to me. The translation I’m going to go with is
The food placed before Bel is consumed by the priests, their wives, and their children during the night.
I stuck some possessive adjectives for the wives and children. The Latin doesn’t do this, but it sounds weird in English if your don’t.