Great question! (Especially when you consider that the plate and the food were made from the same materials. Edible plates?)
Maybe the crew blasted them out of the airlock the same way Ripley did with the Queen in Aliens?
Maybe they used the transporter to beam them down to a nearby planet?
Or, maybe that's really why Guinan was hired on TNG.
There are too many possibilities! What have you done to me! 😵