In linguistics, collocation is a sequence of terms or words that co-occur often enough to deem that it does not simply happen by chance.  In more layman's terms, collocations are typically common adjective-noun or adverb-adjective pairs that are used so often, they are now commonly accepted as the "correct way" of saying something.

Some food examples are:

• Strong (or weak) coffee.  While it might work to say "watery-coffee" or "thick-coffee" the collocation is strong or weak.
• Fast food.  Americans would never say "quick food."
• Eating for here or to go.  I would consider this an America collocation.  In England they say "take-away" when eating "to-go."
• This sauce is soupy.  When describing a sauce that is too watery (or should be thicker), "soupy" is most often used, but of course we'd never describe watery paint, for example, as soupy.
• Melt in your mouth delicious/good. This might be more of an idiom but melt-in-your-mouth is used to describe decadent or savory things to eat, particularly if chocolate is a key ingredient.