Milk.
Not all cats like milk. Real, solid food would be a lot more appealing to a stray that never gets a proper meal. Cats love turkey -- just plain packaged deli slices are fine -- and canned tuna. Also, most cats love Innova Evo dry food. They look like little brown cat cookies, and most cats just adore it. Try luring it with the meat, and if it doesn't come, leave it and a plate of the dry food. If you keep feeding it, eventually it'll come to you. And if you catch it, you're going to need to feed it, so you might as well buy the food now; they have it at Petco, I think. Otherwise, the dry food called Taste of the Wild is almost the same.