Preheat oven to 400 degrees F (200 degrees C). Line a baking sheet with aluminum foil.
In a bowl, mix together the onion, celery, tomato paste, sloppy joe mix, bread crumbs, and egg. Work in the ground beef lightly with your fingers until thoroughly combined. Shape the mixture into a loaf shape, and place on the prepared baking sheet.
Lay bacon strips across the loaf crosswise, overlapping if necessary.
Bake in the preheated oven for 30 minutes, then decrease temperature to 350 degrees F (175 degrees C).
Bake until the meat loaf is no longer pink inside and the juices run clear, about 30 more minutes. Use a bulb baster to remove accumulating grease several times during baking. Allow to stand for 10 minutes before slicing.
