Heat oil on medium heat in an extra-deep 12-inch nonstick skillet. Peel and coarsely chop the onions, adding them to the skillet as you chop. Seed and coarsely chop the peppers, adding them to the skillet as you chop. Add garlic; raise heat to high. Crumble beef into skillet; cook, stirring constantly, until no longer pink, about 6 to 7 minutes. Remove from heat; stir in Worcestershire. Drain into a colander. Let cool slightly, then divide into 3 portions, each about 3 1/2 cups. Store in freezer-weight, zipper-top plastic bags; freeze until ready to use.