Preheat oven to 350°F. Grease and flour a 9 x 5 x 3-inch loaf pan. Combine flour, sugar, baking powder, baking soda and salt in a medium bowl; set aside.
Blend peanut butter and corn syrup in a large bowl until smooth. Beat in egg. Alternately add flour mixture and milk, stirring just until moistened. Fold in chocolate chips, if desired. Pour into prepared pan.
Bake for 60 to 75 minutes or until toothpick inserted in center comes out clean. Cool in pan 10 minutes. Remove from pan; cool on wire rack.