Mix milk, vinegar and mustard and let set for 15 minutes. This will make a mustardy, buttermilky dressing to coat the fish.
In a separate bowl mix cornmeal with all the seasonings.
Dip fish fillets in the milk mixture and then in the cornbread mixture.
Spray broiling pan with cooking spray or brush with a little olive oil.
Place fillets on prepared pan and place pan under broiler 4 inches from heat.
Broil for 4 minutes per side or until fish flakes easily with a fork.
Serve with lemon wedges if desired.