In a food processor, cover and process the vegetables in batches until finely chopped. Drain vegetables and discard liquid.
In a stockpot, bring vinegar, sugar, water, salt, mustard seed and celery seed to a boil. Add vegetables; return to a boil. Reduce heat; simmer, uncovered, 1 hour or until thickened. Store in airtight containers in the refrigerator up to 1 week. Serve with sausage or other meat.