How do you prevent mold in tomato based barbecue sauce?

To prevent mold in tomato-based barbecue sauce, ensure proper acidity by using enough vinegar or lemon juice, which inhibits mold growth. Store the sauce in clean, airtight containers and refrigerate it promptly after use. Additionally, always use clean utensils when serving or handling the sauce to avoid introducing contaminants. For long-term storage, consider canning the sauce using proper methods to create a sealed environment.