From the Heinz product FAQ:
Where can I find out what ingredients are in my favorite Heinz products?
A full list of ingredients is included in the ingredient statement on the product label. "Natural flavoring" refers to herbs and spices that are derived solely from plant sources.
Does Heinz ketchup contain animal products?
Heinz Ketchup has never contained any animal products.
In addition, the FDA has set a standard of identity for ketchup that does not permit the use of any animal products. Any deviation from this standard of identity would mean that the product could no longer be called ketchup nor sold legally under the name ketchup.