Passata is a liquid tomato puree that has been strained of seeds and skins. It provides a fresher taste and more vibrant colour to your bolognese sauce compared to conventional ready made pasta sauce, tomato puree and tomato sauce. Passata is now commercially available in most major supermarkets. If you cannot find it, replace with plain canned tomatoes of equal weight and blend it till smooth before using. I also prefer to mince meat at home with a meat grinder or food processor. That way you are sure of what your children are getting to eat.