The Old Mill Set contains script that won't allow you to eat toast unless you have the Bakery Set installed in addition to the Old Mill Set.  The script is as follows:

if (DownloadContent.GetPackageName(new PackageId(0xac242b0c52bfd895L, 0x2dae587d2fbb4286L)) != null)
{
base.AddInteraction(HaveJamAndToast.Singleton);
base.AddInventoryInteraction(HaveJamAndToast.Singleton);

The package ID referenced in the script is for the Bakery Set.

Hope this helps someone.