process for preparing baked dog biscuits having a coating containing at least one inorganic pyrophosphate , comprising : subjecting unbaked dog biscuit dough to a liquefied coating material containing at least one inorganic pyrophosphate , thereby , forming a coating of such liquefied coating material on the dog biscuit ; and baking the unbaked dog biscuit dough pieces having a coating containing said at least one inorganic pyrophosphate . the baked , coated dog biscuits are chewed and / or eaten by dogs , with the result that tartar accumulation on their teeth is reduced or prevented .