Even if you're a diligent home cook it's hard to avoid this chemical as it's used to preserve dried fruits ... a key ingredient of all those above mentioned goodies. This months chemical to avoid is Sulphur Dioxide (Sulfer Dioxide in the U.S.).
Sulphur Dioxide is a preservative used to stop moulds growing on dried fruits like raisins, sultanas, apricots and even coconut. It's also found in meat products like deli meats, sausages and minced meat.
Sulphur Dioxide is a sulphite, which means it can cause some severe reactions in people that are susceptible to sulphites (sulfites), these mainly being asthmatics. In an asthmatic it may cause severe breathing problems, severe allergic reactions and even death!
Dried fruits like raisins and prunes are among the highest sulphite carrying foods, so if you are an asthmatic and indulging in your annual Christmas treat make sure you have your inhaler handy should any wheezing start.
You'll note that in my cookbook the use of dried fruit and dried coconut is not recommended as cake or cookie flavourings and this is why. As an alternative choose organic dried fruits or fresh fruit. The organic fruits won't last as long as they don't have the preservative, but you can freeze them.
For more information about Sulphites please read last months blog post "Suffering Sulphites".
P.S. Don't forget also those glace cherries are choc-loaded full of red food coloring - they aren't naturally that way!!