While unsulphered dried fruit doesn't look as appetizing as the chemically treated fruit, consider this; Sulfur Dioxide is a gas that's created by burning oil or coal and smells like rotten eggs. It is also an air pollutant that can cause severe health problems in humans. That is far less appetizing than naturally sun dried fruit that has lost it's color.
Many dried fruit brands using Sulpher Dioxide also contain added sugar, which seems really unnecessary considering how sweet fruit is on it's own. Additionally, Sulpher Dioxide is used in products as a bleaching agent or disinfectant. How this chemical can then also be used as a food preservative is really beyond me, and sadly, it is in so many foods, including your favorite glass of wine. While it is unavoidable in some instances, like wine, I feel we should steer clear of this preservative wherever possible, especially for children.
Some people actually have a sensitivity to it and can have serious health issues as a result. If you are sensitive to Sulpher Dioxide, being exposed to it can lead to breathing problems such as asthma, chronic bronchitis and respiratory disease. Eating foods treated with Sulpher Dioxide when you have a sensitivity may cause an upset stomach, an asthma attack or a skin rash.
The FDA considers Sulpher Dioxide safe in small doses, but it doesn't sound very safe to me, especially in food for children. I recommend buying organic, unsulphered dried fruits whenever possible. They are available at most natural food stores like Whole Foods and Fairway Farms.