Many packaged foods contain sugar, which may be processed using bone char. I read on the net that the usage of bone char in sugar production is decreasing.
How can I identify whether the sugar in a packaged food is vegan or not?
This answer is partially specific to the United States.
There's a few indicators you can look for either in the ingredient list or on the package itself:
Here's a pretty in-depth source on the use of bone char, and contains some more information specific to the U.S.
There's talk here that Australian sugar manufacturers no longer use bone char to process their sugar. Have also read that local New Zealand sugar is also free of bone-char, but can't find a cited source at the moment.
Sugar produced in South Africa does not use bone char.
A few veg*n sites mention that some European countries have banned bone char use. However, it's important to note that it may only apply to manufacturers within the country and that sugar processed with bone char could be imported.
So, if the type of sugar isn't specified on the package and it isn't a local product of a country mentioned above, your next course of action would be to contact the food manufacturer directly and hope for a straightforward answer.