Writing up a prac report and need to know the typical concentration of a particular substance in a specific food type? The USA Dept of Agriculture has a very comprehensive database of more than 7,000 foods and 150 food components. Access it here.
The majority of MSDSs are hidden behind commercial logins. An American laboratory supply company, Sciencelab, has been kind enough to make its collection of more than 4000 MSDSs (basically any common substance) available for free here.
Both these resources can be found on the Useful Links page (from the Other Stuff menu)