People ask me all the time if pottery is food safe. Most potters are very sensitive to making sure that they do not use lead-based glazes, such as the ones you find on brightly coloured pottery from such places as Mexico. There was a time when the only way to get great color in glazes and slips was by using toxic elements such as lead and barium.
But today, most potters, including myself, purchase safe stains and colourants.
Often, these are applied underneath a hard, high fired glaze to doubly ensure your safety. On the rare occasion when toxic materials are used, they are usually applied on the exteriors of decorative pieces where they will not have contact with food. It is best not to use earthenware pottery for cooking, since this porous clay is low fired and often oils and vinegar leach into the clay causing discolouration and possible contamination.
All pottery created in my studio is totally safe for food, cooking, dishwashers and microwaves.