Chemicals in food can include naturally occuring toxins as well as agricultural chemicals such as pesticides and herbicides. Food Standards Australia New Zealand mandates food standards that set very low, safe limits for these chemicals in the food we eat that take into account people who eat a lot of a specific food as well as small children. They also survey food as it is eaten (eg cooked potatoes and apples without a core) and regularly find that chemical residues are well below safe standards and in many cases, cannot even be detected. You can find out more about Food Standards Australia New Zealand’s maximum residue limits here