I did now about grapes/raisons but here is a few other foods that are poisonous to dogs are:
walnuts and macademia nuts
raw liver
Tea, coffee and cola type drinks (same poison as chocolate)
grapes raisins and sultanas
pear pips, apple pips, kernels of plums, peaches etc
turkey skin
raw fish especially salmon
some mushrooms
cat food can cause metabolic imbalances
milk and other diary products - dogs are lactose intolerant
raw eggs
potato, rhubarb and tomato leaves/stems
yeast dough
citrus oil
vitamin supplements containing iron.