Raw bread dough - when dogs ingest raw yeast dough their stomachs act as an instant oven creating carbon dioxide that will expand their tummy. (poochhotel.com)
Grapes and raisins, onions and garlic (Allium sp.), avocados, macadamia nuts, alcohol, raw yeast bread dough and xylitol are all different types of foods that can be dangerous for pets. (aspca.org)
Below freezing, the yeast may be dormant and may actually die (which is why you don't want to freeze raw yeasted dough). (glutenfreeonashoestring.com)