Yeast is not an ingredient of a McDonalds ice cream cone.
Ice Cream Cone Ingredients:
water
enriched flour (wheat flour, niacin, reduced iron, thiamin mononitrate, riboflavin, folic acid)
tapioca starch
corn starch
sugar
partially hydrogenated soybean oil and/or cottonseed oil
leavening (baking soda, ammonium bicarbonate)
salt
annatto (color)
natural (plant source) and artificial flavor
caramel color
corn syrup
soy lecithin
See McDonald's USA Ingredients Listing for Popular Menu Items to find out which product contains yeast.
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