What it is
E415 is xanthan gum, a polysaccharide produced by fermenting plant sugars (usually from corn, soy, or wheat) with the bacterium Xanthomonas campestris.
Why it matters
The go-to thickener in gluten-free baking, salad dressings, sauces, ice creams, plant milks, and a thousand convenience foods.
What to do
Always vegan.