Don't worry yourselves, we have a great food source coming soon. Soylent green will settle all food problems.
Beer and whine may not all be vegan. Many manufacturers, brewers and vineyards use various non-vegan filtering agents.
That's strange. Did she have a reason to think that you were serving her a "vegan" sandwich, or maybe she had asked for one? Otherwise, I don't understand why she'd answer your question like that.
Isinglass made from fish bladders is used a lot in many beers for conditioning and removing the yeast.