How Google reads your menu
Search engines read text. A menu saved as a photo or a PDF scan can't be read line by line; a menu written into the page can. There is also a shared format for describing a restaurant, its menu sections, dishes and prices, published at schema.org [1][2].
A friend of ours, Marco, kept his family pizza place's menu online as a PDF of the printed one. A regular told him she'd ordered from the chain down the road one night: the PDF wouldn't open on her phone, and his line was busy. A menu written into the page opens on any phone, and is quick to update when prices change.
Every site we build writes your menu in that format, from the same text you see on the page, so what a search engine reads matches what a diner reads. We can't promise it shows up anywhere: that is Google's choice.
Sources
[1] schema.org/Restaurant. [2] schema.org/Menu.