A number of readers have written to ask whether there's a electronic version of On Food & Cooking in the works, mainly to make it easier to find single terms or phrases quickly in those hundreds of thousands of words. Good question!
Yes, there is an ebook in development. Meantime, for the rest of us with hard copies, myself included, here's an interim solution. Go to the Google Books entry for the book (right), scroll down to the lower right corner of the page, and you'll find a search box. Type in a term and hit Search. It will give you snippets around the term, and page references. The entire text isn't viewable on Google Books, so you'll probably have to go back to your hard copy to see all the appearances of the term. And for some reason the search index isn't complete; it missed several entries for "capsaicin" in my test. But it's much more complete than the book's printed index.
I'm working with people at Google to place a permanent search box for the book right on this website. Stay tuned.
Google Books entry for On Food & Cooking: