The larger number of entries are on basic foodstuffs and the plants and animals from which they are derived. Into this category also fall most of the forty "feature" articles, on topics such as "pig", "garlic", "sugar", and — the longest entry, at six pages! — "chocolate". Here is the historical discussion from the three pages on "coconut":
"The coconut is mentioned in Indian documents BC (see Achaya, 1994), but remained unknown in the western world for a long time.
No part of Asia west of India is suitable for it, and climate also barred it from China, although it was known in the south, and was taken north as an exotic delicacy. Marco Polo encountered coconuts in Java and Nicobar in the 13th century; and Vasco da Gama found the palms growing on an island off Mozambique in 1497/8. It seems likely that Arab traders had been responsible, much earlier, for introducing it to E. Africa.
As for the New World — whether or not the coconut had already existed on the west coast of Panama — what really mattered were the introductions of it by the Spanish (to Puerto Rico in the first instance) and by the Portuguese (to Brazil, in the 16th century). Cultivation soon spread to all suitable regions; and began in Florida much later, towards the end of the 19th century."
Also covered are prepared foods and dishes, cooking, culinary terms, and the study of food. There's an emphasis here on the English-speaking world, and to a lesser extent Europe, but there's solid coverage of the rest of the world, both generally and in the form of entries on specific countries. There are entries not just on China (two pages) and India (one and a half), but also on Indonesia (one page), Pakistan (half a page), and Albania (a column), to list just a few. The column on Iceland, for example, covers its lamb and dairy focus, the cultured milk preparation skyr (on which there is a separate entry), and techniques for preservation (and a controversy over dried cod's heads in the 1910s), finishing with a paragraph on Icelandic writings. ("Although little has been written in other languages about food in Iceland, there is an interesting literature in Icelandic.") Other entries include a half page on Anglo-Indian cooking and two pages on medieval cuisine.
The Companion has no recipes, nothing on wine (though there is an entry on grapes as food), and only a little on nutrition, metabolism, diet and other "food science" topics. Some of its entries are obscure, but they often provide background (the country entries, for example, open with brief paragraphs on geography and politics). The text is reasonably dense, with three columns to a page, but not so small as to make reading uncomfortable, and the entries are clearly laid out. The only illustrations are the occasional line drawing, used to good effect where something would otherwise be hard to visualise, such as the strange appearance of the cashew 'apple' and 'nut'.
Anyone with an interest in food that goes beyond recipes, cooking, and colour photographs should enjoy a good deal of The Oxford Companion to Food. And I can vouch that people without much of an interest in those things may also find it fascinating.