Reference sources (encyclopedias, handbooks, dictionaries, etc.) are important because they can help introduce you to your topic. These sources typically will give you an overview or background information that will include basic facts and definitions. The reference databases listed here also include more specialized, subject-specific works that are useful for giving you more in-depth overviews to various topics. All reference sources are helpful in that they give you a place to find more keywords or phrases that you can use to search article databases, the library catalog, etc.
These featured books are great places to get topic ideas and start your research.
The Oxford Companion to Food by 
The Atlas of Food by 
Encyclopedia of Food and Culture by 
Encyclopedia of Agriculture and Food Systems by