Greetings, Katherine! First, I'd say that any organic material that can be avoided in historic houses is better than trying (and, usually failing) to repserve with a coating. As you seem to have discovered, there are many "museum-source" retailers that will sell you replica food, but at a high cost. You can prowl dollar stores and similar retailers and find reasonably good facsimiles of fruit and vegetables. Where you might have to spend more, would be joints of meat and that sort of thing. But again, it will be a one-time expense, and in my opinion, well worth it. Vivian