Re: What is the history of the food battery?

By food battery, I am presuming that you mean a battery made using a 
copper penny, an anodized zinc nail, and a lemon - or the equivalent 
thereof. These are the most common ingredients for making the battery but 
having a copper strip or a zinc electrode makes things a little easier. 
(The bigger the electrodes, the more current you can generate.)

If that is the case, then the first records of such a battery date back 
to around 1850. It is hard to say for certain because it would appear 
that several people were making such batteries and demonstrating them to 
their associates long before anyone wrote the process down. However, the 
August 7th, 1852, of Scientific American makes reference to a 
demonstration of a lemon juice battery (or "Voltaic Lemon" as it was 
called in those days) based on the work of Dr. Chevalier LeMolt, a 
surgeon. He is likely the one that should be credited with its discovery.

He did include a description in an article that appeared in 1853, in the 
Lancet - a medical journal. In it, he explicitly says that he has given 
the battery the name "VOLTAIC LEMON" and describes the workings of the 
battery - "... it contains in itself the elements of the pile, the 
exciting acid solution, and the porous membrane formed by the internal 
skin of the fruit." In other words, it wasn't just something that he 
happened to notice but something to which he had given a considerable 
amount of thought, particularly as to how the battery worked and how it 
was similar to other batteries that we being invented at the time.

Since the principle is fairly simple, being one of having two metallic 
strips in contact with an acidic solution and connected to an external 
circuit, pretty much any acidic fruit juice will do the trick. There are 
lots of variations on the lemon battery using grapefruits, oranges, and 
even potatoes that have been invented since then. But as far as I can 
tell, the VOLTAIC LEMON was the first.

Hope this answers your question.