"How long do they last? I have a couple of slices that are over four years old that look just like new."
Wow, preservatives are scary. First slice pictured below is a homage to Vincent Van Gogh's Starry Night:
"If you've read Umberto Eco's book, 'Travels in Hyperreality,' you will understand this piece. If you haven't, all you need is a sense of humor to appreciate a slice of iconic fluffy white American bread and the concept of a homespun, handsewn sampler paired with one of the most easily recognized Impressionist art works in the world."