Speaking of shelf life...
http://www.freerepublic.com/focus/f-chat/2603220/posts History of canned foods
http://en.wikipedia.org/wiki/Arabia_(steamboat) Wikipedia article, which also mentions the still edible canned foods found aboard. She sank in 1856, 9 years previous to the sinking of the Bertrand. She was discovered 20 years later than the Bertrand, making her canned goods both earlier as far as processing; and older in terms of span between canning and discovery & testing...and tasting.
It was probably still good because of no expiration dates, so it didn’t know it was “supposed to” go bad.
I say that as a culinary professional.
/johnny