We make jam in varying quantities every year. Dad gave me back one he found in the cupboard, saying he wont eat it, dated 2014. Unopened, we're pretty thorough about cleaning and sealing jars. I haven't opened yet, but should I eat or not? It appears ok from the outside looking in. I tend to be in the looks ok, smells ok, tastes ok, probably ok, camp, but is there anything else I should consider?