How to tell if your jam is bad, rotten or spoiled?
The first sign of caution with most jams is when a liquid begins to form on the top of the product. It goes downhill quickly from there as the consistency becomes thicker and the colour becomes darker. Then it can develop an unpleasant odour, which is almost always followed by an unpleasant flavour and then mould. Once there is any mould at all present, the entire jar must be tossed. Mould spreads very quickly in a soft environment like jam or jelly, whether you can see it on the bottom of the jar or not. Mould spores that can cause serious illness can spread quickly and easily through the entire jar. It's a good idea to put a label on the product indicating the date it was opened, and, before consuming, to examine it carefully for evidence of deterioration, especially mould.
How to store the jam to extend its shelf life?
All preserved fruits should be stored in a cool dry environment not susceptible to temperature change. When items go through temperature changes of cool to warm and vice versa, the moisture in the air tends to condensate inside the packages. This moisture allows mould to grow and your jam to spoil. You should always make sure to use clean utensils when serving jams in order to avoid cross-contamination. Normally, there is no need to store jams in a fridge. They should be stored in a cool, dry, airy place.
How long is jam good for when prepared in a dish?
That depends. In general, jam lasts only as long as the quickest expiring ingredient it is mixed with.