Trust your nose and your tongue. Smell it, taste it; if it smells and tastes fine, then it’s probably fine. (Strawberries are rather acidic and jam often includes lemon/lime juice, so the odds that it’s something harmful are rather small.)
That said if I had to take a guess: you didn’t skim off the foam while you were cooking the jam, and that foam jelled itself. If that’s correct it’s safe to eat.
I make jam several times a year and I never had this kind of deposit. I would throw the jam, I’m too young to die from food poisoning (like botulism, if there’s not enough sugar).
Sometimes when jelly or jams go bad there is a white mold that can grow pretty quickly if the seal on the jar was imperfect, jars used were not sterilized, or if there was too little sugar used in process. If that is in fact mold, you need to toss it.
How much sugar did you add? The preservative here is sugar, and the mechanism of preservation is reducing the water activity so much that nothing else can grow. The resulting sugar jelly should be much denser than the fruit.
If you fruit sinks, the specific gravity of the jam might not be high enough.
Add comment