Could this word be Whortleberries?

It has 14 letters.
Its fruits taste wonderful and rich like blueberries but with a deeper, richer flavour.
It can be made into jams, syrups or juice.

Is it safe to use for a very long time?
Whortleberries have a lot of health benefits. They have a high antioxidant content that is beneficial to health like every other berry fruit.