As far as I have read, the best kind of flax seed oil is the kind that *comes refrigerated*, where the manufacturer specifies that it needs to stay in your refrigerator. Be wary of the flax seed oil sitting out in the store, outside of the refrigerated section.
I highly recommend Barlean's flax seed oil, which must be kept cold. I used it in the Budwig protocol for our dear dog when she had cancer, and it worked wonderfully; the vet called it 'miraculous'. We were not able to completely eradicate the cancer, but we put it on pause for over a year and our dog had one of the healthiest years of her life before she passed, at age 15.
Trusted and old non-profit organizations can change for the worse, unfortunately. Or maybe this oil is perfectly fine! I am just speaking from what I have heard/read/tried for myself.