I thought of something else that will help with the bleeding from the anal area. First, before and after a BM, rub some Vaseline around the area, also, take a stool softener daily, this will help you not have to strain so much. For the hemorrhoids, try this, first, apply some preparation "H" to the hemorrhoids, then, on top of that, apply some triple antibiotic ointment, this will help keep the area both moist, the fissures not so dry and help the hemorrhoids as well.
The foods you mention will not normally cause your stool to change color, foods like Beets will however. If anything is causing the blood, I would say it was the fissures and small cuts, also, a hemorrhoid will cause bleeding if you strain too hard.
I don't feel you have anything to worry about, but, if it continues to scare you or gets worse, then call your doctor and they will do a stool test to determine if it is the kind of blood to worry about.
Oh yes, the strong pinch would not cause this type of bleeding.