Can you eat red tomatoes' seeds that turned black?

I bought bright red tomatoes from a supermarket that looked fresh, ripe, edible on the outside. I descry no evidence of Blossom End Rot; the tomatoes isn't blemished like pics below.

When I cut open the tomato, the flesh remains red and feels normal and fresh. But most seeds are black, rather than Goldenrod Yellow.

1. Why did these seeds turn black?

2. What, if anything, can be safely eaten? Just the flesh? Or even the seeds?

I forgot to photo-graph, but please edit this if anyone finds a picture of this snag.