Oh, don't worry about eating them, they won't hurt anyone. (I'd hate to think of such luscious tomatoes going to waste!)

Hard white areas can form in tomatoes as a result of environmental factors, but it's hard to say exactly what does it. Variety plays a role; so does plant stress from water or heat, or individual plant variation in non-hybrids. It often clears up as the season progresses, though some plants will keep doing it to one degree or another. If the white spots bother you, cut them out, but I don't. It's not connected to any disease in particular.

Severe stresses cause what's known as "grey wall", where half the fruit becomes hard and whitish, but these fruits look fine and juicy. Enjoy, by all means!

--Alison