I don't know if this helps at all, there are one or two tiny blood spots in the yolk, no biggie, but I've never come across a meat spot... What do they look like?
When the sac in the ovary ruptures to release a yolk, sometimes a capillary gets busted in the process and a drop or 2 of blood ends up in the egg. Not sure about the "meat spots" but it's probably something similar. I've seen one, it was just a little booger with blood on it. I picked that one out. Either way, it's harmless.