can i get dry socket?

I had my 4 wisdom teeth pulled out 2 days ago. None of these teeth were impacted. I noticed today while looking at the bottom two wholes that there was some white substance in the blood clot that has formed in both holes. Could this possibly be food? Should i be worried about this? Or could i possibly have dry socket? And also is it less likely for me to have dry socket because all my teeth were ruptured at time of surgery? Please get back to me! Thanks a lot!