I checked out info about this from the net, and it seems that "Cherry seeds, peach and plum pits, corn, chickpeas, cashews, and some other fruits and vegetables contain cyanogenic (i.e., cyanide-forming) glycosides (such as amygdalin) that release hydrogen cyanide when chewed or digested. As a result, some cyanide can also be found in fruit jams that contain these pit and pip extracts, such as quince. However, since the concentration of cyanide in these compounds is small, accidental cyanide poisoning from a food source is rare. But, if the correct materials are deliberately concentrated it can make an effective poison, as the Romans and Egyptians knew. They used to grind up peach kernels to make poisons."  http://www.ch.ic.ac.uk/rzepa/mim/environmental/html/hcn_text.htm

You could check some other sources as well. 

I read a brief newspaper article a few years ago reporting that a man in the USA had been recorded by a cororner as having died "by misadventure" as a result of cyanide poisoning after eating hundreds (or maybe it was thousands) apple pips in a single sitting.

Apparently he really liked the taste of the apple seeds so he started saving them, and planning to eat them all one day as a treat, not knowing that in such a quantity (whatever the number of seeds actually was!?) that the concentration of cyanide may kill him. He may not have even known that they contained cyanide.