All apple seeds, regardless of how pristine the growing conditions, contain hydrocyanic acid (also known as cyanide or prussic acid). One would have to ingest close to a cup of pure apple seeds to iduce death. THe leaves and pits of various plants of the prunis family, such as cherries, apricots, and bitter almonds, also contain prussic acid and can be lethal. There are many valid sources where one could look to find information on cyanide-containing plants. Kingsbury's "Poisonous Plants of the United States and Canada" is one. Lewis' "Medical Botany" is another.
These sources are far more reliable than New Zealand farmer-Pushikin's statements, made in his gramatically embarrassing message preceeding my reply-"let me tell you!!!"