Almonds
In 2014, Whole Foods had to recall some of its bitter almonds, which contain traces of hydrocyanic acid as well as glycoside amygdalin, which, when heated or exposed to certain other conditions or chemicals (like the kinds in your digestive system), will be converted to hydrogen cyanide.[3] That’s right: amygdalin again, just like with the apricot seeds. Both raw almonds and apricot seeds are marketed health products, but both can be deadly when ingested.
Cyanide compounds are actually pretty ubiquitous and plentiful in nature; in fact, if you walked out into nature and just began eating food, many of the things you ate raw could kill you, as is, without human intervention.
This information is available, along with another group of possibly poisonous foods at Listverse. Just follow the link to see the list.
Coffee out on the patio this morning!