Here is a wonderful and extraordinary account of the most recent Eucharistic miracle (1996) which happened in our present pope's former archdiocese while he was Archbishop. It is the story of the discarded host which was discovered by a parishioner who informed the priest. Properly the priest retrieved the host but, as he could not consume it, placed it in a cup of water in the tabernacle (this is a licit and proper thing to do with an unconsumable host). Yet the host changed miraculously! Here is the story which includes how it was blind tested by a science lab, who tested a sample and found it to be heart tissue...!
http://www.loamagazine.org/nr/the_main_topic/eucharistic_miracle_in_buenos.html
or
http://absoluteprimacyofchrist.org/pope-francis-eucharistic-miracle-in-buenos-aires-argentina/
