CCC 1377
Christian Mystery›SECTION TWO THE SEVEN SACRAMENTS OF THE CHURCH›CHAPTER ONE THE SACRAMENTS OF CHRISTIAN INITIATION›V. The Sacramental Sacrifice Thanksgiving, Memorial, Presence
The Eucharistic presence of Christ begins at the moment of the consecration and endures as long as the Eucharistic species subsist. Christ is present whole and entire in each of the species and whole and entire in each of their parts, in such a way that the breaking of the bread does not divide Christ.