Analyticae Quaestiones & Responsiones de pane vitae

In his 25th Tractate on John, among other things, he says:
"This is the work of God, that you believe in him whom He has sent."
This, says Augustine, is therefore to eat the food which does not perish, but which remains into eternal life. Why do you prepare your teeth and your stomach? Believe, and you have eaten. In Tractate 26: To believe in Him, this is to eat the living bread. He who believes in Him, eats: he is fed invisibly, because he is also reborn invisibly.

IV. Concerning those who eat carnally, and those who eat spiritually, in the same Tractate, he says: Moses ate manna, Aaron ate manna, and Phinehas ate manna; many ate there who pleased the Lord, and they did not die. Why? Because they understood the visible food spiritually, they ate it spiritually, they tasted it spiritually, so that they might be spiritually satisfied. For we also today have received visible food: but the SACRAMENTUM sacrament is one thing, the VIRTVS SACRAMENTI power/virtue of the sacrament is another. How many receive from the altar and die: whence the Apostle says: He eats and drinks judgment to himself. Was the Lord's morsel not poison for Judas? And yet he received it, and when he received it, the enemy entered into him; not because he received something evil, but because, being evil, he received the good in an evil way. See, therefore, brothers, eat the heavenly bread spiritually; bring innocence to the altar.
So far is it from the truth that Augustine ever thought that Judas and the other faithless ones had eaten the very Body of Christ, that he even said elsewhere that Judas had eaten the bread