Where in the Bible does it say that the bread and wine of communion are spiritual symbols only?

Nowhere.

Hebrews, 13:10. "We have an altar from which those still serving in the Temple cannot eat."

St. Ignatius of Antioch

"Take care, then who belong to God and to Jesus Christ - they are with the bishop. And those who repent and come to the unity of the Church - they too shall be of God, and will be living according to Jesus Christ. Do not err, my brethren: if anyone follow a schismatic, he will not inherit the Kingdom of God. If any man walk about with strange doctrine, he cannot lie down with the passion. Take care, then, to use one Eucharist, so that whatever you do, you do according to God: for there is one Flesh of our Lord Jesus Christ, and one cup in the union of His Blood; one altar, as there is one bishop with the presbytery and my fellow servants, the deacons."

-Epistle to the Philadelphians, 3:2-4:1, 110 A.D.

There are all sorts of actions all throughout the Bible that are intended to be taken symbolically. If a directed action is intended to be carried out literally, it's generally clear from the context.

The correct question should be "where in the Bible does it say that the bread and wine are anything BUT symbolic?" Particularly since human sacrifice and cannibalism weren't exactly key components of Judaism.

Some churchgoers point out that Jesus literally said: ‘This is my body,’ so they believe that the bread miraculously became his actual flesh. However, that is contrary to fact. * Jesus’ body was there in front of the faithful apostles, and so was the unleavened bread they would partake of. Clearly, Jesus was speaking symbolically, as he did many other times.—John 2:19-21; 4:13, 14; 10:7; 15:1

The Catholic Eucharist is the symbol of a defeated Christ. As the mass is taken, Christ's sacrifice is commemorated and, according to the doctrine of transubstantiation, actually repeated when the bread is eaten.

Christ is killed again and again during the mass, but His resurrection, acension, and life are minimized. This can also be seen in the use of the crucifix in Catholicism. The crucifix—an icon of the cross with Jesus still hanging on it—only commemorates the death of Christ, ignoring the resurrection that proves His victory over death and Satan.

JESUS says, do this in Remembrance of Me, Its SYMBOLIC friend....

But with your example, the drink is not the blood of a blood sacrifice. At the Last Supper, Jesus said, "This is my body, which is broken for you" and "This is the blood of the New testament, which is shed for you." BUT, Jesus was right there, and present in His living Human body, yet unbroken, and with His blood unshed and still flowing through His veins. Jesus also said He was the bread of life, and the light of the world. Now ask me again which words are symbolic, and which are factually true.

All the books of the Bible were written before people started the 'communion'. If you do what is written in the books of the Bible, why most of the Christians don't have Luke 10:25-37 in their Bibles.

Weak. Stick to the classical arguments.

Not read what Christ said in John 6?

In the sense that it is NOT the LITERAL body of Christ, then it is SPIRITUAL, and in the sense

that we don't drink literal blood....not enough of it! for one thing....it is SPIRITUAL.

We partake of both the body and the blood of Jesus spiritually.

God IS SPIRIT.

nowhere, jesus says "my flesh is food INDEED"