Do not labor for the food which perishes, but for the food which endures to everlasting life, which the Son of Man will give you, because God the Father has set His seal on Him." NKJV John 6:27
I am an Evangelical but have been worshiping in a high church for many years mainly because my friends worship there too. I know the doctrine of transubstantiation which teaches that the bread and wine literally change into Jesus' flesh and blood in the Eucharist. Most defenders of this teaching use John 6 as the main evidence. But in v27 Jesus not to work for FOOD WHICH PERISHES: i.e food that will rot and mould, but work for the food that will endure to eternal life. This is the "food" which Jesus says he'll give.
My question is: how does one who believes in transubstantiation go about understanding v27, considering that the consecrated bread in the Eucharist WILL eventually "perish"/mould/rot over time if left unconsumed. How can Jesus be referring to the Eucharist as his "food", when he says that HIS food will NOT perish (unlike the consecrated bread)?
I am not looking for an argument, I am just interested in how Catholics interpret this verse.