The teaching of Florence is based on many things as the Fathers have expounded on it to say the whole Jєωιѕн law is defunct.  But Scripture cuts to the chase for us.  
Acts 10:9-16
Peter’s Vision
⁹ About noon the following day as they were on their journey and approaching the city, Peter went up on the roof to pray. ¹⁰ He became hungry and wanted something to eat, and while the meal was being prepared, he fell into a trance. ¹¹ He saw heaven opened and something like a large sheet being let down to earth by its four corners. ¹² It contained all kinds of four-footed animals, as well as reptiles and birds. ¹³ Then a voice told him, “Get up, Peter. Kill and eat.”
¹⁴ “Surely not, Lord!” Peter replied. “I have never eaten anything impure or unclean.”
¹⁵ The voice spoke to him a second time, “Do not call anything impure that God has made clean.”
¹⁶ This happened three times, and immediately the sheet was taken back to heaven.

Its the same principle and applies to animals and men insofar as the Mosaic Law is concerned.  The passage spoke of animals included in the Mosaic Law. The problem with Peter is that he respected only those who were circuмcised out of respect and fear of the Jєωs--more Jєωιѕн law.  Paul resisted him to his face because, as Scripture said, "he was to be blamed".  
Circuмcision belonged to the old law and was no longer applicable since it was replaced by Baptism.  What Paul objected to was identical to what Peter was shown in the scroll.  The Mosaic Law ceased.  

Paul understood that the Old Law had ceased.  The Old Covenant is out.  The new law of love is the New Covenant and is binding.  Practicing the Old Law is damnable according to the Council of Florence since it was tolerated at first, if no one placed faith in it, but then it was abolished and makes one practicing it in any of its forms, anathema.

Oh!  Butter-sauteed abalone!  Crispy bacon!   Fried catfish!  Steamed Dungeness crab!  Crawfish boils!  Seafood gumbo!  "Boiled"[×] lobsters!  Raw oysters![†]  Pulled pork!  Shrimp & grits!  Uni!  Yaaay!

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Note ×: The classic book Joy of Cooking (1973 paperback) fussily insists that in this instance, the cooking method is technically not "boiling" but poaching.
 
Note †: Harvested with appropriate caution, heeding any quarantines by  health officials that might be in effect at the time; customary rules invoking the presence or absence of 'R' in the name of a month are dangerously inadequate.