I would just like to point out that — while Kosher laws were not extended to cover Gentiles by the Jerusalem conference that, principally, observed/decided Gentiles did not have to become Jews to be saved — Christians should probably not be eating blood because of what they did clearly state ... so black puddings should be right out.
You are exactly right. The apostles ruled on this matter authoritatively. It is in scripture as a directive from God. Christians should not knowingly eat animal blood.
Acts 15:19-31
“Therefore I judge that we should not trouble those from among the Gentiles who are turning to God, but that we write to them to abstain from things polluted by idols, from sexual immorality, from things strangled, and from blood. For Moses has had throughout many generations those who preach him in every city, being read in the synagogues every Sabbath.”
Then it pleased the apostles and elders, with the whole church, to send chosen men of their own company to Antioch with Paul and Barnabas, namely, Judas who was also named Barsabas, and Silas, leading men among the brethren.
They wrote this letter by them:
The apostles, the elders, and the brethren,
To the brethren who are of the Gentiles in Antioch, Syria, and Cilicia:
Greetings.
Since we have heard that some who went out from us have troubled you with words, unsettling your souls, saying, “You must be circumcised and keep the law” —to whom we gave no such commandment— it seemed good to us, being assembled with one accord, to send chosen men to you with our beloved Barnabas and Paul, men who have risked their lives for the name of our Lord Jesus Christ. We have therefore sent Judas and Silas, who will also report the same things by word of mouth. For it seemed good to the Holy Spirit, and to us, to lay upon you no greater burden than these necessary things: that you abstain from things offered to idols, from blood, from things strangled, and from sexual immorality. If you keep yourselves from these, you will do well.
Farewell.
So when they were sent off, they came to Antioch; and when they had gathered the multitude together, they delivered the letter. When they had read it, they rejoiced over its encouragement.