Kosher is a modern Talmudic [read, "rabbinic"] teaching, and does not quite line up with actual scripture [KJB], yet, none the less, I do obey that which scripture [KJB] teaches.
What does this mean, then, in response to your excellent question.
It is written:
Psalms 77:13 KJB - Thy way, O God, is in the sanctuary: who is so great a God as our God?
Therefore, every single doctrine of Jesus [the way, John 14:6], even the whole plan of Redemption, is found therein. This would include the doctrine of diet.
You are absolutely correct about the blood (and fat, and diseased, strangled, died of itself, etc) still being in those modern "shambles" (markets).
God forbids from those things to be consumed (even from Genesis, at the beginning) even today, especially by the follower of Jesus Christ.
Acts 10,11 &15 to give just a few references, more in another thread, another time, with a few examples to follow.
Acts 15:20 KJB - But that we write unto them, that they abstain from pollutions of idols, and from fornication, and from things strangled, and from blood.
This is repeated on several occasions, see also Acts 15:29, 21:25. Acts 15 is citing the OT health laws of God, Leviticus 7:26, 17:12-14, 19:26; Deuteronomy 12:16,23, etc. In fact, Peter cites Leviticus 11:44,45, 20:7 in 1 Peter 1:15,16, and that is right in the middle of God's health laws, which deals with Holiness, for what one eats, consumes, affects the mind, character and body and health.
3 John 1:2 KJB - Beloved, I wish above all things that thou mayest prosper and be in health, even as thy soul prospereth.
See also:
1 Corinthians 10:31 KJB - Whether therefore ye eat, or drink, or whatsoever ye do, do all to the glory of God.
1 Corinthians 6:20 KJB - For ye are bought with a price: therefore glorify God in your body, and in your spirit, which are God's.
The problem is, most of Christianity is not obeying God, and is causing physical and spiritual drunkeness, and darkness and blindness.
They are ignorant of God's way, see Hosea 4:1-6 KJB and will perish in such, not because light and truth was not sent, but because men loved darkness, rather than light, sin more than righteousness.
Read carefully, 1 Corinthians 10:6,11 with Psalms 78:17-32 KJB. Those who continue to rebel against the light, will receive the wrath of God, even the seven last plagues, even as now the diseased flesh that is shovelled into their mouths, brought serious flu's, coming out of their noses, slaying many.
The sanctuary teaches us that health reform and diet, going back to eden, should be progressive.
Outside the sanctuary was the wilderness and the lost world, eating and drinking to the god of their bellies (1 Corinthians 6:13; Philippians 3:19), eating all manner of blood, diseased, unclean, etc.
But once a person became a follower of Christ (1 Corinthians 10:4), they entered by faith into the Courtyard, which was in service until the ascension of Jesus Christ, which taught that only the clean could be eaten, temperately, no blood, no fat, no strangled, no diseased, had to be sodden, and fired and dried (like jerky), not whole slabs of flesh (given to shorten the sinners lifespan (Genesis 9:3-5).
Once Jesus Christ ascended, the Courtyard transitioned into the Holy Place (Revelation 1:1-20, 4:1-11, 5:1-14, etc.) the diet was to change again, for in the Holy Place Jesus eats no flesh whatsoever, and we are to follow the Lamb whithersoever He goeth (by faith), yet, there was cooked grain (bread), olive oil, herbs (incense), showing the change in diet. Once Jesus transitioned to the Most Holy Place (end 2,300 day/years Daniel 8:13-14,26; Revelation 8:13-15; and end of 1,335 day/years Daniel 12:12. The antitypical day of Atonement, Leviticus 16 & 23, etc.), the diet moves once again to a more raw fresh diet, leaving behind heavy cooking, since there was the manna, the almond buds, the leaves, Eden restored diet.
Yet, because darkness crept in, most was forgotten, not followed, until the Most Holy Place was opened in Heaven, Daniel 7:9,10,13,22; Revelation 3:7,8, 11:19 KJB etc.
Yet, God is merciful, and longs to heal our diseases, diets, corrupt lifestyles.
We, as Seventh-day Adventists, have the mandate from Jesus Himself:
Matthew 10:8 KJB - Heal the sick, cleanse the lepers, raise the dead, cast out devils: freely ye have received, freely give.
Therefore I don't eat flesh any longer, for about 8-9 years now, and my diet is closer to the edenic (I also have a garden, but that's another study in the sanctuary), fruits and veggies, Health reformer.