My understanding is that the Jewish Rabbis who wrote the OT
Rabbis wrote the Mishnah and the Gemara not the OT.
The JW believe that the law covenant did not apply to Gentiles and further the same Mosaic law was abolished by the death of Jesus except the Noachide law pertaining to blood which preceded the law of Moses as stated in the Chumash. According to the “NT” command “Keep abstaining from blood,” JW believe this to mean that blood transfusions, eating blood or using some blood products such as those containing whole blood are forbidden. TD made an interesting rebuttal based on Pekuah Nephesh and God’s Law to Israel referring to the Torah: “ That you may LIVE by them. But this does not invalidate the command to Christians that they should abstain from blood as JW see it. According to today’s Pharisaic Judaism, any command can be broken to save a life except for murder, idolatry and adultery. JW believe that none of God’s commands can be broken including the one on blood as it applies to Christians even to “save a life”. TD argued that Jesus pointed to king David when he and his men ate the loaves of presentation which was not lawful to show his disciples did not sin by picking grain on the Sabbath. However, Jesus never said that this applied to making an allowance for Christians eating blood. Nor is it logical to conclude that.
Also, Karaite Jews reject the Talmudic interpretation of the OT as inspired or as the oral law. For example, they eat meat and dairy together.