Eating "unclean animals" is prohibited in Leviticus 11, as is eating the blood of an animal, as "the life is in the blood"; this chapter also contains as the prohibition against seafood that doesn't have fins and scales.
The prohibition against milk and meat together is based on the commandment not to boil a kid in its mother's milk (Ex 23:19); it was expanded by the rabbis to "build a fence around the Torah."
For a complete understanding: see Kashrut
shalom b'SHEM Yah'shua HaMashiach Adonai