Where can we find B12 in nature?

B12 can be found in many of our natural animal food sources such as: fish, milk/milk products, eggs, meat and poultry. For vegetarians a great source of vitamin B12 is found in fortified cereals. Current studies show that there has been considerable research into finding plant sources of B12, in products such as seaweeds and soya products, but no significant plant sources have been found. Popular belief is that most plant derived B12 isn't able to be used by the human body and doesn't work.