Well, this is an interesting question. Animal-derived foods are a primary source of B12 as they eat food contaminated with bacteria. Which foods can boost vitamin intake?
Meat Products – Beef, Liver
Fish – Tuna, Clams, Salmon
Dairy Products – milk, yoghurt and cheese
Eggs
Fortified Foods – Cereals,
Found in some algae and fortified foods like nutritional yeast.
Reliable vegan plant-based sources of B12 are foods fortified with B12 or a supplement.
Fortified breakfast cereal
Fortified Plant Milk
Nutritional yeast
Yeast extract – Marmite
Fortified Foods – Check nutrition information on the packaging to make sure that they are fortified and the level added.