Complex sentence: Plants from the ground that are not washed properly may contain B12 from bacteria in the soil, often from faeces; drinking water may also be contaminated with B12-producing bacteria, particularly in the developing world.
Split into simpler sentences: Plants from the ground that are not washed properly may contain B12 from bacteria in the soil, often from faeces. Drinking water may also be contaminated with B12-producing bacteria, particularly in the developing world.