Daily lessons coming soon
Beginning Monday 20 April, BBC Bitesize will publish daily online lessons for all ages. We'll also have a new dedicated TV channel full of learning content, podcasts on BBC Sounds and loads of educational video on iPlayer.
Pathogens are disease-causing viruses, bacteria, fungi or protists, which can infect animals and plants. Humans have an immune system, which can defend them from pathogens.
Greg James describes the effects of bacterial growth and how to prevent foodborne illness