food poisoning is a kind of illness & bacteria can cause people to become ill ->  bacteria / viruses cause food poisoning  bacteria / viruses cause food poisoning & if something causes something else then then reducing that something will prevent that something else ->  reducing bacteria in food prevents food poisoning in people  adding heat to something kills viruses / bacteria in that something & killing something reduces the amount of that something ->  adding heat to something reduces the bacteria in that something  reducing bacteria in food prevents food poisoning in people & adding heat to something reduces the bacteria in that something ->  adding heat to food prevents food poisoning  adding heat to food prevents food poisoning & cooking food requires adding heat energy to the food ->  cooking food prevents food poisoning  cooking food prevents food poisoning & preventing something is a kind of method of protection against that something -> cooking food protects against food poisoning