Question

What is food poisoning? Explain how each of these methods helps to keep food safe: (a) refrigeration (b) boiling/pasteurisation of milk (c) adding sugar in jams.

Equal samples of fresh milk were kept at four temperatures for 1 day, and the number of bacterial colonies grown from each was counted (see bar graph). (a) At which temperature did bacteria grow most? (b) How many times more colonies were there at 37 °C than at 4 °C? (c) What advice would you give a shopkeeper about storing milk, and why?