The word" deteriorate" can be replaced by ______.

A．necessary chemical preservatives are totally absent from it
B．it is infected with yeasts, moulds and bacteria
C．heat sterilization destroys infections present in it
D．it isn't fit for storage

A．cleaning and trimming raw food
B．sterilizing canned food
C．blanching vegetables that are to be canned
D．printing labels and packing the tins into boxes