【单选题】Food which is kept too long decays because it is attacked by yeasts (酵母菌), moulds (霉) and bacteria (细菌). The canning process, however, seals the product in a container so that no infection can reach i...
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