Which of the following statements about Robert Koch's germ theory of disease is incorrect?

Explanation

Koch's postulates state that a specific microorganism should be found in all cases of the disease (A), can be isolated and grown in pure culture (B), and that this pure culture should cause the disease when introduced into a healthy susceptible host (contrary to C). Additionally, the organism must be recoverable from the experimentally infected host (D). Therefore, option C is incorrect because a pure culture must be able to produce the disease upon inoculation.