True statement regarding diphtheria is
High-Yield Explanation
Toxin production is influenced by the concentration of iron in the medium. The optimum level of iron for toxin production is 0.1 mg/l, while a concentration of 0.5mg/l inhibits the formation of the toxin. Reference: Textbook of Microbiology; Anathanarayan and panicker's; 10th edition; Page no: 240