Correct Answer: B

Rationale: The correct answer is B: Disinfection. Disinfection is not a method for food preservation but rather a process of destroying harmful microorganisms on surfaces. A: Pasteurization involves heating food to kill pathogens, preserving the food. C: Irradiation uses radiation to kill bacteria and parasites, extending shelf life. D: Ultrahigh-temperature pasteurization involves heating food at very high temperatures to extend shelf life. In summary, disinfection is not a method used to preserve food but rather to clean surfaces.

Correct Answer: A

Rationale: The correct answer is A: cultivating on artificial media and biochemical identification. This method is appropriate for diagnosing listeriosis because it allows for the isolation and growth of Listeria species on selective media, followed by biochemical tests to confirm the identity. Serological diagnosis with ELISA (choice B) is not as specific for Listeria and may yield false positives. Choice C, serological diagnosis with agglutination hype Widal, is not typically used for listeriosis diagnosis. Cultivating in cell cultures (choice D) is not the primary method for diagnosing listeriosis as it is less specific compared to cultivating on artificial media and biochemical identification.

Correct Answer: C

Rationale: The correct answer is C: To determine the antibiotic susceptibility of microorganisms. PCR is not suitable for determining antibiotic susceptibility as it is a technique used to amplify DNA/RNA, not to test for antibiotic resistance. To prove latent infection (A), PCR can be used to detect low levels of pathogens. For rapid diagnosis of infectious diseases (B), PCR is commonly used due to its sensitivity and specificity. To demonstrate DNA and RNA molecules (D), PCR is ideal as it can amplify and detect specific sequences. Therefore, choice C is incorrect as PCR is not designed for determining antibiotic susceptibility.

Correct Answer: A

Rationale: The correct answer is A: Bacillus anthracis. The black, painless carbuncle with peripheral vesicular rash is characteristic of cutaneous anthrax. Microscopy showing non-motile Gram-positive rods with a capsule aligns with Bacillus anthracis. The other choices can be eliminated: B: Staphylococcus aureus does not typically form a black lesion or have a capsule. C: Clostridium perfringens causes gas gangrene, not the described lesion. D: Bacillus subtilis is not associated with the specific clinical presentation mentioned.

Correct Answer: B

Rationale: The correct answer is B: Biological oxidation. Haematrophic bacteria obtain energy through biological oxidation, where they break down organic compounds to generate ATP for cellular processes. This process involves the transfer of electrons from the substrate to an electron transport chain to produce energy. Heat production (A) is a byproduct of metabolism, not the primary way to obtain energy. In biosynthetic reactions (C), energy is utilized rather than generated. Cultivation in culture media (D) is a method of growing bacteria but does not directly provide energy. Therefore, the correct answer is B as it aligns with the metabolic process of haematrophic bacteria.