Nokea
All of the following are methods for food preservation except
- A. Pasteurization
- B. Disinfection
- C. Irradiation
- D. Ultrahigh-temperature pasteurization
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.
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The causative agent of the pertussis (also known as whooping cough) morphologically appears as:
- A. Gram positive bacillus
- B. Gram negative coccobacillus
- C. Long Gram-negative rod shaped bacterium
- D. None of the above
Correct Answer: B
Rationale: The correct answer is B: Gram negative coccobacillus. Bordetella pertussis, the causative agent of pertussis, is a gram-negative coccobacillus. This is because it is a small, rod-shaped bacterium that appears both as a bacillus (rod-shaped) and a coccus (spherical) shape. It does not retain the crystal violet stain in the Gram staining process, indicating its negative gram nature. Choice A is incorrect because pertussis is not a gram-positive bacillus. Choice C is incorrect because pertussis is not a long gram-negative rod-shaped bacterium. Choice D is incorrect as the other options do not accurately describe the morphology of Bordetella pertussis.
Which of the following bacteria is responsible for causing the plague?
- A. Yersinia pestis
- B. Clostridium difficile
- C. Neisseria gonorrhoeae
- D. Pseudomonas aeruginosa
Correct Answer: A
Rationale: The correct answer is A: Yersinia pestis. Y. pestis is responsible for causing the plague, a severe infectious disease. This bacterium is transmitted via fleas from rodents to humans. It causes bubonic, septicemic, and pneumonic plague. Clostridium difficile causes gastrointestinal infections, Neisseria gonorrhoeae causes gonorrhea, and Pseudomonas aeruginosa can cause various infections but not the plague.
Which bacteria are known for causing urinary tract infections?
- A. Escherichia coli
- B. Salmonella enterica
- C. Neisseria gonorrhoeae
- D. All of the above
Correct Answer: D
Rationale: The correct answer is D, "All of the above." Escherichia coli is the most common bacteria causing UTIs due to its ability to colonize the urinary tract. Salmonella enterica and Neisseria gonorrhoeae are not typically associated with UTIs. Therefore, by process of elimination, since A is correct, B and C are incorrect.
Which type of bacteria can survive in both aerobic and anaerobic environments?
- A. Obligate aerobes
- B. Facultative anaerobes
- C. Obligate anaerobes
- D. Microaerophiles
Correct Answer: B
Rationale: Certainly! The correct answer is B: Facultative anaerobes. Facultative anaerobes can survive in both aerobic and anaerobic environments due to their ability to switch between utilizing oxygen for respiration in aerobic conditions and utilizing fermentation or anaerobic respiration in anaerobic conditions. This flexibility allows them to thrive in diverse environments.
Explanation for incorrect choices:
A: Obligate aerobes require oxygen for respiration and cannot survive in anaerobic environments.
C: Obligate anaerobes can only survive in the absence of oxygen and would not thrive in aerobic conditions.
D: Microaerophiles require low levels of oxygen to grow and are not as versatile in adapting to varying oxygen levels compared to facultative anaerobes.
What is the most appropriate method for diagnosis of listeriosis
- A. cultivating on artificial media and biochemical identification
- B. serological diagnosis with ELISA
- C. serological diagnosis with agglutination hype Widal
- D. cultivating in cell cultures
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.