NURSING EXAM QUESTIONS
MICROBIOLOGY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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activity of microorganisms by reducing the chemical reaction and action of enzymes.
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cheapest form of radiation for food preservation.
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concentrations of an antibiotic, thus resistant strains finally develop.
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hazard is reported and possible control measures are identified.
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Detailed explanation-1: -The lower the temperature, the slower the enzyme activity, chemical reactions, and microbial growth. The term psychrophile is applied only to microorganisms growing from-5 to 20°C with an optimum growth temperature between 12 and 15°C. Another important term for refrigerated (0–7°C) foods is psychrotrophs.
Detailed explanation-2: -Lower temperatures lead to slower chemical reactions. Enzymes will eventually become inactive at freezing temperatures but will restore most of their enzyme activity when temperatures increase again, while some enzymes lose their activity when frozen.
Detailed explanation-3: -Low temperatures usually inhibit or stop microbial growth and proliferation but often do not kill bacteria. Refrigeration (4ºC) and freezing (-20ºC or less) are commonly used in the food, pharmaceuticals and biotechnology industry.
Detailed explanation-4: -Freezing prevents the growth of most foodborne microorganisms and refrigeration temperatures slow down the growth of microorganisms. Refrigeration below 5 °C effectively retards the growth of many foodborne pathogens. The cooling rate is important in controlling the growth of microorganisms.
Detailed explanation-5: -This is because at low temperatures, the molecules have low kinetic energy. The low speeds of the molecules means that the rate of substrates colliding with the enzyme’s active sites is also quite low.