Given what we know about evolutionary biology, we expect to find the largest number of endemic species in which of the following geological features, which have existed for at least a few million years?

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#Question id: 35937

#XL - U Food Technology

Which of the following are true regarding D-value (Decimal reduction time) in microbial death kinetics?

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#Question id: 35938

#XL - U Food Technology

Which of the following statements are correct about the Z-value in microbial thermal death kinetics?

A. Z-value is the temperature increase required to reduce the D-value by one log cycle.

B. A higher Z-value indicates that the microorganism is more sensitive to temperature changes.

C. Z-value helps in comparing the thermal resistance of different microorganisms.

D. Z-value is independent of the heating medium.

E. Z-value can be used to optimize time-temperature combinations in thermal processing.

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#Question id: 35939

#XL - U Food Technology

A bacterial culture has an initial population of 1×10⁴cells/mL. The population doubles every 30 minutes. What will be the population (in cells/mL) after 2 hours?

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#Question id: 35940

#XL - U Food Technology

In a batch culture, the specific growth rate (𝜇) of a microbe is 0.693 h^-1. What is the doubling time (in hours) of this organism?

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#Question id: 35941

#XL - U Food Technology

A microbial population declines from 1×10⁸CFU/mL to 1×10⁴CFU/mL in 30 minutes during thermal processing. Assuming first-order death kinetics, calculate the decimal reduction time (D-value) in minutes.

(Use: 𝑁=𝑁₀×10^{−𝑡 / 𝐷})

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#Question id: 35942

#XL - U Food Technology

A microorganism has a D-value of 5 minutes at 121°C. How much time (in minutes) is required to achieve a 6-log reduction at this temperature?

( Time = D × log reduction)