Q.58 Microbes that have their optimal growth rate near 𝟏𝟓∘𝐂 but can still grow at 𝟎∘𝐂 to 𝟐𝟎∘𝐂 are known
as
(A) mesophiles
(B) psychrotrophs
(C) psychrotolerant
(D) psychrophiles

Microbes grow best at specific temperatures, categorized into groups like psychrophiles and mesophiles. The correct answer for microbes with optimal growth near 15°C but capable from 0°C to 20°C is (B) psychrotrophs.​

Correct Answer

(B) psychrotrophs. These microbes grow at 0°C, optimal near 15°C (often 15-30°C), and up to over 25°C. They thrive in cold but not freezing environments, like refrigerated foods, causing spoilage.​

Option Breakdown

(A) Mesophiles

Grow optimally at 20-45°C (often ~37°C, human body temperature). Minimum around 10-15°C, maximum <45°C; common pathogens like E. coli. Not suited for near-freezing growth.​

(B) Psychrotrophs

Grow from 0°C, optimal 15-30°C (near 15°C fits), maximum >25°C. Called psychrotolerant; widespread in temperate areas, spoil cold-stored dairy. Matches query exactly.​

(C) Psychrotolerant

Synonym for psychrotrophs; tolerate cold (0°C growth) but prefer mesophilic optima (~15-25°C). Less standard term in some texts, but aligns with (B).​

(D) Psychrophiles

True cold-lovers: optimal ≤15°C, maximum <20°C, often <0°C minimum. Sensitive above 20°C; in polar ice, not 20°C growth.​