Question:
Which of the following is used as test organism to determine the sterilising effect of in-container sterilisation?
Which of the following is used as test organism to determine the sterilising effect of in-container sterilisation?
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Remember: M. tuberculosis is the index for Pasteurization (low heat), whereas C. botulinum is the index for Sterilization (high heat).
Updated On: Jul 23, 2026
- Mycobacterium tuberculosis
- E. coli
- Staphylococcus aureus
- Clostridium botulinum
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Verified By Collegedunia
The Correct Option is D
Solution and Explanation
Step 1: Understanding the Concept:
In-container sterilization is a preservation process where milk is filled into containers (bottles or cans) and subjected to intense heat treatment to achieve shelf stability.
The primary objective of this thermal process is the destruction of pathogenic and spoilage-causing bacteria.
To validate the safety and effectiveness of such a process, a "test organism" or "index organism" is chosen based on its resistance to heat and its public health significance.
Step 2: Detailed Explanation:
Thermal processing in the dairy and canning industries is fundamentally designed around the destruction of Clostridium botulinum.
This bacterium is an anaerobic, spore-forming pathogen that produces the highly potent botulinum toxin under anaerobic conditions.
Its spores are remarkably heat-resistant, making it the benchmark for determining the minimum heat treatment required for low-acid foods like milk.
The industry follows the "12D concept," which aims for a theoretical 12-log reduction in the population of C. botulinum spores.
While Mycobacterium tuberculosis (Option A) was historically used as the index organism for pasteurization because it was the most heat-resistant non-spore-forming pathogen, it is far less resistant than the spores targeted in sterilization.
E. coli (Option B) and Staphylococcus aureus (Option C) are also vegetative cells that are easily destroyed at temperatures well below those used for sterilization.
In specialized commercial sterility testing, thermophilic spores like Geobacillus stearothermophilus (formerly Bacillus stearothermophilus) are sometimes used because they are even more heat-resistant than C. botulinum, but in terms of public health safety and the fundamental definition of the "sterilizing effect," Clostridium botulinum remains the critical test organism.
The thermal death time (TDT) and F-value calculations in dairy engineering are primarily based on the heat destruction kinetics of these spores.
Step 3: Final Answer:
The test organism used is Clostridium botulinum.
In-container sterilization is a preservation process where milk is filled into containers (bottles or cans) and subjected to intense heat treatment to achieve shelf stability.
The primary objective of this thermal process is the destruction of pathogenic and spoilage-causing bacteria.
To validate the safety and effectiveness of such a process, a "test organism" or "index organism" is chosen based on its resistance to heat and its public health significance.
Step 2: Detailed Explanation:
Thermal processing in the dairy and canning industries is fundamentally designed around the destruction of Clostridium botulinum.
This bacterium is an anaerobic, spore-forming pathogen that produces the highly potent botulinum toxin under anaerobic conditions.
Its spores are remarkably heat-resistant, making it the benchmark for determining the minimum heat treatment required for low-acid foods like milk.
The industry follows the "12D concept," which aims for a theoretical 12-log reduction in the population of C. botulinum spores.
While Mycobacterium tuberculosis (Option A) was historically used as the index organism for pasteurization because it was the most heat-resistant non-spore-forming pathogen, it is far less resistant than the spores targeted in sterilization.
E. coli (Option B) and Staphylococcus aureus (Option C) are also vegetative cells that are easily destroyed at temperatures well below those used for sterilization.
In specialized commercial sterility testing, thermophilic spores like Geobacillus stearothermophilus (formerly Bacillus stearothermophilus) are sometimes used because they are even more heat-resistant than C. botulinum, but in terms of public health safety and the fundamental definition of the "sterilizing effect," Clostridium botulinum remains the critical test organism.
The thermal death time (TDT) and F-value calculations in dairy engineering are primarily based on the heat destruction kinetics of these spores.
Step 3: Final Answer:
The test organism used is Clostridium botulinum.
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