Sterilization vs pasteurization — Which listed process does NOT reliably kill bacterial endospores (highly resistant dormant forms)?

Introduction / Context:
Bacterial endospores (e.g., Bacillus, Clostridium) are among the most heat-resistant forms of life, requiring rigorous sterilization conditions for destruction. Understanding which methods are sporicidal is essential for laboratory safety, clinical practice, and food processing. This question distinguishes sterilization from sub-sterilization heat treatments like pasteurization.

Given Data / Assumptions:

• Endospores demand high temperature and/or prolonged exposure or strong chemical oxidants.
• Options include processes with markedly different lethality.
• We seek the method that does not reliably kill endospores under standard conditions.

Concept / Approach:
Sterilization = complete destruction of all microbial life including spores and some viruses. Pasteurization = significant pathogen reduction, not sterility. Autoclaving (121°C saturated steam, ~15 psi, ≥15 minutes), hot air sterilization (e.g., 160–170°C for 2 hours), and incineration are sporicidal. Pasteurization (e.g., 63°C for 30 min or 72°C for 15 sec) does not inactivate spores.

Step-by-Step Solution:

Verification / Alternative check:
Sterilization indicators (e.g., Geobacillus stearothermophilus spores) are used to validate autoclaves, confirming sporicidal efficacy. No such spore kill is expected from pasteurization standards.

Why Other Options Are Wrong:

• Autoclave: specifically validated to kill spores.
• Incineration: high temperature ash-forming process; certainly sporicidal.
• Hot air sterilization: dry heat protocols achieve spore kill with adequate time.

Common Pitfalls:
Assuming any heat process equals sterilization; pasteurization improves safety but does not produce sterility or spore kill.

Final Answer:
Pasteurization