Practical control of Salmonella: Which common processes can effectively kill Salmonella species in water or food handling?

Introduction / Context:
Salmonella species are important enteric pathogens transmitted by contaminated food and water. Understanding which routine public health interventions inactivate Salmonella helps in prevention strategies and outbreak control.

Given Data / Assumptions:

• Processes considered: pasteurisation, chlorination, and boiling.
• Appropriate time–temperature or concentration–contact parameters are applied.
• Focus is on killing organisms, not merely inhibiting growth.

Concept / Approach:
Salmonella are non-spore-forming Gram-negative bacilli and are susceptible to moist heat. Standard pasteurisation regimens for milk (e.g., 72°C for 15 seconds, high-temperature short-time) kill Salmonella. Adequate chlorination of potable water (maintaining free chlorine residual with suitable contact time) inactivates enteric bacteria, including Salmonella. Boiling water provides even more robust thermal inactivation. Thus, all listed measures can kill Salmonella when properly applied.

Step-by-Step Solution:
Confirm that Salmonella lack heat-resistant spores. Apply principles of thermal death time to pasteurisation and boiling. Recognize chlorine’s bactericidal action through oxidative damage to cellular components. Conclude that all three methods are effective.

Verification / Alternative check:
Food safety standards and water treatment guidelines explicitly list Salmonella among organisms controlled by these processes when validated parameters are met.

Why Other Options Are Wrong:

• Each single method is effective but listing only one ignores the others.
• Refrigeration alone: Slows growth but does not reliably kill Salmonella.

Common Pitfalls:
Assuming refrigeration or freezing is bactericidal; these are primarily bacteriostatic for many enteric pathogens.

Final Answer:
All of these.