Enteric pathogen recovery — Which of the following serve as enrichment media for isolating Salmonella from clinical or food samples?

Introduction / Context:
Detecting Salmonella in stool and food requires suppressing commensals while allowing target organisms to multiply. Enrichment broths are designed to favor Salmonella growth over competing flora, improving sensitivity before plating on selective agars.

Given Data / Assumptions:

• Tetrathionate and selenite compounds inhibit many coliforms while allowing Salmonella to grow.
• Brilliant green dye further suppresses Gram-positive bacteria and some Gram-negatives.
• The aim is pre-enrichment/enrichment prior to selective plating (e.g., XLD, HE, SS agar).

Concept / Approach:
Tetrathionate broth and brilliant green tetrathionate broth inhibit competing intestinal flora by using tetrathionate and dye, respectively. Selenite-F broth similarly suppresses commensals and enriches Salmonella. Because all three broths are established enrichment media used in protocols for Salmonella recovery, the correct choice is “All of these.”

Step-by-Step Solution:

Verification / Alternative check:
Method standards (e.g., food microbiology manuals) list these broths in validated workflows, confirming their role as enrichment media.

Why Other Options Are Wrong:

• Selecting only one medium reduces recovery because different strains may prefer different enrichments; using multiple enrichments increases yield.

Common Pitfalls:
Skipping enrichment or over-incubating, which can allow overgrowth of competitors and reduce Salmonella recovery.

Final Answer:
All of these