ISO 2002 Salmonella method updates: Which statements correctly reflect changes in the ISO 2002 method for Salmonella detection in foods?

Introduction / Context:
Standard methods evolve to improve recovery of stressed Salmonella and reduce background growth. The ISO 2002 revisions modernized enrichment and isolation steps to increase sensitivity and specificity across diverse foods.

Given Data / Assumptions:

• Pre-enrichment and selective enrichment broths are critical for resuscitating injured cells.
• Selective agars differentiate Salmonella colonies from competing flora.
• The question lists three procedural updates.

Concept / Approach:
MKTTn provides improved selectivity over SC while recovering stressed cells; RVS refines the RV formulation with soya peptone to enhance growth of sublethally injured Salmonella; XLD as the primary isolation agar offers clearer differentiation (hydrogen sulfide production on a contrasting background) compared to BGA in many matrices.

Step-by-Step Solution:
Evaluate each statement versus ISO 2002 method details. Confirm replacements: SC → MKTTn and RV → RVS to enhance selectivity/recovery. Confirm XLD as first-choice isolation medium. Select “All of these.”

Verification / Alternative check:
Validation studies show improved detection rates using MKTTn/RVS and XLD for first isolation, with confirmatory testing on secondary media.

Why Other Options Are Wrong:
Single statements miss the holistic change set; “None” contradicts documented method updates.

Common Pitfalls:
Using legacy SC/RV/BGA alone may under-recover stressed cells from processed foods.

Final Answer:
All of these.