Microbiological Food Safety Criteria under FSSAI regulations:
Under Appendix B (Table 2B - Microbiological Food Safety Criteria for Milk and Milk Products, Infant Formula and Follow-up Formula) of the Food Safety and Standards Regulations:

• Salmonella is a zero-tolerance enteric pathogen in dairy foods.
• For Infant Milk Food, Infant Formula, and Processed Cereal-based Complementary Foods, the regulatory standard stipulates: Salmonella must be 'Absent in $25\text{ g}$' across all sample units ($n = 5; c = 0$).

Codex Alimentarius HACCP Seven Principles sequence:

• Principle 1 (D): Conduct a hazard analysis (identify potential biological, chemical, physical hazards).
• Principle 2 (A): Determine the Critical Control Points (CCPs) using a decision tree.
• Principle 3 (C): Establish critical limits for each CCP.
• Principle 4 (B): Establish a monitoring system for each CCP.
• Principle 5: Establish corrective actions.
  6. Principle 6: Establish verification procedures.
  7. Principle 7: Establish record-keeping and documentation.

Wastewater treatment bioreactor engineering in dairy plants:
(A), (B), (C) are incorrect expansions.
(D) UASB stands for 'Upflow Anaerobic Sludge Blanket'. It is a high-rate anaerobic wastewater treatment technology widely deployed for treating high-BOD dairy and food processing effluents. Wastewater enters the bottom of the reactor and flows upwards through a dense bed of granular anaerobic microbial sludge, converting organic matter into methane-rich biogas and treated effluent.