Enteric Bacteria Isolation and Differentiation: Selective and differential plating of Gram-negative enterics based on lactose fermentation (pink/red fermenters such as Escherichia coli, Klebsiella, Enterobacter; colorless non-fermenters such as Salmonella, Shigella), using bile salts #3, crystal violet, lactose, and neutral red.

Clinical Stool and Urine Cultures: Recovery of enteric pathogens and uropathogens (e.g., Escherichia coli, Klebsiella, Pseudomonas aeruginosa) while inhibiting Gram-positive flora.

Coliform Testing in Food and Water: Enumeration and differentiation of coliforms (e.g., Escherichia coli, Enterobacter, Klebsiella) for HACCP and regulatory compliance.

Environmental Monitoring: Detection of fecal contamination via lactose-fermentation profiles in surface, wastewater, and process-hygiene samples.

Selective Recovery from Mixed Flora: Inhibition of Gram-positive organisms with bile salts #3 and crystal violet to facilitate Gram-negative isolation from polymicrobial specimens.

Phenotypic Confirmation of Lactose Fermentation: Verification of fermentation status (acid/neutral red response and bile precipitate) to support identification workflows.

Pharmaceutical and Cosmetic QC: Routine monitoring for Gram-negative contamination and differentiation of objectionable organisms in raw materials and finished products.

Enteric Pathogen Screening: Isolation of non-lactose fermenting pathogens (e.g., Salmonella, Shigella) following enrichment or direct plating.

Suppression of Proteus Swarming: Use of bile salts to reduce swarming by Proteus spp., enabling discrete colony isolation.