Taxo™ ONPG Discs are used for the detection of lactose fermenters, especially those that do not promptly ferment lactose in some routine identification media such as Triple Sugar Iron Agar (TSI Agar) or Kligler Iron Agar

These discs are 6 mm discs made from high-quality absorbent paper impregnated with approximately 100 µg of o-nitrophenyl-β-D-galactopyranoside per disc.