MacConkey Agar with Sorbitol (SMAC) is a selective and differential medium used for the detection and isolation of enterohemorrhagic Escherichia coli O157:H7, a clinically significant sorbitol-negative strain.

This medium replaces lactose with D-sorbitol, enabling differentiation based on sorbitol fermentation. Most non-pathogenic E. coli ferment sorbitol, producing pink to red colonies, while E. coli O157:H7 typically does not ferment sorbitol, appearing as colorless or transparent colonies.

The SMAC formulation incorporates bile salts and crystal violet to suppress Gram-positive bacteria, ensuring selective recovery of Gram-negative enteric organisms.

Each plate is crafted from optically clear, heavy-duty polystyrene for distortion-free viewing and reliable stacking. Breathable packaging minimizes condensation, extending plate quality and shelf stability.

Features and Benefits:
• Selective and differential for E. coli O157 detection (sorbitol negative)
• Clear visual differentiation between sorbitol fermenters and non-fermenters
• Suppresses Gram-positive bacteria for cleaner isolation
• Heavy-duty, optically clear polystyrene plates reduce distortion and breakage
• Raised stacking rings improve stability during storage and transport
• Breathable packaging prevents moisture buildup and maintains media integrity
• Ideal for clinical, food safety, and environmental testing laboratories