GPEcp and PAC standard were adjusted to pH 7.1, dilutions were prepared and added to molten agar to achieve 1.0, 0.33, 0.11, 0.03, or 0.012 mg of proanthocyanidin (B2 equivalents) per mL medium. A. muciniphila culture (OD = 0.875) was diluted 10-3 and 10-4 and 30 μL aliquots were spread on the surface of solid medium impregnated with A. GPEcp or B. PAC standard. Photograph (representative of two independent experiments) shows 24-well plates incubated under anaerobic conditions at 37°C after 3 days.