Bifidobacterium longum subsp. infantis Culture

Bacterial culture conditions were maintained as previously described [9 (link)]. Bifidobacterium longum subsp. infantis ATCC^® 15697™ (B. infantis) was obtained from the American Type Culture Collection (ATCC, Middlesex, UK). and the strain was stored in deMan Rogosa Sharpe (MRS) (Difco, Sparks, MD, USA) broth containing 50% glycerol at −80 °C. The strain was cultured twice in MRS media supplemented with L-cysteine (0.05% w/v) prior to use and was routinely grown overnight at 37 °C under anaerobic conditions generated using the Anaerocult A system (Merck, Dannstadt, Germany). For assays, B. infantis was incubated alone or in combination with each powder for 1 h and the bacteria were serially diluted and enumerated by spot plating on MRS agar to determine bacterial numbers. To determine the mid-exponential growth phase, the culture was monitored by measuring the absorbance at 600 nm (OD_{600 nm}) at intervals during growth.