The growth-promoting properties of CFS and CCE isolated from
S. thermophilus on L. casei LC2W were determined by evaluating the
acidification performance and L. casei cell viability. 
Different concentrations of heated (sterilized at 110 °C for 15 min) or native (sterilized using afilter) 
CFS and CCE were added to sterile RSM (final concentration of RSM, 12%, w/w) to prepare the media. The CFS- and CCE-supplemented media were then inoculated with L. casei LC2W
(1 × 107 CFU/g) and incubated at 37 °C. 
RSM without supplementation was inoculated with L. casei LC2W as a control. The pH of each culture was measured with a 420A pH-meter and the viable cells were counted using MRS agar every 24 h.