In regards to the role of extracellular S. thermophilus molecules, no
statistically significant differences (p N 0.05) in the acidification performance
were observed following the addition of either native or heated
CFS, at a final concentration of 0.02–2.0% (w/w) in 12% RSM compared to
the untreated control cultures (data not shown). These results are
consistent with Vinderola et al. (2002), who also found that the CFS
obtained from skim milk cultures fermented by S. thermophilus had no
positive effect on probiotic L. casei.