in order to avoid the precipitation of casein during centrifugation. Afterwashing twice in sterile saline (0.85%,w/w), the cell pellets were ground on four
separate, consecutive occasions: beating for 20 s each at 3000 rpm with 0.1-mm zirconia silica beads in a Biospec mini bead-beater-16 after removing the beads and cell debris by centrifugation, the cell lysates were adjusted to 5 × 109 ruptured
S. thermophilus cells/g using distilled water according to the aforementioned S. thermophilus viable cell count.
then, lysates werefiltered through a 0.22-μm pore-size filter for sterilization. The obtained CCE was kept frozen (−80 °C) ready for use