the cells were harvested (13,400 g for 15 min at 4 C) by centrifugation (Eppendorf 5417R refrigerated centrifuge, Eppendorf, Milan, Italy), washed twice, and re-suspended with sterile Ringer solution (Oxoid) to give a similar final concentration. Bacterial suspensions were gradually distributed into the batter during mixing to achieve a uniform distribution of the inoculum and a final concentration ca. 104e105 CFU/g.