Galactose positive S. thermophilus strains are
technologically important, since they can inhibit the growth of
undesirable lactic acid bacteria, and prevent the browning defects
(Giraffa et al., 2001). Additionally, they have often been the targets
for metabolic engineering studies for enhancing the exopolysaccharide
(EPS) biosynthesis (Levander, Svensson, & Radström,
2002). Several explanations were proposed for Gal (þ) phenotype
in the literature.