Lactic acid bacteria(LAB) strains producing β-galactosidases with high transgalactosylation activity were screened from 148 LAB strains found in 13 kinds of traditional Chinese fermented foods. The strain 70810 produced β-galactosidases with the highest transgalactosylation activity and was isolated using a 5-bromo-4-chloro-3-indolyl β-D-galactopyranoside(X-Gal) plate for the primary screening, thin layer chromatography(TLC) for the secondary screening, and gas chromatography(GC) for quantitation. Lactose w...