After one week storage, all yoghurt samples were observed using
a CLSM Leica TCS SP5, equipped with an inverted DMI 6000 microscope
and multiple laser lines. A water objective of 63(N.A.1.2)
was used. Three fluorescent dyes were combined in each yoghurt
sample including the two lectin conjugates of Alexa Fluor® concanavalin
A 633 (ConA 633; Molecular Probes, Eugene, OR, USA) and
WGA 488, and rhodamine B (SigmaeAldrich, Munich, Germany). All
yoghurt samples were sequentially scanned by three laser lines
(Argon 488, HeeNe 543, and HeeNe 633). The lectin probes were
used to visualise EPS, and rhodamine Bwas used to stain the protein
gels of the yoghurts. The method essentially followed the procedure