The first aim of this work was to compare the immunomodu-
latory properties of the bacteria currently used as dairy starters
after growth on milk or laboratory growth medium. The key point
was the removal of milk components, particularly milk caseins
organized as micelles, which would interfere with the human
PBMC used for the in vitro immunodulation test. For this purpose
we successfully applied a method to separate bacterial cells from
the skimmed milk components that might have intrinsic immune
properties (Beermann and Hartung, 2013). The bacterial cells were
washed with citrated water. This step led to solubilization of the
protein precipitates following the destabilization of the casein
micelles, which could easily be separated by centrifugation from
the bacterial cells. This was confirmed by microscopic control of the
absence of caseins micelles. According to this method, LAB and P. f
CB129 were tested individually for their immune properties after
cultivation in milk or laboratory growth medium. We observed
that, after growth in M17, the lactococcal CB 460 and CB 461 strains
presented anti-inflammatory properties measured by the IL-10
induction in PBMC to a higher degree than those measured in the
reference strain L. lactis MG 1363 (Fig. 1A). Therefore, induction of
IL-10 by distinct L. lactis strains grown on laboratory medium could
differ by a ratio of one to three, suggesting strain specificity, as