  It is argued that it is valid to use QCD sum rules to determine the scalar
and pseudoscalar two-point functions at zero momentum, which in turn determine
the ratio of the strange to non-strange quark condensates $R_{su} =
\frac{<\bar{s} s>}{<\bar{q} q>}$ with ($q=u,d$). This is done in the framework
of a new set of QCD Finite Energy Sum Rules (FESR) that involve as integration
kernel a second degree polynomial, tuned to reduce considerably the systematic
uncertainties in the hadronic spectral functions. As a result, the parameters
limiting the precision of this determination are $\Lambda_{QCD}$, and to a
major extent the strange quark mass. From the positivity of $R_{su}$ there
follows an upper bound on the latter: $\bar{m_{s}} (2 {GeV}) \leq 121 (105)
{MeV}$, for $\Lambda_{QCD} = 330 (420) {MeV} .$
