  We calculate the strange quark content of the nucleon directly from its
disconnected three-point function in N_f=2+1 QCD. Chiral symmetry is crucial to
avoid a possibly large contamination due to operator mixing, and is exactly
preserved by employing the overlap quark action. We also use the all-to-all
quark propagator and the low-mode averaging technique in order to accurately
calculate the relevant nucleon correlator. Our preliminary result extrapolated
to the physical point is f_{T_s} = 0.013(12)(16). This is in good agreement
with our previous estimate in N_f=2 QCD as well as those from our indirect
calculations using the Feynman-Hellmann theorem.
