  We show that quasiparticle interference (QPI) due to omnipresent weak
impurities and probed by Fourier transform scanning tunneling microscopy and
spectroscopy acts as a direct experimental probe of bulk odd-frequency
superconducting pairing. Taking the example of a conventional $s$-wave
superconductor under applied magnetic field, we show that the nature of the QPI
peaks can only be characterized by including the odd-frequency pairing
correlations generated in this system. In particular, we identify that the
defining feature of odd-frequency pairing gives rise to a bias asymmetry in the
QPI, present generically in materials with odd-frequency pairing irrespective
of its origin.
