  We demonstrate the preservation of time-energy entanglement of near-IR
photons through thick biological media ($\leq$1.55 mm) and tissue ($\leq$ 235
$\mu$m) at room temperature. Using a Franson-type interferometer, we
demonstrate interferometric contrast of over 0.9 in skim milk, 2% milk, and
chicken tissue. This work supports the many proposed opportunities for
nonclassical light in biological imaging and analyses from sub-shot noise
measurements to entanglement-enhanced fluorescence imaging, clearly indicating
that the entanglement characteristics of photons can be maintained even after
propagation through thick, turbid biological samples.
