The DU Lounge

It probably won't refreeze right - there will be ice crystals formed from the atmospheric moisture that is adsorbed by ice cream when melting at room tempertures. Most ice cream has a specific freezing protocol (with controls and conditions to optimize it) that creates the texture and smoothness that re-frozen won't have...

But from a microbioloical perspective, until the material gets fully thawed and bacteria start to colonize and grow in it (usually not duing the thaw, but not impossibe either) you would not be at significant risk to try refreezing and eating it. The re-freeze would kill some bacteria and halt the growth of others.

Smell test is not foolproof but better than nothing - if it smells bad (sour milk-y) throw it out. If you don't mind ice crystals and a lack of smoothness, go for it.... Good luck!