During the anti bacterial treatment, the socks are dipped in a water
bath containing the anti bacterial chemical component. Once a sock
is treated this way, bacteria won’t be able to grow or proliferate in this fabric.

Depending on the chemicals used, the socks will stay free of bacteria over 10-50 washes.

Given that bacteria are responsible
for the sometimes not so pleasant odour of socks, you literally can’t
see nor smell antibacterial treatment.