Police say an unidentified 14-year-old boy rode the bike at customers gathered at check-outs in the supermarket about 5.30pm (AEDT).
The customers in the Bachus Marsh supermarket, west of Melbourne, scrambled to escape the path of the bike.
The rider then slammed on the brakes leaving a 10-metre skid mark on the floor before hitting the automatic doors and breaking the glass.
Supermarket staff tried to detain the rider until a woman, who police believe was known to the teenager, arrived and verbally abused them.
Staff released the boy and he fled the store.
No customers were injured.
Police are still trying to identify the teenager.