Meanings of sterile swab in English

So he looked the other way as Richard dabbed at a vein on his arm with a sterile swab.

I can roll the cotton up on wooden toothpicks and peddle them as sterile swabs.

Each cop, however, is accompanied by a worker in a lab coat holding a pouch of sterile swabs.

First they wiped sterile swabs on unchalked hands and then wiped the swabs on blood agar plates, which contain a growth medium for culturing microorganisms.