The purpose of this practical is to investigate the effect of antiseptics or antibiotics on bacterial growth using agar plates and measuring zones of inhibition. This allows the selected bacteria ...

It is therefore important that any petri dish or agar used is sterilised before use, and that aseptic techniques are used to inoculate the plates. An inoculating loop can be used to transfer bacteria.

The cases all pointed to the same suspect: agar. Agar is and has been a staple of microbiology labs for a century. “We buy it in bulk. We buy kilograms at a time,” Protacio told me.