Practical points that keep a microbiology project both safe and approvable.
Use known cultures. Order a characterised, non-pathogenic strain from an educational supplier rather than culturing an unknown from the environment. You know what you are growing, and the paperwork is far simpler.
Sterile technique. Flame or use disposable loops, work near a flame or in a still-air box, open plates as briefly as possible, and never leave a plate open on the bench.
Seal plates after inoculation with tape and do not reopen them. All observation is through the lid.
Incubate below body temperature. Around 25–30 °C selects against organisms that grow well in humans. Never incubate at 37 °C in a school setting.
Plan disposal first. Autoclave at 121 °C for 20 minutes, or soak in fresh 10% bleach for 20 minutes if no autoclave is available. Write the disposal method into your protocol before you start — a reviewer will look for it.
Record everything. Strain, source, medium, incubation temperature and duration, and disposal date and method, for every plate.