Culturing Microorganisms

• the agar gel plates contain nutrient broth which is what the bacteria need to grow and divide
• sterilise all petri dishes - kills any unwanted microorganisms
• sterilise the inoculating loop - pass it through a bunsen burner flame
• attach lid with adhesive tape - stops lid from falling off and unwanted organisms entering
• place agar plate in incubator upside down - stops moisture dripping onto bacteria
• incubate at 25 degrees - reduces chance of harmful bacteria growing
• 1

  clean surface with disinfectant - kills microorganisms that could contaminate
• 2

  sterilise inoculating loop with flame
• 3

  open sterile agar plate near bunsen burner - flame kills bacteria in air
• 4

  use loop to spread chosen bacteria evenly over the agar plate
• 5

  place sterile filter paper containing the antibiotics onto the plate then incubate at 25 degrees
• zone of inhibition


  where bacteria hasn’t grown around the antibiotic