Bacterial Plating | Streak Plate Method | PraxiLabs

Bacterial Plating Out Technique Experiment (streak plate method) Virtual Lab

Biology | Molecular Biology | Biochemistry | Genetics | Microbiology

As Featured In

General Aim

The plating out technique is used for the isolation of bacteria into a pure culture of the organisms from a mixed population.


Streak plate Method.

Learning Objectives (ILO’s)

  • Become proficient at performing streak plate method consistently and accurately.

  • Produce isolated colonies of an organism on an agar plate.

  • Identify the organism: biochemical tests to identify bacteria are only valid when performed on pure cultures.

Theoretical Background/Context


  • In microbiology, streaking is a technique used to isolate a pure strain from a single species of microorganism, often bacteria.
  • The dilution or isolation by streaking method was first developed by Loeffler and Gaffky in Koch’s laboratory, which involves the dilution of bacteria by systematically streaking them over the exterior of the agar in a Petri dish to obtain isolated colonies which will then grow into the number of cells or isolated colonies.
  • Streaking is rapid and ideally a simple process of isolation dilution.
  • The technique is done by diluting a comparatively large concentration of bacteria to a smaller concentration.
  • The decrease of bacteria should show that colonies are sufficiently spread apart to effect the separation of the different types of microbes.
  • Streaking is done using a sterile tool, such as a cotton swab or commonly an inoculation loop.
  • Aseptic techniques are used to maintain microbiological cultures and to prevent contamination of the growth medium.

Principle of Work

The streak plate method is a rapid qualitative isolation method.
It is essentially a dilution technique that involves spreading a loopful of culture over the surface of an agar plate.
The resulting diminution of the population size ensures that, following inoculation, individual cells will be sufficiently far apart on the surface of the agar medium to effect a separation of the different species present.
The streaking process will dilute out the sample that was placed in the initial region of the agar surface.

PraxiLabs is Recognized Worldwide

Customers Love PraxiLabs

“With the onset of the COVID-19 pandemic, we found ourselves in a situation that forced us to act quickly to find the best solution available to provide our students with a quality molecular genetics laboratory experience.”

Korri Thorlacius, B.Sc.
Biology Laboratory Instructor
Biology Department
Kwantlen Polytechnic University

'' Although there are now several vendors offering virtual reality software for physics labs, there is only one that offers a realistic, I feel like I’m in a real lab, solution: PraxiLabs.''

Dr.‌ ‌William‌ ‌H.‌ ‌Miner,‌ ‌Jr.‌ ‌
Professor‌ ‌of‌ ‌Physics‌ ‌
Palm‌ ‌Beach‌ ‌State‌ ‌College‌ ‌
Boca‌ ‌Raton,‌ ‌FL‌

" PraxiLabs offered my students a chance to actively engage with the material. Instead of watching videos on a topic, they could virtually complete labs and realize the practical applications of class topics. This is a quality alternative to in-person labs."

Crys Wright
Teaching Assistant
Texas A&M University, USA

"Great user experience and impressive interaction, I am very pleased to have tried the simulations and will continue to do so."

Dr. Khaled M Goher
Lecturer in Biomedical Engineering
Aston University, UK

The #1 Science Virtual Labs used by Educational Institutions

Explore More Interactive 3D Virtual Simulations

Designed for Safety and Engagement

Find out how PraxiLabs keeps students engaged and improves learning outcomes