Proper streaking technique

Footage taken at a Senior-level Microbial Physiology Lab. This student is showing very good streaking technique for colony isolation. A good clip to show underclassmen whom are just being introduced to the technique.

Category:

Education

Tags:

• Microbiology
• bacteria
• lab
• agar
• plates
• streaking
• isolation
• colonies
• college
• biology
• university
• medicine
• physical
• science

[basramap]

@MulataLinda8 You have to flame the loop between each quad because your initial pick of bacteria is very highly concentrated. When you finish your first quadrant you've diluted out that initial pick of inoculum. Then you flame to kill everything on your loop. Then you begin the second quad diluting it out further. Then flame (or get a new sterile loop) to dilute out further, and after your incubation you'll see diluted/isolated colonies in your most dilute quadrant: quad 4 :)

[sp0rked]

What happened to sterilizing the loop/probe/prod between swipes?

Or does it matter at this point in isolation, since your trying to ISOLATE. it makes sense to clean your instrument between swipes... so you dont contaminate plate #3 with plate #2's transferred contents (assuming transfer with plate #1)

Or am I just doing it?

[hamzie11]

@tomoyo1chan1 thats for confluent growth

[kobald62]

@MulataLinda8 This streaking technique is for isolation so the goal is to thin out the bacteria as much as possible so that you can get individual colonies in the last quadrant of the plate. By flaming the loop between each section of streaks you can further minimize the amount of bacteria getting dragged over into the next quadrant. If you don't flame the loop you end up with big streaks of growth rather than individual colonies. Hope that helps...8 months later.

[tomoyo1chan1]

i thought u use a swab not that loop thing

[MulataLinda8]

why do u have to flame the loop between each quadrant?? I dunno if its because you are not under a hood, but we use sterile loops and do all quadrants with the same loop and if there are other plates we do those, too with the same loop., under a hood. dont get any contaminants

[ccfile]

How interesting! Which school is this?