Identifiying Bacteria colonies

[SlayerSlays]

I did a science project for my science fair (of course) and I got the idea from one of your experiments. I tested which company of yogurt has the most bacteria. I used Activia Danone and Yoplait Source. I have kept them in a bacteria incubator for 6 days so far,and have noticed 3 big colonies of bacteria in the Activia Danone and any small (I think) colonies in the Yoplait Source.I would really like to identify them maybe to earn some extra points. My science teacher advised me to do so and said to get in contact with a expert. I don't know if any of you are expert in this domain but I you should be one, well what I can say about the morphology is that in the Danone Activia there is one colonie that is bigger than the other so let me start with that one. I has a light beige colour, it's in a shape of a circle and I'd say about a couple millimeters in length. The second largest (in length) is of a pale yellow colour a shape of a circle and probably 2 millimeters in length. Now for the final one, it's colour the same colour as the first one but a bit darker, it's in shape of a circle and might be even 1 millimeter. Sorry if I can't get the exact mesurments it's just that the plats have already been thrown away and I'm basing off of pictures I have taken. Now in the Yoplait Source there are many little dots in the shape of water dropplets falling off of the windscreen of a car, but that little line they leave behind. They are all of the same colour white and less than a millimeter in length. (Some are in that shape that I described and some are just dots.) For the agar plates I'm not too sure which one type of agar was used I'd need to check in on my science teacher. So I will get back to you as soon as I can with that information. I did change the experience as in I used a proper bacteria incubator and I can't seem to find other things that I find important. Thank you so much for your help, it's very much appreciated !

-Slayer

[allisontu]

Hi Slayer,

It can be very difficult to identify bacteria just based off of appearance. However, since you were culturing yogurt, you may be able to identify these colonies.

Yogurt usually contains lactobacillus and bifidobacterium, two strains of helpful bacteria. These, and several other "good bacteria" help the milk ferment, turning it into yogurt. These types of bacteria are probably the ones present on your agar plates. Here's a link with more information about the bacteria.
http://www.livestrong.com/article/34906 ... in-yogurt/
You can look up photos of colonies of these types of bacteria and compare them to the appearance of your plates.

However, to be sure about the type of bacteria present, you'd have to conduct more testing. You may want to conduct a local microbiologist and ask them if they'd be willing to help you identify the bacteria.

Hope this helps,
Allison