Milk Microbiology - (Dec/06/2011 )

Hello
I have a packet of milk (Sealed polythene by Company) which had to expire in 3-4 days but now it is 6-7 weeks old. It is still in my refrigerator and separate liquid and clumps appearing in it.
what experiment do you suggest me with this, in relevance to isolate different microorganisms?

Thanks..

just plate out some of the milk or inoculate some broth..

Not sure what you are trying to do really..

You simply want to find out what microbes are common in milk?

Anyway, there are papers out there describing what kind of microbes are common in milk products, so based on that you can allready select certain types of agar.
However, I would also inoculate the more general agars to see if something weird pops up.

Is it for students? or?

Hello Pito
this is not for students, and I want to know what microorganisms can be there in spoiled milk. it is more than 6 week old and I Expect some different than normal microflora. so just wanted a suggestion from others before opening it.
so main question is how to utilize this for microbiology..
I can make dilutions..
media I have are Nutrient agar, Actinomycetes Isolation agar, YPD....

microbes on Thu Dec 8 17:23:33 2011 said:

Well, I would start with reading some literature concering milkbacteria and food spoilage...
(perhaps you need to check your national health regulation.. normally they have lists with bacteria most common found in dietary/milk proucts gone bad..)
I would aslo plate out some dilutions on simple nutrient agar because, like you said, you might find some bacteria you dont expect..
But think about milk gone bad and what you taste/smell then at first... the sourness.. and what causes this...

Not sure why Actinomycetes Isolation Agar but as always pito made some good points. Consider the bacteria one would find in soured milk and the media necessary for theirfrecovery/ isolation. Sour milk would probably be acidic in pH so maybe Lactobacillus agar.

If the pouch was never oopened, the diference from fresh would be in numbers not types of bacteria.