came across an idea to investigate the bacteria in different types of milk.
ok, so maybe around 4 or 5 test tubes/glasses (depending on what i have access to) are gonna be filled with the same amount of water. a swab thing is supposed to be dipped in milk e.g. full cream milk; and then placed in the first glass of water. same thing done with another tube, except after it's dipped in the milk, it gets dipped in the first glass again and then in the second. the third time, the swab gets dipped in the milk, then the first glass, then the second, and finally in the third. same thing for the furth and fifth ones.
Then the swabs are placed on petri dishes (or another alternative) with this nutrient agar thing (google nutrient agar plates, they have a good definition of it). now, im not sure how to do this next part, but somehow the bacteria is counted? i still have to work on that.
The experiment is repeated for skim milk and soy milk. what do you think, good idea? or should i think of another one?
NOTE: my dad said this experiment may take up to 2 weeks, and im going overseas in the holidays, so i was thinking maybe compare soy milk from here and soy milk from india, and skim milk from here and skim milk from india and so on. should i do this or is it too much?
EDIT- it may take up to 3 weeks.
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Bacteria is counted by the colony, but usually you need to do a "serial dilution" to make sure that you can actaully count the bacteria (often there are too many to count!)
ReplyDeleteThe growth of bacteria should occur over 2 to 3 days- not 2 to 3 weeks.
Making the agar plates will be a pain in the butt, because you need to make sure that they are sterile- can you get them from another source?
The comparison between milk between here and India sounds good, but you realise that you can't actually bring in milk based products into Australia?
yeah, i do, i was thinking maybe compare home brand milk here and home brand indian milk, you know? but im not sure, it all depends on how long it takes. I'll research more on this serial dilution, and i was wondering whether you can buy agar plates and take them into other countries? or whether i should make them myself (or have someone else help)?
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