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Name: Danielle
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I have to do a science fair project. What I need to compare the relative bacterial levels in milk samples with different expiration dates. What can I use to test the bacteria? Please help!

You want to see if there are bacteria present in milk of different expiration dates, and if so, what they do to the milk. So buy milk of different dates. You could test what effect storage temperature has on bacterial growth in milk. Use those different milk samples in their original package (don't open it!) and keep them at 37 degrees C, at room temperature, and in the fridge (measure how cold that is) for say 48 hrs.Then open the bottle or pack and see what happened to the milk. Do you see differences? Can you explain them? If you open the milk before the experiment you may get bacteria into the milk that otherwise would not have been there. The experiment with the closed bottles will tell you what is better, storage of milk at room temperature, warm, or cold.

Good luck!
Trudy wassenaar

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