I would like to know how to classify the bacteria found
in yogurt. I know most of their names, I just don't know what they are
supposed to look like.
Can you Help me?
Cultures (not the blended kind). I have my students gram stain a small bit
of the yogurt to see that there are actually living bacteria in it. The
bacteria we see are Gram positive (purple) and are cocci (round) in chains (
Streptococcus lactis) and bacilli (rods) in chains or singles (Lactobacillus
sp.) These are bacteria that use lactose (milk sugar) for their energy
source. The acids they produce as end products of their metabolism (waste)
curdle the milk protein and also give the sour taste to the yogurt.
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Update: June 2012