5 Choose the true statements about the lactose in EMB agar...

5 Choose the true statements about the lactose in EMB agar (select all that apply). a. Lactose fermenters may appear pink. b. Lactose fermenters may appear dark green/blackish. c. Most coliforms can ferment lactose. d. EMB agar only allows us to assess lactose fermentation ability for Gram-positive bacteria. e. Bacteria will only grow on EMB agar if they can use lactose as a carbon source.

Transcript

0:00 Hello students.

00:01 Now in this question, they've given that in a culture plate, wherein the media is emb media, they saw that there were colonies that were produced.

00:12 And these colonies, as you can see, are light pink in color.

00:17 Now, what does that tell you about the organism that has grown on the culture plate here? is it gram positive? can it ferment man at all? is it a halophile? can it not? ferment the lactose, is it gram negative or it cannot ferment the glucose.

00:35 Now to know that, first let us understand about this emb media.

00:40 What is emb media? it is nothing but eosin, methyline, blue agar, right? e stands for eosin, m stands for methyline and b stands for blue agar, right? so in this case, you're adding this media.

00:59 What is the significance? of this media? basically, it is a selective media that helps in selecting the gram negative bacteria.

01:10 Now, what is so special in this that it only selects the gram negative bacteria? the eosin that is present is toxic to the gram positive bacteria as a result of which only gram negative bacteria can survive on this media and they can grow as well.

01:29 So here we know one thing for sure that in the cmb media other than gram negative bacteria, nothing else can grow.

01:38 Now, coming to the color that is being provided, they have told that there is pink color that is present, right? in this pink color, what you're observing that too light pink, it is not just dark pink, it is the light pink...

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