which test for l monocytogenes is positive at 25oc and negative at 37oc 44944

Name: which test for l monocytogenes is positive at 25oc and negative at 37oc 44944
Uploaded: 2023-12-07T14:20:56-08:00
Duration: 4 min 52 s
Channel: Supreeta N
Description: which test for l monocytogenes is positive at 25oc and negative at 37oc 44944

Step 1: Identify the organism in question, which is Listeria monocytogenes, a bacterium that can

Which test for l monocytogenes is positive at 25oc and...

Transcript

00:01 Hello student here the question is given on the question having the phenol red broth and in this phenol red broth the turbidity absorbed and these turbidity observed after 48 hours so in this case it is kept in a slow -growing fermenter so this is added in slow -growing fermenter so if we are talking about these broth phenol red broth so this is the one which is the indicator of ph change because this is the lactose broth and this is the normally red in color and after changing this ph it become yellow so due to the presence of this inoculum or slow -growing fermenter there is the conversion of these lactose into the acid so this lactose is changes into the lactic acid so fermentation is going on so if the fermentation is going on then the color of this solution will change here the turbidity is absorbed after 48 hours so this is the slow -growing so the delay growth could here the delayed growth can be indicator of the false positive result because these is a slow -growing fermenter so the interpretation which we are taking is the conversion of this or the fermentation process going on it could be a false positive and this is mainly due to the poor sensitivity so this is mainly due to poor sensitivity or poor specificity and it is mainly not detecting the fermentation it could be it not detecting the fermentation because the fermenter is a slow -growing and it could give a false positive result and this is mainly due to the poor specificity as well as the sensitivity of these fermenter and due to this the slow growth of organism mainly these are the reason for these false positive result and if we are talking about the second question which are the catalase test so we know this catalase is the one which is involved in the breaking down of these hydrogen peroxide into the these water molecule and oxygen so these are formed by the catalase enzyme so if here a student added these hydrogen peroxide to the culture and after adding the student get distracted so due to the distraction because after adding these hydrogen peroxide into the culture these a production of oxygen is immediately and if he is distracted then he cannot observe these bubbles so if we distracted then cannot observe the oxygen bubble which release just after adding into the culture so it ultimately after some time if it come back then they can get the false negative results so he may think the reactions is not going on because he doesn't observe these bubbles and it's observed only just after adding these hydrogen peroxide into culture so it may interpret a false negative result so in both the cases the careful attention as well as the timing of interpretation is required in the case of these by microbiological experiment...

Question

Which test for L. monocytogenes is positive at 25oC and negative at 37oC?

Question

Which test for L. monocytogenes is positive at 25oC and negative at 37oC?

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