Tstl Sarah D S Pta

Pour écouter ma présentation orale =} Appuyez ici

et pour visualiser mon diaporama =} Appuyez ici




Concernant la présentation orale.

La durée est parfaite (5:24 mins),

"was keep"— =} "was kept" …c'est au passĂ©, donc il faut utiliser le prĂ©tĂ©rit.

Attention Ă  la prononciation de certains mots "transparents" comme ""consequence", microorganisms", "analyse" et Ă  la traduction de certains termes comme "un blanc" =} control sample

Il faut bien prononcer les "s" Ă  la 3ème personne du singulier et après chaque mot au pluriel, exemple "different forms, "colonies, ….

N'oublie pas de bien prononcer le morphème –ed : "worked", "asked", "discovered",

C'est bien présenté et ton texte est bien écrit.

- Hello today I will present you our project on powder of cocoa-

First, here is the summary:
First, I will explain to you the research and asking that I made to find a problem question.
Then I will tell you what our problem question is.
So, I will present to you the instructions of experiments that I did with their respective results.
But I met problem, I will tell you which are.
To finish I will conclude

To find our problem question we did some research on cocoa, and we found the best ways to preserve cocoa powder. Cocoa exists in different forms, in powder, butter, chocolate bars. We decided to work on cocoa powder. We worked on two cocoa powder, one that was out of date in 2015 and the other that is out of date in 2021. The 2015 was kept in a cardboard box in its original packaging, by 2021 also. We came to ask ourselves a question, is that cocoa perishes.

problem question:
So we asked the question, What are the consequences if we do not respect the storage conditions, ideally provided for cocoa powder?


we did different experiments, we started by doing a enumeration to see if there were microorganisms. For the enumeration we could not deduce anything from it because during the testing session there was a lot of passage which took away contaminants on the boxes
We made a gram staining to see if we have some bacteria in the powder, so here is the step of the gram staining:
1-Light the Bunsen burner
1(bis)- Sterilise the inoculation loop
2- Take some colonies isolated on agar medium and make a suspension (in physiological water)
3- Make a bacteriological smear on the slide with the inoculation loop
4- Let the preparation dry and fix it with the flame of the Bunsen burner
1- Put the slide on the crystal violet during -> 1 minute
2- Inhibit the slide with the lugol’s iodine solution during -> 1 minute
3- Wash the slide quickly with ethanol and wash with distilled water
4- Put the slide on the safranin during -> 1 minute
5- Wash one last time with distilled water and dry/absorb it with filter paper.
6-Adjust the microscope + put an oil drop on the sample
After we have observed the Gram under a microscope, we can analyze the results. We cannot deduce anything from this, because the staining of the Gram took the particles from the cocoa powder .


we did the flag technique and isolation to see if something was developing, but we got nothing. Isolation:


We also made a range:


problems :

We encountered problems with the enumeration and the Gram, with the enumeration we saw nothing because there were contaminants, if there had been something it would have been in the mass and for the Gram as I said, the cocoa particles absorb the colorations.


To conclude, following our results we observed that there is no difference between the two cocoa powder . So no matter in which container the cocoa is keeping it does not affect the consumption, and thanks to this we discovered that at least up to 5 years, the cocoa does not perish and it can be consumed

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