Tstl Ee Simon B S Pta

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Concernant la présentation orale.

La durée est un peu courte (4:34 mins au lieu de 5 mins)

Quelques erreurs Ă  Ă©viter comme : "20,000 twenty hundred =} twenty thousand, " to reach our problem which is" =} "to find our problem-question which is…", "future experience to be carried out" =} "future experiment to be carried out….", "ten power minus three" =} "ten to the power of minus three"

Attention Ă  la prononciation de certains mots comme "varieties", "balanced", "phytosanitary", "out", "put", "microbiological", "core",

N'oublie pas de bien prononcer le morphème –ed : "contained, "We then asked , "therefore allowed us to", "we therefore carried out", "this experiment allowed,

Il faut bien prononcer les "s" Ă  la 3ème personne du singulier et après chaque mot au pluriel, exemple "which are as follows, "The taste differs, "coventional apples,….

Attention Ă  la traduction de certains mots "serve as a mother solution for" =} initial suspension

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


1-The apple

The apple and the most cultivated fruit in France and is the 3rd most consumed fruit in the world. We know that the apple is composed of more than 70 million bacteria contained in the tail, the seeds and the calyx. There are 20,000 varieties of apples in the world divided into 5 families: the greedy, the scented, the balanced, the rustic and tonics. The most known and consumed variety is the Golden. The organic market has largely increased over the past ten years worldwide and is constantly increasing. We then asked ourselves: How is the organic apple microbiota different from the conventional apple microbiota? Is the yield of organic apples lower than conventional apples? We then met an arborist in our sector, from Saint Melaine sur Aubance, Jean Jaques PĂ©cot. He explained to us his trades, these controls, the phytosanitary products he used. This approach therefore allowed us to reach our problem which is: How does the processing of organic and conventional apples affect the conservation, taste and processing of apples?

2-The working hypotheses

After that we made several hypotheses to orient us towards future experience to be carried out. We have 4 hypotheses which are as follows:
• There is a difference in storage according to organic and conventional apples and an influence of their environment (room temperature, refrigerator).
• Processing influences the conservation of apples. (pesticides)
• The taste differs according to an organic or conventional apple.
• The microbiota differs in organic and conventional apples.

3-Choice of experiences:

Following the working hypotheses, we therefore carried out experiments to analyze and compare the microbiota of organic and conventional apples.

Experiment 1:

We put the apples in storage in different conditions. We put an organic and a conventional apple to keep in the refrigerator and an organic and conventional apple at room temperature and in the dark. This experience allowed us to compare the conservation difference between organic, conventional apples and their environment.

Experiment 2:


To begin with, we peeled 10 g of skin in a microbiological safety cabinet and take 10 g of the core using a sterile scalpel. We placed the 10 g of skin and 10 g of core in two different sterile bags by adding 90 mL of trypton salt broth. After closing these pockets we placed them in a stomacher for 180 seconds to make them out of the substrate. This substrate will then serve as a mother solution for inoculating the various media used. We diluted these stock solutions to 10-3 dilution. To carry out these dilutions so we had 9mL of stock solution in a sterile test tube and we transferred 0.1mL into a test tube containing 9mL of trypton salt to have a dilution of 1 / 10th. We repeated the experiment but this time not with the mother solution but with the diluted tube made just before to make the dilution tube 10-2 and the same for the dilution tube 10-3. We then seeded all the chosen media with the different solutions.

Experiment 3: for this experiment we will repeat experiment 2 using this time the apples put in conservation.


PCA: enumerates bacteria
M17: allows to isolate lactococci
CFC: allows to count the pseudomonas
VRBG: allows to count the coliforms (Enterobacteriaceae)

4-Results of the experiments:

Résultats expérience 2:


Résultats expérience 3:


Following these experiences we could see that conventional apples keep longer than organic apples whether in the fridge or at room temperature. We were also able to determine that organic apples were sweeter than conventional apples. And with the seeding we noticed differences between the microbiota of conventional apples and the microbiota of organic apples.

By comparing the results of Experiments 2 and 3 we could see that the organic apples left in the ambient air have more bacteria than before (skin: 136363 CFU / ml), which shows that the bacteria have grown while for conventional apples, leave less bacteria in the air than before (skin 4000 CFU / ml). For organic apples leave in the fridge the number of bacteria to decrease and went from 119,090 CFU / ml to 7272UFC / ml while for conventional apples leave in the fridge the number of bacteria also decreased but it only went from 36363UFC / ml has 14545UFC / ml which is much less. With these results we can therefore conclude that conventional apple processing allows better preservation of the microbiota of apples, whether in the fridge or in the air.

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