Tstl Ee Coralia H S Pta

Pour écouter ma présentation orale =} Appuyez ici


Concernant la présentation orale.

La durée est trop longue (6:29 mins au lieu de 5 mins!),

Quelques erreurs à éviter : "one of the favourite fruits of the French" =} "of France", "between an organic apples apple and a conventional apple apples",

Attention à la prononciation de certains mots comme "rather", "such", "vitamins", "diabetes", "determine", "treated", "processed", "proceeded", "microorganisms", "acidic "

Il faut bien prononcer les "s" à la 3ème personne du singulier et après chaque mot au pluriel, par exemple "26 days"

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


The organic market has grown significantly in recent years, especially for fruit and vegetables. My team and I found this subject rather interesting. The apple is the most consumed and grown fruit in France and third in the world. In spite of the strong recommendations of the organic sector, certain questions were on our minds. Do the preservation, taste and components … of organic products, such as apples, differ from conventional products ?


I- Study of the microbiota of organic and conventional apples

As said before, the apple is one of the favourite fruits of the French, which is a good thing. In addition to being rich in fibre, pectin, vitamins and antioxidants, helping to lower cholesterol levels, regulating transit, fighting diabetes, reducing the risk of obesity and preventing muscle loss, the apple contains millions of bacteria that are excellent for our intestinal system, allowing good regulation of digestive, metabolic, immune and neurological functions and reducing the risk of infection and inflammation.

We therefore chose to compare the difference between the microbiota of organic and conventional apples in two different parts of the fruit (skin and core).

To carry out this experiment we chose specific nutrient identification media
to determine a difference in microbiota between the two types of apples.


- PCA: all microorganisms; total flora

- M17: Lactococcus

- CFC: Pseudomonas

- SRM: Lactobacillus

- SABOURAUD: saprophytic or pathogenic yeasts and moulds.

- BAIRD-PARKER: Staphylococcus aureus


When reading the identification agars, we found that the organic apple contained a greater number of microorganisms and its microbiota was more diverse than that of the conventional apple.


  • Fungicides: to fight against fungus
  •  Insecticides: to repel insects and pests that attack crops
  •  Herbicides: for crop weed control
  •  Growth regulators

Unlike conventional apples, organic apples are processed with natural products.

It is said that pesticides are used to protect agricultural crops against various threats, in order to limit the risk of crop loss. Some plant protection products are used to improve the shelf life of fruits and vegetables.

To be able to observe a difference in preservation, between an organic apple and a conventional apple, we placed apples in two different incubation media for several days in the dark :
(Note: at the beginning of the experiment, the apples had been harvested a few days before).

• At room temperature
• In a refrigerator


26 days after the experiment began, the organic apples were a little withered but they were still all edible.

After 32 days of incubation we noticed that apples at room temperature had a better shelf life than apples put in the refrigerator. The organic apple that had been placed in the refrigerator was very damaged and was beginning to rot.

The pesticides contained in the apples therefore promote a shelf life of about one to two weeks. Limiting or even using natural products would therefore be feasible for farmers.

III - Does the acidity of organic or conventional apples differ?

We know that acidity plays in favour of the taste of our food. The purpose of this experiment is to compare the acidity between an organic and a conventional apple juice.

We therefore proceeded to a dosage of this acidity.


The volume at equivalent dosages of organic apple juice was less than that of conventional juice (an average difference of 3.4 mL).

Veq organic juice 1 = 16.85 mL


Veq organic juice 2 = 16.9 mL
Veq juice conv 1 = 13.6 mL
Veq juice conv 2 = 13.4 mL

Organic apples are therefore less acidic than conventional apples.


We have therefore managed to answer the initial problem.
• The organic apple contains a greater number of microorganisms and its microbiota was more diversified than that
of the conventional apple.
• Conventional apples have a better shelf life than organic apples, but there is not much difference.
• Organic apples are less acidic than conventional apples.

Organic products therefore differ from conventional products, they are healthier, taste better and have almost the same shelf life. It's time to go organic!

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