L'identification, le dénombrement et la survie des cultures probiotiques dans les yaourts bio commerciaux

Rapport de stage Sciences & technologies Biologie

Date de publication :

08/01/2009

Langue :

Anglais

Format :

.doc

Nombre de pages :

41 pages

Niveau :

expert

Consulté :

0 fois

Avis client :

non évalué

Validé par :

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Sommaire :

Sommaire

Material and methods
1. Microbial cultures in dairy products
2. Microbial cultures and their effects on health
3. Identification methods
4. Phenotypic techniques for the identification of probiotic bacteria available at the laboratory
5. Assessment of the media selectivity
6. Probiotic products
7. Study of the bio yoghurts microbial content
Results
1. Choice of selective media
2. Study of Actimel
3. Study of Tesco Probiotic
4. Study of Müller Vitality
5. Study of Onken Biopot
6. Study of Tesco Bio Yoghurt
7. Study of Spelga bio yoghurt
8. Study of the Loughry yoghurts
9. Confirmation with the other phenotypic methods
10. Other experiments

Résumé :

My work placement in Northern Ireland took place on Loughry Campus, which provides food education and training programmes for students who aspire to a career in the agri-food industry and also for postgraduate persons. In recent years, Loughry has developed a wide range of courses in Food Technology, Supply Management, Marketing and Packaging. The activities are not only educational. The food technologists and technicians are there to help companies to solve technical problems, develop new products or technologies and improve quality systems. The Food Incubation Centre and its eight food processing units is available for entrepreneurs wishing to establish food manufacturing operations or for existing food businesses wishing to develop, test and commercialize new concepts. The Packaging Centre, one of the most recent developments, provides a resource for evaluating packaging materials and distribution packaging systems.

I have worked in the microbiology laboratory, which has three main activities. The analysts carry out experiments on the products manufactured at Loughry. They also control products, which are being developed by companies. They also assist students like myself with their projects. That is why John Crawford suggested I conducted this project just like any other student of Loughry, by writing a research proposal in addition to this report. I also gave a presentation about the proposal and then about my results at the end of my stay.

My project involved the probiotic bacteria in bio yoghurt. Methods supposed to identify and enumerate these bacteria are numerous but controversial and do not give precise information on the microbial content of commercial products. The aims of this project were :
To find suitable selective media for bacteria involved in bio yoghurt manufacture
To ascertain the microbial content and count of commercially available products
To establish the survival of the microbial population of bio yoghurt when stored under domestic conditions

I also had the opportunity to take part in other activities such as product manufacture, workshops or taste panels, giving me experience in varied branches of the food industry. These activities took place at the Food Technology Centre, a 4 000 square metre hi-tech food technology centre.