The general objective of this project is to provide more information on bacterial strains to be used as probiotic additives to fermented milk; standardized characterization tests, specifically developed by the participants to the project, will be used to assess the so called probiotic effects of lactobacilli and bifidobacteria.
The lack of standardized procedures to assay probiotic properties has impaired the possibility of gaining a more deep knowledge on this matter and restricts comparison of data reported by the available literature.
Research was carried out to provide more information on bacterial strains to be used as probiotic additives to fermented milk; standardized characterization tests developed will be used to assess the so called probiotic effects of lactobacilli and bifidobacteria.
creation of Project Culture Collection (PCC), containing about 100 strains of enteric isolates of lactobacilli and bifisobacteria, as well as a limited number of strains of nonenteric origin;
characterization of these strains, by means of assay procedures that have been developed and standardized (characters under investigations are drug resistance, antagonistic properties, acid resistance, bile salt metabolism, cholesterol metabolism, growth requirements, intestinal tract adaptation and colonization ability of intestinal tissue).
Strains selected for the PCC were assayed for acid and bile salts resistance resulting in the development of a standardized method to assay bile salts resistance in lactic acid bacteria.
An investigation into the different results obtained from bovine or porcine bile salts has been carried out and work has proceeded on tests performed on solid media which shown to be more reliable than those performed using broth cultures. It was also possible to find enteric isolates of lactic acid bacteria which do not tolerate very low concentrations of bile salts. The method developed to test susceptibility of strains to acid shock was found suitable to detect isolates with high resistance towards acid.
2 databases are available, both in MINE format; the first one was developed using DB3 software, the second using ORACLE (which can use also the DB3 stored data).
Classification of freshly isolated strains is in progress, using standard tests and molec ular taxonomy. Specific deoxyribonucleic acid (DNA) sequences, based on 16S and 24S ribonucleic acid (RNA) sequencing will be synthesized and used as probes.
The health promoting qualities of probiotic products (i.e. fermented milks added with enteric lactic acid bacteria) remains an issue of debate among the scientific world. The lack of standardized procedures to assay probiotic properties has impaired the possibility to gain a deeper knowledge on this matter and to compare data reported by the available literature.
Moreover, even if a large number of papers focused on 'probiotic products', was recently published, most of them deal with different strains and the amount of data available on each single 'probiotic' strain is scarce.
Participants will study a defined group of strains, common to all the labs involved in the project, in order to be able to compare data obtained using the standardized procedures.
Funding SchemeCSC - Cost-sharing contracts
6710 BA Ede