Protection of natural starter cultures for traditional dairy production against phage attack

Traditionally, many of the fermented foods are produced under spontaneous fermentation using back-sloping method, which involves direct addition of predominant native lactic acid bacteria as selected starter culture. This approach participate to protect fermentation by spoiling agents.
Maintenance and viability of starter culture is still an issue in the industrial process. The fermentation can be impaired by virulent bacteriophages (phages): if the same starter culture is repeatedly inoculated, (e.g. by back-sloping), specific virulent phages could emerge, killing the added starter cultures and adversely affect the fermentation process. This is frequent during dairy fermentation of traditional raw milk products. It has been shown that encapsulation of starter culture could provide many advantages compared to traditional starter bacteria cultivations, in particular enhanced tolerance of the bacteria towards environmental stresses like high temperatures, low pH and phage presence.

1) Screening of Lactic acid bacteria strains isolated from local traditional dairy environment for their technological performance as starter and non-starter bacteria 
2) Screening of phage presence along the dairy supply chain
3) Whole genome sequencing of the bacteria to test their safety and the possibilities of their use in natural starter cultures. 
4) Test of the bacteria viability, release and activity in vitro after fermentation of medium by microcapsules obtained from different materials of encapsulation/coating of bacteria.
5) Test of the robustness and efficiency of the different micro-encapsulated dairy starter for the protection of natural starter cultures against different titres of dairy phages 
6) Analysis of experimental model of traditional cheeses produced by means of natural starter cultures obtained with micro-encapsulated bacteria. The model of traditional cheeses will be analyzed for shelf-life, viability of the starter bacteria and starter bacteria activity.

1. Determination of the microbiota of local traditional dairy products and the presence of putative source of phage attack during fermentation 
2. Estimation of the performance of autochthonous lactic acid bacteria (LAB) as starter to be used in traditional dairy production.
3. Bio-bank building with autochthonous performing LAB to be used in enriching local natural starter biodiversity’s.
4. Set up of a protocol for the use of different cocktails of starter bacteria for the constitution of natural starter cultures. 
5. Validation of a new preservation strategy against phage attack in natural starter cultures used for traditional dairy production.