Microbiological, physico-chemical, nutritional and sensory characterization of traditional Matsoni: selection and use of autochthonous multiple strain cultures to extend its shelf-life.

Matsoni, a traditional Georgian fermented milk, has variable quality and stability besides a short shelf-life (72-120 h at 6 °C) due to inadequate production and storage conditions. To individuate its typical traits as well as select and exploit autochthonous starter cultures to standardize its overall quality without altering its typicality, we carried out a thorough physico-chemical, sensorial and microbial characterization of traditional Matsoni. A polyphasic approach, including a culture-independent (PCR-DGGE) and two PCR culture-dependent methods, was employed to study the ecology of Matsoni. Overall, the microbial ecosystem of Matsoni resulted largely dominated by Streptococcus (S.) thermophilus and Lactobacillus (Lb.) delbrueckii subsp. bulgaricus. High loads of other lactic acid bacteria species, including Lb. helveticus, Lb. paracasei and Leuconostoc (Leuc.) lactis were found to occur as well. A selected autochthonous multiple strain culture (AMSC) composed of one Lb. bulgaricus, one Lb. paracasei and one S. thermophilus strain, applied for the pilot-scale production of traditional Matsoni, resulted the best in terms of enhanced shelf-life (one month), sensorial and nutritional quality without altering its overall typical quality. This AMSC is at disposal of SMEs who need to exploit and standardize the overall quality of this traditional fermented milk, preserving its typicality.