Study of Survival During Drying of Bacterial Cells of Starter Culture for Probiotic Fermented Milk Drinks

Abstract

Five proprietary variants of bacterial starter culture with the following species composition were studied: No. 1 – Lac. diacetilactis, Lac. cremoris, Lac. acidophilus, No. 2 – Lb. plantarum, B. adolescentis, No. 3 – Lac. cremoris, No. 4 – Lac. lactis, Lac. diacetilactis, Lb. plantarum, No. 5 – Lac. lactis, Lac. diacetilactis, Lb. cremoris. Survival was assessed immediately after freeze-drying and during storage after 30, 90 and 180 days. It was found that the lactococci included in the bacterial starter culture of variants No. 1, 3-5 after drying and during storage showed the maximum survival of bacterial cells. Their number varied within the limits: after drying – 3.3-6.5 × 109 CFU/g, after 180 days – 1.0-2.0 × 109 CFU/g. A high degree of survival was noted in L. acidophilus (variant No. 1) – the number of viable cells after drying, as well as after 180 days of storage at the level of 1.0×108 CFU/g. The total amount of probiotic microflora of Lb. plantarum and B. adolescentis bacterial starter culture (variant No. 2) after drying was 3.2×109 CFU/g, and after 180 days of storage 1.0×109 CFU/g. Both cultures showed high survival of bacterial cells. The number of Lb. plantarum (variant No. 4) after drying and during storage was only 1.0×106 CFU / g, but it should be taken into account that this culture in the starter composition is additional, while the dominant microflora is represented by lactococci.