title: Monitoring survival of Lactobacillus casei ATCC 393 in probiotic yogurts using an efficient molecular tool.
abstract: The aim of the present study was to monitor the survival of the probiotic strain Lactobacillus casei ATCC 393 during refrigerated storage of natural regular yogurts compared with Lactobacillus delbrueckii ssp. bulgaricus. Both free and immobilized cells on supports of high industrial interest, such as fruits and oat pieces, were tested. Microbiological and strain-specific multiplex PCR analysis showed that both free and immobilized Lb. casei ATCC 393 were detected in the novel products at levels required to confer a probiotic effect (at least 6 log cfu/g) for longer periods than required by the dairy industry (≥ 30 d) during storage at 4°C. In contrast, the viable bacterial density of Lb. delbrueckii ssp. bulgaricus decreased to levels <6 log cfu/g after 14 d of cold storage. Of note, the final pH of all products was 4.2 to 4.3. Acid resistance or cold tolerance of Lb. casei ATCC 393 apparently allows for increased survival compared with Lb. delbrueckii ssp. bulgaricus in these yogurt formulations.
authors.affiliation: Applied Microbiology and Molecular Biotechnology Research Group, Department of Molecular Biology and Genetics, Democritus University of Thrace, Alexandroupolis, 68100, Greece.
authors.forename: Marianthi
authors.initials: M
authors.lastname: Sidira
authors.forename: Georgia
authors.initials: G
authors.lastname: Saxami
authors.forename: Dimitra
authors.initials: D
authors.lastname: Dimitrellou
authors.forename: Valentini
authors.initials: V
authors.lastname: Santarmaki
authors.forename: Alex
authors.initials: A
authors.lastname: Galanis
authors.forename: Yiannis
authors.initials: Y
authors.lastname: Kourkoutas
mesh_terms: D061353:Food Storage; D006863:Hydrogen-Ion Concentration; D007780:Lacticaseibacillus casei / Q000502:physiology*; D048668:Lactobacillus delbrueckii / Q000502:physiology; D060885:Multiplex Polymerase Chain Reaction / Q000379:methods; D019936:Probiotics / Q000592:standards; D013997:Time Factors; D015014:Yogurt / Q000382:microbiology* / Q000592:standards