Applied Microbiology and Molecular Biotechnology Research Group, Department of Molecular Biology and Genetics, Democritus University of Thrace, Alexandroupolis, 68100, Greece.
J Dairy Sci. 2013 May;96(5):3369-77. doi: 10.3168/jds.2012-6343. Epub 2013 Mar 15.
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.
本研究的目的是监测冷藏条件下普通酸奶中益生菌菌株干酪乳杆菌 ATCC 393 的存活率，与保加利亚乳杆菌相比。测试了在具有高工业应用价值的水果和燕麦片等载体上自由和固定化的细胞。微生物学和菌株特异性多重 PCR 分析表明，新型产品中可检测到游离和固定化的干酪乳杆菌 ATCC 393，其水平足以在 4°C 下冷藏期间（至少 30 天）发挥益生菌作用（至少 6 对数 cfu/g）。相比之下，保加利亚乳杆菌的活菌密度在冷藏 14 天后降至<6 对数 cfu/g。值得注意的是，所有产品的最终 pH 值均为 4.2 至 4.3。干酪乳杆菌 ATCC 393 的耐酸或耐冷性显然使其在这些酸奶配方中的存活率高于保加利亚乳杆菌。
