Kneifel W, Jaros D, Erhard F
Department of Dairy Research and Bacteriology, Agricultural University, Vienna, Austria.
Int J Food Microbiol. 1993 May;18(3):179-89. doi: 10.1016/0168-1605(93)90043-g.
Yogurts and yogurt-related milk products were produced using 44 commercially available starter cultures from 8 suppliers. The yogurt starters consisted of the classical yogurt microflora and the yogurt-related cultures containing Lactobacillus acidophilus and/or Bifidobacterium spp. instead of or in addition to the yogurt bacteria. The counts of lactobacilli in the fresh yogurts varied between 5.5 x 10(7) and 6.5 x 10(8) CFU/ml, and the counts of streptococci varied from 3.5 x 10(7) to 1.2 x 10(9) CFU/ml. About 80% of the yogurts had higher counts of cocci than rods. During storage of the products for 2 weeks at 6 degrees C the stability of the microflora differed markedly among the cultures. In the fresh yogurt-related products the L. acidophilus counts ranged from 4.0 x 10(5) to 2.6 x 10(8) CFU/ml; bifidobacteria were found at levels between 4.0 x 10(6) and 2.6 x 10(8) CFU/ml. In most products reduced viable counts of these bacteria were observed after 2 weeks. Titratable acidity increased on average by 22.3% in the yogurts, and by 14.9% in the yogurt-related products during storage. In most products a higher amount of L(+)- than D(-)-lactic acid was found.
酸奶及与酸奶相关的奶制品是使用来自8家供应商的44种市售发酵剂生产的。酸奶发酵剂由传统酸奶微生物菌群以及含有嗜酸乳杆菌和/或双歧杆菌属的与酸奶相关的培养物组成，这些培养物可替代酸奶细菌或在酸奶细菌之外添加。新鲜酸奶中乳酸杆菌的数量在5.5×10⁷至6.5×10⁸CFU/ml之间，链球菌的数量在3.5×10⁷至1.2×10⁹CFU/ml之间。约80%的酸奶球菌数量高于杆菌。产品在6℃下储存2周期间，不同培养物的微生物菌群稳定性差异显著。在新鲜的与酸奶相关的产品中，嗜酸乳杆菌数量在4.0×10⁵至2.6×10⁸CFU/ml之间；双歧杆菌数量在4.0×10⁶至2.6×10⁸CFU/ml之间。在大多数产品中，2周后观察到这些细菌的活菌数减少。储存期间，酸奶的可滴定酸度平均增加22.3%，与酸奶相关的产品平均增加14.9%。在大多数产品中，L(+)-乳酸的含量高于D(-)-乳酸。
