酸奶，由德氏乳桿菌亞種，乳酸菌和鏈球菌導致的牛奶發酵而產生的產品，長期以來對人類的身體健康有著很好的作用。在壹些文章中，人們總是集中在酸奶對於腸道新陳代謝的已有科學記錄的影響上(1, 23). 盡管有的作者在確認這些結論時失敗了，但酸奶中的乳酸菌確實可以改善個體對於乳糖不耐癥的乳糖消化能力，並能影響腸道的轉接時間(11),，刺激腸道免疫系統(2, 14, 31),，基於酸奶開胃菜的免疫刺激性能上的免疫學和基因學也已經開始進行研究。
Nevertheless, the scientific background of these studies and the application of the term “probiotic” to the starter bacteria L. delbrueckii subsp. bulgaricus and S. thermophilus are still strongly debated (13, 33). As indicated by Guarner et al. (13), recent scientific developments have challenged the validity and usefulness of the in vitro selection criteria traditionally pro-posed for probiotics.
然而，這些研究的科學背景和對於把開胃菌種德氏乳桿菌亞種，乳酸菌和鏈球菌作為益生素的應用還在被業界激烈爭論(13, 33). 如Guarner et al. (13)所示，最近的科學發展已經挑戰了傳統的對於益生菌的體外選擇標準的正確性和有用性
Traditional yogurt starters have nonhuman origins, and they (especially streptococci) are known to suffer from exposure to gastric acidic conditions (7) and to have a moderate ability to adhere to intestinal epithelial cells (12).
傳統的酸奶開胃菜擁有非人類起源，他們（特別是鏈球菌）被人熟知是因為他們暴露在胃酸環境中(7)，並且他們有適度的能力可以粘附在腸道上皮細胞上(12).
Survival during passage through the gastrointestinal tract is generally considered a key feature for probiotics to preserve their expected health-promoting effects (3).
通過胃腸道的幸存物通常被認為是益生菌的壹個主要特征，來保留他們對於促進健康的作用
There have been conflicting studies concerning the recovery of L. delbrueckii subsp. bulgaricus and S. thermophilus from fecal samples after daily yogurt ingestion.
每天飲用酸奶後通過對排泄樣品的研究，對於德氏乳桿菌亞種，乳酸菌和鏈球菌的愈合作用依然有很多有爭論性的研究
Some authors re-ported that L. delbrueckii subsp. bulgaricus and S. thermophilus were not recovered from feces of young (9) and elderly (26) subjects.
有壹些作者報告指出從試驗的老人和孩子的排泄物中發現德氏乳桿菌亞種，乳酸菌和鏈球菌並沒有恢復
On the other hand, Brigidi et al. (4) reported that for 6 days after the end of treatment, they recovered S. thermophi-lus from fecal samples from 10 healthy subjects who had in-gested a pharmaceutical preparation orally for 3 days.
另壹方面，Brigidi et al. (4)指出經過治療後6天中，他們從10個健康的試驗者的排泄物樣品中恢復了鏈球菌，這10個試驗者已經服用了3天的藥物制劑
The persistence of a yogurt culture in the human gut was also recently confirmed by Mater et al. (22), who studied 13 healthy volunteers fed yogurt containing rifampin- and streptomycin-resistant strains of S. thermophilus and L. delbrueckii subsp. bulgaricus.
酸奶菌在人類腸道的持續性最近也由Mater et al. (22)確認證實，Mater et al.研究了13個健康的誌願者，這些誌願者都已經喝過包含利福平和鏈黴素的耐藥菌株德氏乳桿菌亞種，乳酸菌和鏈球菌的酸奶