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ABSTRACT: The aims of this study were to investigate the recovery of Lactobacillus casei Shirota (LcS) from the intestine of healthy Indonesian volunteers after consumption of fermented milk containing LcS, and its impact on the population of Enterobacteriaceae faecal microbiota. Twenty six healthy individuals were selected and asked not to consume fermented milk for 10 days as washout period, followed by 10 days of daily consumption of fermented milk containing 6.5 x10^sup 9^ CFU LcS as ingestion period, and 10 days of not consuming fermented milk (follow up period). Feces of volunteers were collected three times i.e., at the ends of wash out period, ingestion period, and follow up period. This study showed that consumption of fermented milk for ten days was able to bring feces of all the volunteers with the level of LcS reaching to 6.6 ± 0.6 log^sub 10^ CFU/g wet feces. The presence of this bacteria indicated that LcS was able to colonize in the gastrointestinal tract. This study also observed the decrease in the numbers of Enterobacteriaceae, Escherichia coli, and Coliform non E.coli in almost half of the volunteers after ingestion of fermented milk containing LcS.
KEY WORDS: Defecation frequency; Faecal quality; Fermented milk; Intestinal microbiota; Lactobacillus casei Shirota
INTRODUCTION
Many studies have supported the beneficial effect of probiotic for human health. The probiotic efficacy relies on their ability to survive in the digestive system and be able to proliferate in the gut. The viability of probiotic depends on the strain used and also the intrinsic and extrinsic factors. The ability of Lactobacillus and Bifidobacterium to survive in the gastrointestinal tract varies considerably between species. Ingested bacteria are exposed to adverse conditions when they reach stomach. The survival in the stomach depends on the time required by the bacteria to leave the stomach. The gastric emptying rate is obviously an important feature for the survival of bacteria. The small intestine, especially its proximal part, contains hydrolytic enzymes and bile salts known to have lethal effect on microorganisms. Thus the passage through this compartment may also significantly affect the survival of ingested bacteria.
Factors such as type and composition of food consumed, life style, age, environment and race have known to have influence in the gastric emptying rate, thus...