There are several other similar factors that might provide the advantage to the live probiotics. acidophilus but not for the unwanted pathogenic forms. e.g., the release of primary and secondary metabolites like fatty acids lowers the pH which is just perfect for the rapid growth of L. But once they start growing they can curve out a niche of their own making the conditions congenial for their growth while the same will be harsh for the survival of other microbes. While the live cells with their own sets of added advantages may take time to come out of the lag phase as it may be in a lyophilized form and germinate to show their qualities. The probiotics are marketed in a variety of forms-live cells, heat inactivated or dead cells, parts of cells either as lyophilized powder or alongwith yoghurt, curd, whey. The same policy can be adopted to overcome different adverse physiological conditions within the human body. This goes on to suggest that a mixture of different strains with varied utilizing ability of substrates that might be on offer can be used. Similarly, the growth rate is accelerated upon addition of amino acids or growth factors like ascorbic acid. e.g., under in vitro conditions, the lactulose utilization varies between strains of Lactobacillus and Bifidobacterium. Studies on the growth pattern of different strains of probiotics show a great degree of variability between their substrate specificity. But before that a precise characterization of the growth characteristics of the probiotics in use has to be done. The trait can be put to use in patients with digestive malfunction. Nonetheless, the bacteria with smaller doubling time can eventually aid in the digestion of the food and even prevent food poisoning. However, there are strains that have a comparatively large generation time in vivo and consequently they are unable to show such colonization of food during its movement. This is a short enough time to get growth within the food as it moves along through the digestive system. The average doubling time of the species of most of these bacteria is mostly in the range of 2-3 hours in the intestinal tract. Generally, there are many strains of Lactobacillus and Bifidobacterium that have a very short generation time. Once that is done it can easily achieve its goal to flourish rapidly and outnumber the undesirable or pathogenic bacteria, the so called ‘bad bugs’ of the body. One of the proposed modes of action of the probiotic bacteria to exert its beneficial effects is to have a rate of proliferation greater than that of its colonial competitors. Whether a bacterial species can work very fast has to do largely to its generation time. The generation time of a bacterium is defined as the time taken by it to double its numbers.