*Lactic Acid Bacteria: Review on the Potential Delivery System as an Effective Probiotic DOI: http://dx.doi.org/10.5772/intechopen.111776*

organisms play two key roles in the ecosystem, and these two distinct roles include being used as starter cultures in the dairy industries and being used as probiotic cultures. Lactobacillus species are usually used in the food industries (especially dairy industries) with other bacteria species such as streptococcus as a starter culture for fermentation during the manufacture of products such as yogurt, cheese, and sour milk. This is due to the ability of the lactobacillus to convert the sugar lactose into lactic acid to produce dairy products. Lactic acid is the major byproduct, which forms the larger percentage (at least 85%) of metabolic end products in numerous species, including *Lactobacillus acidophilus, Lactobacillus casei, and Lactobacillus plantarum*, indicating that glucose metabolism is primarily homofermentative. Many Lactobacillus strains are also isolated from different sources to be used as probiotic agents; however, it is unlikely that each species/strain possesses all the desired characteristics that will make it a suitable probiotic. Lactobacillus species are also used in the production of pickles and sauerkraut (fermented vegetables), wines and juices (beverages), and other products such as sourdough bread and sausages. The widespread utility of this microbe (Lactobacillus) is generally due to its Generally Recognized as Safe (GRAS) status, which makes a lot of people like its products. Lactobacilli are fastidious LAB and can be found in a variety of nutrient-rich environments such as dairy environments, microbial-rich host habitats such as human and other mammals' mucosal surfaces, and natural ecological niches such as decaying organic matter, soil, and insects' gastrointestinal (GI) system [2]. Also, Lactobacillus species are mostly found in various fermented foods, such as yogurt, as well as in nutritional supplements. Lactobacillu*s* can also be usually found in the crop and ileum flora of poultries, since these are good probiotics for the poultry thus promoting the growth of the bird and suppressing the growth of diseases causing bacteria in the poultry [8].
