# Characterization and Selection of _Lactobacillus_ Strains with Potential Robotic Applications  
[PERSON]  
1 Department of Microbiology and Biotechnology, University of Food Technologies, 4002 Plovdiv, Bulgaria 1  
[PERSON] T. T.  
Probiotics and Prebiotics (ISAPP) confirmed and accepted minor grammatical corrections to the previously announced by FAO/WHO definition, retaining its scientific meaning. As defined by ISAPP, the term \"probiotic\" refers to \"many types of microorganisms, which demonstrate health benefits for the host, while remaining alive\" [2]. Although the exploration of probiotic strains is not a new concept, they continue to attract the attention of both the scientific society and the food industry sector. Amongst the most studied bacteria for probiotic potential are the members of the genera _Lactobacillus_ and _Bifidobacterium_, which are known as non-pathogenic inhabitants of animal and human gastrointestinal and female genital tracts [3; 4]. In addition, as a part of the normal microflora, they are frequently isolated from various dairy products and non-dairy sources [5; 6]. Lactic acid bacteria, in particular lactobacilli isolated from dairy products, are generally recognized as safe (GRAS) and extensively used as starter cultures and/or adjunct cultures to produce various fermented milk products, alcoholic beverages, sourdough and silage preparations [7]. Numerous studies have revealed that some other members of the LAB group, such as _Lactococcus_, _Pedicococcus_ and _Leuconostoc_, as well as strains belonging to the genera _Saccharomyces_, _Enterococcus_, _Streptococcus_, _Bacillus_, and _Escherichia_, have also exhibited promising probiotic properties [8]. The selection of probiotic strains is associated with certain important criteria for effectiveness, such as the capacity to survive the adverse upper gastrointestinal tract conditions (low pH, bile toxicity, digestive enzymes), the production of metabolites with antimicrobial activity (organic acids, bacteriocins, H\({}_{2}\)O\({}_{2}\)), antibiotic resistance and the ability to adhere to the epithelial intestinal cells, thus colonizing the intestines and exerting their health-promoting effects [5; 9]. The beneficial effects of probiotic LAB strains are reported to involve antimicrobial, gastroprotective, anti-mutagenic, anti-carcinogenic, immunomodulating, cholesterol-reducing [10] and antioxidant [11] activities. These therapeutic features are species- and even strain-dependent. Undoubtedly, the crucial role of _Lactobacillus_ spp. is associated with the immunity and gastrointestinal health of the host, which are closely related to intestinal barrier integrity. _In vitro_ studies have revealed that some _Lactobacillus_ species, with their metabolites, stimulate mucin production by the enterocytes, thus enhancing the intestinal barrier. The short-chain fatty acids (acetate, propionate and butyrate), H\({}_{2}\)O\({}_{2}\) and antimicrobial peptides (bactericins) produced by the probiotic strains or secreted by the organism after stimulation are also important factors in improvement (stabilization) of the intestinal cell junction and play a key role in defense against pathogenic microorganisms. An important property of some _Lactobacillus_ species is the stimulation of the secretion of immunoglobulin A (IgA) by intestinal B-cells (located in Peyer's patches and lamina propria), resulting in an increase in local immunity [12]. Apart from that, probiotic microorganisms, with their physiological functions, contribute to maintaining gastrointestinal health.