carbohydrates delivered in food to the large bowel to provide fermentable substrates for selected bacteria. Most strains used as probiotics belong to the genus Lactobacillus. (Other probiotic strains used belong to the genus Bifidobacterium). Probiotics have been evaluated in research studies in animals and humans with respect to antibiotic-associated diarrhea, travellers' diarrhea, pediatric diarrhea, inflammatory bowel disease, irritable bowel syndrome and Alzheimer's disease. Future applications of probiotics have been conjectured to include delivery systems for vaccines and immunoglobulins, and the treatment of different gastrointestinal diseases and vaginosis. Foods The quest to find food ingredients with valuable bioactive properties has encouraged interest in exopolysaccharides from LAB. Functional food products that offer health and sensory benefits beyond their nutritional composition are becoming progressively more important to the food industry. The sensory benefits of exopolysaccharides are well established, and there is evidence for the health properties that are attributable to exopolysaccharides from LAB. However, there is a wide variation in molecular structures of exopolysaccharides and the complexity of the mechanisms by which physical changes in foods and bioactive effects are elicited. Some LAB produce bacteriocins which limit pathogens by interfering with cell wall synthesis or causing pore formation in the cell membrane. Nisin, a bacteriocin produced by LAB, was first researched as a food preservative in 1951 and has since been widely commercially used in foods due to its antimicrobial activity against Gram positive bacteria. Nisin is utilized as a food additive in at least 50 countries. In addition to having antibacterial activity, LAB can inhibit fungal growth. Various LAB, largely from genus Lactococcus and Lactobacillus, suppress mycotoxigenic mold growth due to the production of anti-fungal metabolites. Furthermore, LAB have the potential to reduce the abundance of mycotoxins in foods by binding to them. In a study for postharvest food product safety conducted with 119 LAB isolated from the rhizosphere of olive trees and desert truffles, mostly within the genera of Enterococcus and Weissella, researchers found strong antibacterial activity against Stenotrophomonas maltophilia, Pantoea agglomerans, Pseudomonas savastanoi, Staphylococcus aureus and Listeria monocytogenes, and anti-fungal activity against Botrytis cinerea, Penicillium expansum, Verticillium dahliae and Aspergillus niger. Fertilizer Researchers have studied the impact of lactic acid bacteria on indoleacetic acid production, phosphate solubilization, and nitrogen fixation on citrus. While most of the bacterial isolates, were able to produce IAA, phosphate-solubilization was limited to only one of the eight LAB isolates. Fermentation Lactic acid bacteria are used