Food and Nutrition Sciences, 2014, 5, 1765-1775 Published Online September 2014 in SciRes. http://www.scirp.org/journal/fns http://dx.doi.org/10.4236/fns.2014.518190 How to cite this paper: Quinto, E.J., Jiménez, P., Caro, I., Tejero, J., Mateo, J. and Girbés, T. (2014) Probiotic Lactic Acid Bac- teria: A Review. Food and Nutrition Sciences, 5, 1765-1775. http://dx.doi.org/10.4236/fns.2014.518190 Probiotic Lactic Acid Bacteria: A Review Emiliano J. Quinto 1* , Pilar Jiménez 1 , Irma Caro 1 , Jesús Tejero 1 , Javier Mateo 2 , Tomás Girbés 1 1 Department of Food Science and Nutrition, Faculty of Medicine and CINAD (Centro de Investigación en Nutrición, Alimentación y Dietética; Edificio Lucia), University of Valladolid, Valladolid, Spain 2 Department of Food Hygiene and Technology, Faculty of Veterinary Medicine, University of León, León, Spain Email: * equinto@ped.uva.es Received 11 June 2014; revised 18 July 2014; accepted 12 August 2014 Copyright © 2014 by authors and Scientific Research Publishing Inc. This work is licensed under the Creative Commons Attribution International License (CC BY). http://creativecommons.org/licenses/by/4.0/ Abstract Lactic acid bacteria (LAB) play a critical role in food production and health maintenance. There is an increasing interest in these species to reveal the many possible health benefits associated with them. The actions of LAB are species and strain specific, and depend on the amount of bacteria available in the gastrointestinal tract. Consumers are very concerned of chemical preservatives and processed foods. However, products with or processed with LAB are accepted as a natural way to preserve food and promote health. This paper aimed to review the recent data in regard to the role of probiotic LAB in the preservation of foods, in the immunomodulation in the gastrointesti- nal tract, and in its health benefits. Keywords Lactic Acid Bacteria, Probiotic, Gastrointestinal Tract, Health 1. Introduction Lactic acid bacteria (LAB) are a group of Gram-positive, non-sporulating, anaerobic or facultative aerobic cocci or rods, which produce lactic acid as one of the main fermentation products of the metabolism of carbohydrates [1]. The monograph published by Orla-Jensen [2] is the base of the present classification of lactic acid bacteria (LAB) using the following criteria: cellular morphology, mode of glucose fermentation, range of growth tem- perature, and sugar utilization patterns. Four genera were recognized as LAB: Lactobacillus, Leuconostoc, Pe- diococcus, and Streptococcus. Molecular biological methods have increased the number of genera included in this group [3]. The current taxonomic classification includes the LAB group in the phylum Firmicutes, class Ba- cilli, and order Lactobacillales. The different families and genera can be search in the NCBI Taxonomy Browser * Corresponding author.