Lactic acid bacteria from sourdough with anti-microbial properties

During recent years, the most viable approach to chemical additives for sourdough-based products is biological preservation using lactic acid bacteria (LAB) owing to their generally regarded as safe and qualified presumption of safety (QPS) status in the United States of America and the European Union. Numerous LAB species have so far been found in sourdoughs from various parts of the world. LAB are generally crucial for the microbiological safety and preservation of fermented foods. The final product produced at the end of fermentation maintains microbiological stability as a result. Bread and other leavened baked foods can be contaminated with bacteria and yeasts that lead to degradation, and LAB exhibits anti-bacterial and anti-fungal activity. Adding sourdough is one of the best strategies for preventing bread spoilage. In this way, a product that is suitable for consumer demands and without any additives is produced. Organic acid production, proteolytic activity, volatile component synthesis, and anti-fungal capabilities are all metabolic properties of LAB that delay staling and improve flavor in the bread. The most common deterioration in bakery products is caused by fungal growth. Baked products may be contaminated with Bacillus spores that survive the baking process; yeasts especially Zygosaccharomyces and Pichia genera that colonize the surface and adversely affect the organoleptic characteristics; and molds that are categorized under the genera Aspergillus, Penicillium, and Cladosporium that change the color and organoleptic properties and, in some cases, may produce mycotoxins. This represents a concern to public health due to their capacity to synthesize mycotoxins. Fungicides are added to typical bread in most bakeries to avoid the formation of mycotoxins that are detrimental to human health. anti-fungal chemicals identified in the bread included lactic acid, acetic acid, carbon dioxide, diacetyl, hydrogen peroxide, caproic acid, 3-hydroxy fatty acids, phenyl lactic acid, cyclin dipeptides, reuterin, and fungicins produced naturally by LAB in sourdough. It has been found to be effective in preventing the formation of mycotoxins. In addition, it is common knowledge that LAB provide beneficial contributions to the natural microbiota found in the digestive systems of animals and humans and can show combatant effects against pathogenic microorganisms. Furthermore, LAB's anti-bacterial function is the outcome of nutritional competition with pathogenic microorganisms. Sourdough LAB can also inhibit other microorganisms by producing bacteriocin or bacteriocin-like inhibitory substances and exopolysaccharides (EPSs). Thus, the utilization of cultures capable of producing bacteriocin and/or EPS as starter or preservation cultures, as well as their application as food additives, may contribute to the objective of providing safer food. This chapter gives a broad review of evaluating the anti-bacterial and anti-fungal characteristics of LAB strains from sourdough-based products.