Lactic bacteria as probiotics, food bio-preservatives and producers of bacteriocins: a review

Abstract

Lactic acid fermentation is an important technique used in food preservation, resulting from natural fermentation by indigenous lactic acid bacteria (LAB) that are part of the natural microbiota of the food. LAB can also be intentionally added to foods to impart intrinsic sensory characteristics, such as aroma, flavor, and texture, as well as functional, probiotic characteristics, the ability to reduce pH, and inhibit the multiplication of undesirable microorganisms. LAB can produce several compounds, such as lactic acid, acetic acid, diacetyl, hydrogen peroxide, enzymes and bacteriocins that perform several activities, including biopreservation, which is desirable for foods, as it replaces the addition of preservative substances and additives to products. These characteristics of BAL meet the consumer market's demand for foods with functional claims, more natural and with the addition of a smaller amount of ingredients. Given the above, this literature review aims to show the applications of LAB as probiotics, producers of bacteriocins and food biopreservatives, and to point out the challenges for future studies. In foods, some LAB strains are recognized and authorized by official regulatory organizations as probiotics and can be added to foods. Among the bacteriocins produced by BAL, nisin is authorized and marketed in different countries and stands out for its action against pathogenic microorganisms. Many studies evaluate the probiotic activity of various LAB strains isolated from foods and show their probiotic potential, as well as the production of bacteriocins and in vitro antimicrobial activity against pathogens and spoilage agents. However, research is still needed to identify new LAB and their metabolites, evaluate their safety and resistance to gastrointestinal tract conditions, identify the mechanisms of action, evaluate the technological properties and determine protocols for their application in the food industry.