Host-adapted lactobacilli in food fermentations: impact of metabolic traits of host adapted lactobacilli on food quality and human health

Back-slopping of fermentation cultures in food fermentations can ensure stability of fermentation microbiota at the species or even at the strain level over extended periods of time. In contrast to the fermentation organisms in spontaneous food fermentations, which are derived from plant-associated or environmental micro-organisms, dominant micro-organisms in back-slopped fermentations are often recruited from lactic acid bacteria that are associated with insect or vertebrate hosts. Lifestyle-associated metabolic traits that relate to the ecological fitness of lactic acid bacteria in the host environment include biofilm formation through production of exopolysaccharides, acid resistance mediated by urease, glutaminase or glutamate decarboxylase, and polysaccharide hydrolysis mediated by extracellular glucosyl hydrolases. This review will discuss the ecological fitness of these organisms in food fermentations, and relate their specific metabolic properties to the safety, quality, and nutritional properties of food.