Timely approaches to identify probiotic species of the genus Lactobacillus

Over the past decades the use of probiotics in food has increased largely due to the manufacturer’s interest in placing “healthy” food on the market based on the consumer’s ambitions to live healthy. Due to this trend, health benefits of products containing probiotic strains such as lactobacilli are promoted and probiotic strains have been established in many different products with their numbers increasing steadily. Probiotics are used as starter cultures in dairy products such as cheese or yoghurts and in addition they are also utilized in non-dairy products such as fermented vegetables, fermented meat and pharmaceuticals, thereby, covering a large variety of products. To assure quality management, several pheno-, physico- and genotyping methods have been established to unambiguously identify probiotic lactobacilli. These methods are often specific enough to identify the probiotic strains at genus and species levels. However, the probiotic ability is often strain dependent and it is impossible to distinguish strains by basic microbiological methods. Therefore, this review aims to critically summarize and evaluate conventional identification methods for the genus Lactobacillus, complemented by techniques that are currently being developed.