**6. Lactobacillus as a starter culture for the dairy industry**

*Lactobacillus* and other related species have been utilized as starter cultures for fermentation operations in a wide range of industries. Starter cultures are therefore regarded as an important component of basically fermented foods produced commercially, and nonetheless, these starter cultures are composed of useful microbes

such as *Lactobacillus* which are directly introduced into the various food components, which help to produce the desired and predict the occurrence and characteristics in the finished product, which is the food [73].

Several fermented foods can indeed be produced without the need for a starter culture; however, adding a concentrated number of microorganisms such as *Lactobacillus* as a starter culture makes a difference and ensures that the food has desired characteristics such as the extension of shelf life, increased nutritional value benefits, altered sensory aspects, and an increase in economic value. According to Durso and Hutkins [73], several local methods for creating starter cultures for LAB involve backslopping or inoculating (introducing into) a fresh batch with a little quantity of the completed, particularly preserved product.

Other ways for starter culture production include harnessing microorganisms naturally found on the product and using specific containers that allow the starter culture microbes to survive within cracks and holes. These traditional fermentation procedures, however, allow for the creation of a variety and distinct fermented foods and drinks, and they are still utilized in small- to medium-scale manufacturing facilities, as well as in developing nations. These techniques of creating starter cultures, on the other hand, are prone to delay or failure fermentations, contamination, and variable product quality [73]. Following the discovery that pure cultures could be used to mature milk in the late 1880s by a team of scientists led by Storch of Denmark, Weigman of Germany, and Conn of the United States, the significance of flavor-producing bacteria (i.e., citrate-fermenting diacetyl-producers) was quickly established. Therefore, Christian Hansen established a starter culture business in 1978 based on this knowledge, and it has since grown to become a significant starter culture provider to industries such as brewing, dairy, baking, wine, and meat industries. In the past, producer-created starter culture strains were made by growing pure strains in heat-sterilized milk. These liquid cultures are still useful and well-liked today, despite having a short lifespan because of the loss of cell viability activities due to fermentation. Another technique of culture preparation, known as the crude dry culture preparation method, was devised; nevertheless, this method required multiple milk transfers to activate and respond to the culture. Freeze-dried cultures that were first produced in the 1960s are now noted to be one of the dairy cultures being used widely in the food industries. These cultures now dominate the starter culture industry because of the major advancements in freezing and freeze-drying methods. Given that starter culture bacteria's primary function is to ferment sugars and create acids, the capacity of LAB to metabolize carbohydrates is very essential.
