Liquid yogurt fermenter has been gradually eliminated by large-scale yogurt manufacturers due to its unstable quality and susceptibility to contamination, only some small and medium-sized yogurt factories are still in the joint production of some universities or research institutes; deep-freezing yogurt fermenter because of its deep-freezing chain of the cost is relatively high, the use of the wide range of restrictions; and direct-pitching type of yogurt fermentation agent in its price gradually accepted by the domestic manufacturers, it has been begun to promote the use of some large-scale yogurt manufacturers.
In the previous yogurt production process, yogurt fermentation agent strains in the yogurt manufacturer to set up a separate strain workshop to complete the "pure bacteria → activation → expansion of the propagation → mother fermentation agent → intermediate fermentation agent → work of the fermenter" this process, the process of work procedures, stringent technical requirements, the general manufacturers due to production conditions are limited, often resulting in quality problems. The process has many procedures and strict technical requirements, and general manufacturers often have quality problems due to limited production conditions. Therefore, in the dairy industry in developed countries, yogurt manufacturers do not make their own leavening agent, by specializing in the production of leavening agent enterprises to provide yogurt leavening agent to meet the requirements of fermented dairy products manufacturers. Denmark's Hansen Center Laboratory produced a super-concentrated direct-pitch yogurt fermenter at the end of 1988.
Directed Vat Set (DVS) refers to a series of highly concentrated and standardized freeze-dried fermenter strains that can be added directly to heat-treated raw milk for fermentation without the need for other pre-treatments such as activation and expansion. Direct-pitch yogurt fermenter has a viable bacterial count of 1010 - 1012 CFU/g. Due to the strong vigor and multiple types of direct-pitch yogurt fermenter, yogurt manufacturers can choose any type according to their needs, thus enriching the variety of yogurt products, and at the same time eliminating the need for a strain workshop, reducing the number of staff, investment and space, and simplifying the production process. Direct-pitch yogurt fermenter does not need to expand the culture, can be used directly, easy to manage. The production and application of direct-pitch yogurt fermenter can make the fermenter production specialized, socialized, standardized and unified, so as to standardize the production of yogurt, improve the quality of yogurt, and protect the interests and health of consumers.