Development of the product for pre-milking cow-udder care on the basis of nisin and lactic acid

Abstract

Nisin is a natural antibacterial substance widely used in the food industry and other spheres. As nisin has no bactericidal effect on gram-negative bacteria, it is combined with organic acids. The work aimed at developing a product for pre-milking cow udder care based on nisin and lactic acid. The bactericidal effect of the solutions of nisin and lactic acid was determined using the method of radial diffusion in agar on test cultures S. aureus (ATCC 25923), E. coli (055К59 №3912/41), and Str. uberis (field strain). In the experiment was used nisin produced by Glory Chem Co., Ltd. (China), lactic acid food 80 % solution (“Klebrig”, Belgium). The content of lactic acid in 1.5 % solution was sufficient for detecting bactericidal action on cultures S. aureus і Str. uberis, and 2 % for E. coli. Nisin solution had a lower bactericidal effect on coccal forms of micro-organisms compared to lactic acid and was ineffective for gram-negative rods. S  aureus cultures were sensitive to nisin in the case of 1,5 and 2 % content in the solution, and Str. uberis – in the case of 0.5 to 2 %. The study showed that the minimal substance content in the study variant of the agent was 1 % nisin and 1 % lactic acid, to which E. coli and S. aureus cultures are sensitive, and Str. uberis – highly sensitive. In the case of 1 % nisin and 1.5 % lactic acid content, all the studied micro-organisms are sensitive to such substances combination. In the case of the content of 1 % nisin and 2 % lactic acid, they are practically susceptible. Thus, when combined, nisin and lactic acid enhance each other's bactericidal effect and are more effective when used on test cultures of micro-organisms than they are separately. We have developed the studied agent variant for pre-milking cow udder care with the content of nisin – 1 %, lactic acid – 2 %, glycerine – 4 %, allantoin – 0.5 %, and water up to 100 %. The minimum inhibitory concentration of the agent in case of 30-second exposition on test cultures S. aureus and E. coli was in case of dissolution 1:1 and for Str. uberis – in case of dissolution 1:15.