The prospect of using nisin for pre-milking treatment of the udder of cows

Abstract

Bacteriocins, in particular, nisin, are increasingly used for the development of sanitizing agents along with natural antimicrobial substances, such as organic acids, essential oils, alcohols, and others. The purpose of the work was to investigate the bactericidal effect of nisin on test cultures of microorganisms that cause mastitis in cows for its use in means for pre-milking treatment of the udder in combination with lactic acid. The minimum inhibitory concentration was studied on test cultures of Staphylococcus aureus (ATCC 25923), Escherichia coli (055К59 №3912/41) and Streptococcus uberis (field strain) by the method of serial dilutions with exposures of 30 seconds and 10 minutes. In the experiment was used nisin produced by Glory Chem Co., Ltd. (China), lactic acid food 80 % solution (“Klebrig”, Belgium). It was established that the minimum inhibitory concentration of nisin after exposure for 30 seconds on S. aureus cultures was 1.0 % and Str. uberis – 0.125 %. Nisin at the content of 2 % and 1 % in the solution did not show the minimum inhibitory concentration on E. coli cultures within 30 seconds, but inhibited 91.7 and 82.3 % of the microflora, respectively, at this concentration. It was found that the minimum inhibitory concentration of lactic acid after exposure for 30 seconds on S. aureus and E. coli cultures was 2 %, and on Str. uberis – 1 %. At the same time, lactic acid diluted below the minimum inhibitory concentration, in particular, 1 % and 0.5 %, inhibited 98.9–96.5 % of microorganisms in the solution, which may be sufficient for its use in means for processing the udder of cows before milking and at lower concentration. The study of the bactericidal effect by the well method showed that nisin exhibits a synergistic bactericidal effect with lactic acid and can be used in combination to create a means for pre-milking treatment of the udder of cows. Therefore, in order to create means for pre-milking treatment of the skin of udders of cows, it is necessary that the working concentration of nisin be from 0.5 to 1.0 %, and lactic acid from 1 to 2 %.