Characteristics Of Antimicrobial Substance Produced By Lactobacillus Helveticus

The antimicrobial activity of lactic acid bacteria were screened from traditional dairy yogurt in Inner Mongolia by the double agar plate diffusion method,and provide characteristics of antibacterial substances were researched in order to provide theoretical data for developing food preservation.The results were as follows:Two strains of Lactobacillus Bacillus Subtilis and Salmonella Typhimurium were screened by antimicrobial activity test,the two strains of BY54-1 and BY47-3 were identified by physiological and biochemical identifications,and 16 SrRNA gene fragment analysis.The BY54-1 strain and BY47-3 were Lactobacillus.After the exclusion of hydrogen peroxide and organic acid,the bacteriostatic diameter of Swiss Lactobacillus BY54-1 is 19.89 mm and 19.78 mm,respectively,while the bacteriostatic diameter of BY47-3 is 17.68 mm and 17.53 mm,the antibacterial substances produced by BY54-1 and BY47-3 have antibacterial activity to Bacillus Subtilis and Salmonella Typhimurium.The antibacterial activity of the supernatant decreased significantly after fermentation and reaction with trypsin,protease K,pepsin and papain,so the antimicrobial substance has protein.The antibacterial substance has an inhibitory effect on Bacillus subtilis during pH2.0-5.0,and on Salmonella typhimurium during pH2.0-5.5.After 121? 30 min,The bacteriostatic diameter of BY54-1 and BY47-3 were 17.38 mm,16.89 mm and 16.78 mm,19.25 mm to Bacillus Subtilis and Salmonella Typhimurium,and has good heat stability.The results showed that the antibacterial substances produced by Lactobacillus BY54-1 and BY47-3 were insensitive to surfactants,organic solvents and metal ions.