Screening Of The Lactobacillus Plantarum With Inhibition Activity To The Penicillium Roqueforti And Applying To Silage

In this paper, choose 347 Lactobacillus plantarums isolated from traditional fermented foods in Inner Mongolia, Xinjiang, Qinghai, Tibet, Gansu, Yunnan, Sichuan and Mongolian region, use the method of dual culture agar plate assay to select strains which can inhibiting the growth of Penicillium roqueforti. According antibacterial activity and antibacterial properties of selected Lactobacillus to find more suitable strains, and also studying their application of silage.Add 347 Lactobacillus strains by 5%(Ⅴ/Ⅴ) in MRS medium, after fermented at 37 ℃ for 48 hours, take inhibition zone of Penicillium roqueforti as an indicator, through the method of dual culture agar plate assay, selected thirty-three antibacterial L. plantarum which inhibition zone diameter greater than 25mm. Use the thirty-three high antibacterial activity fermentation strains to do a series tests:acid resistance test, temperature tolerance test, the strain growth rate and acid production rate test, found that: Among thirty-three Lactobacillus, there are twelve with good acid resistance in acidic conditions (pH= 2) and have antibacterial activity; Among twelve Lactobacillus, IMAU80162、IMAU10380、IMAU10585、IMAU20013andIMAU20020 could grow in 10,25 (room temperature),37,45 ℃ and has good antibacterial effect at 25 ℃.By further screening found that among five Lactobacillus, there are three not only grow fast, but also can be produce large amounts of acid in a short time and reduce the environmental pH values, which are IMAU80162、IMAU10585 and IMAU20013. IMAU80162、IMAU10585 and IMAU20013 were inoculated alone or mixed(1:1) with 5.30 lg cfu/g of total inoculation volume to silage. The changes of pH and microbial groups in silage were monitored during twenty-eight days fermentation at 25 ℃ (0、1、 3、5、7、14、21、28d).The dynamic changes of Lactobacillus and sundry microbes (yeasts, moulds and E. coli) were determined using selective media. The results showed that 7 days after the fermentation the active numbers of IMAU80162 and IMAU10585 in silage is 8.98 lg cfu/g, more than other groups. The complex fermentation group IMAU10585 and IMAU20013 growth fastest, reaching a maximum (8.34 lg cfu/g) at the third day.28 days after the fermentation, the active number of moulds, yeasts and E. coli were significantly lower than the control group (P<0.05). Among them, the best inhibitory effect on moulds is complex fermentation group IMAU80162 and IMAU20013; the best inhibitory effect on yeasts is complex fermentation group IMAU10585 and IMAU20013; the best inhibitory effect on E. coli is single fermentation group IMAU10585. The pH of the tested groups decreased noticeably,28 days after the fermentation, the pH of single fermentation group IMAU10585 significantly lower (P<0.05) than the control groups. The lactic acid content of the tested groups were higher than the control groups.Consolidated results showed that L. plantarum IMAU80162、IMAU10585 and IMAU20013 can inhibit the growth of sundry microbes and reduce the pH in silage, so it can be used as potential silage additives and do further research.