Screening Of Antagonistic Bacteria Against Black Pepper And Its Inhibitory Effect

Black pepper is one of the oldest and best-known spices in the world, and is rightly called "King of Spices". Now cultivated extensively in tropical countries.High temperature, high rainfall and relative humidity in these growing areas are highly conducive for fungal proliferation and mycotoxin production which have posed threats to the quality and edible safety for black pepper. Bio control bacteria have been widely used in food preservation and grain storage. This paper aim to isolate, screen, and identify bacertia from raw materials such as the Sichuan pickles, commercially available yogurt,fermented meat and series of spices which have strong ability to inhibit the growth of Aspergillus flavus. The main research results are as followed:(1) 223 strains were isolated from the raw materials,31 strains with higher antifungal ability were preliminarily screened out and 9 strains were isolated from surface of spices. another 22 strains mainly were from pickle waters and sausage. With the extend of training time, the antifungal ability of Lactic Acid Bacteria declined and finally, the strain F1 with highest and strong antifungal activity (58.8%) was screened out from BP. According to results of the physiological and biochemical identification and 16S rDNA sequence analysis, the strain F1 was Bacillus amyloliquefaciens.(2) After the optimization of the cultural conditions and medium components of B. amyloliquefaciens F1, the antifungal activity of the fermentation supernatant had been increased 60% and also had strong inhibit ability to Aspergillus niger (62.8%), white Aspergillus(66.3%), Aspergillus parasiticus(14.3%) respectively which indicated that the F1 strain had a broad-spectrum antibacterial activity. After separation and concentration of supernatant by ultrafiltration membrane, the antifungal test proved that the antifungal substance was macromolecules between 30 ku-100 ku. The ultrafiltrate could endure a certain degree of high temperature. After digestion by Trypsin, the antifungal activity of ulterfiltrate declined 70% which showed that tthe antibacterial substance are proteins.(3) The effects of ultrafiltrate on the growth of Aspergillus flavus and AFB1 generation and its application on BP storage were studied. The results of the weight of dry mycelium showed that the ultrafiltrate could inhibit the germination of spores and delayed the development of hyphae. The detection results of AFB1 concentration in fermentation liquid by HPLC method showed that the crude protein contained in ultrafiltrate antifungal ultrafiltrate could also reduce the generation of aflatoxin. The ultrafiltrate was applied to prevent the Aspergillus infection on BP storage. According to the changes of mould accounts, dry matter, piperine, essential oil and volatile compounds we could conclud that mould metabolism could lead to the ease of dry matter. Piperine and essential oil were more easily extracted while the nutrients of BP were broken down by mould. However, the volatile compounds were significantly changed which brought about flavour changes of BP. Our research demonstrated that the antifungal substances in ultrafiltrate could resist the decomposition of BP organization and slack other harmful effects. The B.amyloliquefaciens Fl has potential application value.