Screening Of Antagonistic Bacteria Against Aspergillus Flavus And Its Application In Chili Sauce

Aspergillus flavus widely exists in nature.A variety of food crops are vulnerable to Aspergillus flavus pollution before and after harvest,storage or processing,resulting in all kinds of food waste,and some Aspergillus flavus can produce aflatoxin with strong toxicity.If you eat food containing such toxin for a long time or in large quantities,it will seriously threaten the health of people and animals.Therefore,in this experiment,Aspergillus flavus was used as the indicator mold,and the strains with antagonistic effect against Aspergillus flavus were screened from various fermented foods by biological control methods,and their antibacterial activity was preliminarily detected;Taking the degradation amount of AFB₁ as the response value,the conditions for the degradation of AFB₁ by antagonistic strains were optimized;Applied in the traditional fermented chili sauce,the effects of the addition of antagonistic strains on the sensory flavor and physical and chemical indexes of the actual products were preliminarily compared,so as to provide a certain experimental basis for the control of AFB₁ by using the traditional natural fermented chili sauce.The following are the main research results of this paper:1.The strain P-1 screened by plate confrontation method can significantly inhibit the growth of Aspergillus flavus,and the inhibition rate is 53.99%.Combined with morphological observation,biochemical test and 16S rDNA sequence analysis,strain P-1was determined to be Bacillus velezensis.2.The strain P-1 could make the conidia stalk of Aspergillus flavus uneven in thickness.The fermentation filtrate can reduce the budding of Aspergillus flavus spores.The bud tube of budding is thin,the growth is slow,and the top of hypha is thin,which can affect the formation of apical sac and the production of conidia;By comparing the dry weight of Aspergillus flavus silk ball,it was found that the main antibacterial active substance was the crude extract of lipopeptide extracted from P-1 fermentation filtrate.3.The fermentation conditions of strain P-1 degrading AFB₁ were optimized by single factor test and response surface test.NB medium was selected,2%glucose was added,pH was 7.0,inoculation amount was 5%,and the degradation rate of strain P-1 to AFB₁ was83.94%when cultured at 30.5℃for 2.6 days.4.When strain P-1 participates in the production of hot sauce,it has an impact on the flavor of hot sauce,reduces the spicy taste and spicy flavor of hot sauce,and the sauce flavor is stronger;The results of physical and chemical indexes showed that the addition of strain P-1 could increase the content of total acid and amino acid nitrogen in chili sauce and reduce the content of total sugar in chili sauce.