Study On The Control Of Aspergillus Flavus And Its Aflatoxin B₁ In Stored Dried Pepper

Chili（Capsicum annuum L.）is one of the main characteristic cash crops in Guizhou,but it is vulnerable to the contamination of Aspergillus flavus（A.flavus）and aflatoxin B₁（AFB₁）during planting,drying,transportation and storage.Moldy dried chili not only cause huge economic losses,but also seriously damage human health.This study collected dried red chili from ten main varieties in the province,isolated and identified the main contaminated fungi.By controlling the growth conditions of A.flavus and biological control,it provided a theoretical basis for solving the control of A.flavus and AFB₁ in dried red chili storage.The main research findings are as follows:1.Samples of dried red chili from 10 main varieties were collected from Guizhou province,and the pathogenic fungi in the dried red chili were isolated and purified.After morphological and molecular identification,a total of 56 fungi were isolated from dried red chili,including 6 strains of A.flavus,of which 4 strains were toxin producing A.flavus.2.Through single factor experiments and response surface optimization experiments,the growth of A.flavus and its production of AFB₁ could be effectively controlled when the temperature was 5.13℃,O₂ concentration was 6.76%,and CO₂concentration was 6.42%when using a controlled atmosphere warehouse to store dried red chili.3.Selected a Bacillus subtilis E11 strain as a biocontrol bacterium for dried red chili during storage.E11 had a strong inhibitory effect on the hyphae of four strains of A.flavus and AS 3.4408,and could reduce AFB₁ by 81.34%at 24 hours.Scanning electron microscopy observation revealed that the fermentation supernatant of E11could cause deformation and shrinkage of A.flavus hyphae.E11 and AS 3.4408 were co-cultured with dried red chili for 10 days,and it was found that E11 significantly inhibited the growth of A.flavus on dried red chili and maintained the quality of dried red chili.Compared with the control group,the yield of AFB₁ in dried red chili added with E11 bacterial solution decreased by 51.79%.This study found that optimizing the growth conditions of A.flavus and combining biological control with spraying E11 bacterial solution could effectively control the growth of A.flavus and the production of AFB₁.The research provides technical support for the safe storage of dried red chili and theoretical basis for extending the shelf life of dried red chili.