Screening,identification and antagonistic effect of antagonistic bacteria JTFM1001 against aflatoxin contamination in corn

Aflatoxin is a strong carcinogenic and toxic fungal toxin produced by Aspergillus flavus and other Aspergillus species,and can seriously threaten the health of consumers,thus becoming a global concern.Corn,as an important oil and economic crop,is highly susceptible contaminated by aflatoxin.In this study,antagonistic bacteria with strong inhibitory effect on aflatoxin were screened to provide support for the treatment aflatoxin contamination control in corn.Ten strains which have strong antagonistic effects against A.flavus were isolated from healthy corn from different corn producing areas in China.Among them,the antagonistic bacteria JTFM1001 through corn kernels in vivo and field experiment,the inhibition effect of aflatoxin contamination reached above 70%and 55%,respectively.And the strain was identified as Bacillus subtilis based on its morphological,physiological and biochemical characteristics and phylogenetic analysis of 16S rDNA.In addition,our data showed that it can colonize in the rhizosphere and survive for a long time,forming the dominant flora,with broad application prospect.Finally,we were surprised to find that the antibacterial metabolites secreted by the antagonistic bacteria was one of the mechanisms of its inhibition of A.flavus and aflatoxin.This will provide us with new ideas and perspectives on the effective prevention and control of aflatoxin contamination in corn and corn oil.

Influencing Factors and Biological Control of Aflatoxin Contamination in Peanuts

Peanut is an important economic crop and oil crop in China. It is vulnerable to infection by Aspergillus flavus during production,storage,transportation and processing,causing aflatoxin（ AFT） contamination. This paper introduced the status and characteristics of AFT contamination in China,analyzed the infection pathways and influencing factors of A. flavus,and discussed the prevention and control technology of AFT contamination in peanuts from the view of the use of beneficial microorganisms.

Aflatoxin Contamination and Rancidity in Locally Processed Commercial Fish Feeds and Ingredients along the Value Chain in Wakiso and Kampala Districts, Uganda

Aflatoxin contamination and rancidity in locally processed commercial fish feeds and ingredients along value chains is a Public and Animal health hazard. The study established the level of aflatoxin contamination, peroxide value (PV), Anisidine value (AnV), and their associated factors at storage areas among farmers, processors, traders, factories, and landing sites in the Wakiso and Kampala districts. The value chain actors were purposively selected in a cross-sectional study based on access to the feed store and the use of locally processed commercial fish feeds on farms. Data collected were statistically analyzed in SPSS version 20. All the samples (45) were positive for aflatoxin contamination and PV with 51% (23/45) of samples being contaminated with “above acceptable” aflatoxin levels and 66.6% (30/45) of samples with “above acceptable” PV. The overall percentage of “above acceptable” AnV was 11/29 (37.9%). Samples from factories were within acceptable contamination levels. Multivariate logistic regression analysis revealed no significant difference between aflatoxin contamination, peroxide, and Anisidine value with storage factors for locally processed commercial fish feeds and ingredients. The study recommended the purchase of fish feeds from factories and a larger study on storage factors responsible for aflatoxin contamination and rancidity in fish feeds in Uganda.

Drought Stress and Preharvest Aflatoxin Contamination in Agricultural Commodity: Genetics, Genomics and Proteomics

Throughout the world, aflatoxin contamination is considered one of the most serious food safety issues concerning health. Chronic problems with preharvest afiatoxin contamination occur in the southern US, and are particularly troublesome in corn, peanut, cottonseed, and tree nuts. Drought stress is a major factor to contribute to preharvest afiatoxin contamination. Recent studies have demonstrated higher concentration of defense or stress-related proteins in corn kerners of resistant genotypes compared with susceptible genotypes, suggesting that preharvest field condition （drought or not drought） influences gene expression differently in different genotypes resulting in different levels of ＂end products＂： PR（pathogenesis-related） proteins in the mature kernels. Because of the complexity of Aspergillus-plant interactions, better understanding of the mechanisms of genetic resistance will be needed using genomics and proteomics for crop improvement. Genetic improvement of crop resistance to drought stress is one component and will provide a good perspective on the efficacy of control strategy. Proteomic comparisons of corn kernel proteins between resistant or susceptible genotypes to Aspergillus flavus infection have identified stress-related proteins along with antifungal proteins as associated with kernel resistance. Gene expression studies in developing corn kernels are in agreement with the proteomic studies that defense-related genes could be upregulated or downregulated by abiotic stresses.

Aflatoxin contamination in food crops:causes,detection,and management:a review

Mycotoxins are secondary metabolites produced by several fungal species and molds.Under favorable conditions like high temperature and moisture,they contaminate a large number of food commodities and regional crops during pre and post-harvesting.Aflatoxin is the main mycotoxin that harm animal and human health due to its carcinogenic nature.Aflatoxins are mainly released by Aspergillus flavus and Aspergillus parasiticus.AFB1 constitutes the most harmful type of aflatoxins and is a potent hepato-carcinogenic,mutagenic,teratogenic and it suppresses the immune system.To maintain food safety and to prevent aflatoxin contamination in food crops,combined approaches of using resistant varieties along with recommended farming practices should be followed.This review concentrates on various aspects of mycotoxin contamination in crops and recent methods to prevent or minimize the contamination.

Geographical distribution of Aspergillus flavus in peanut harvest period in China

In order to grasp the distribution of Aspergillus flavus in the soil of peanut production areas in China,A.flavus biomarkers were tested on 555 soil samples from 37 sampling points in 17 provinces,peanut fields in four agroecological zones(Southern area,Yangtze River Basin,Northern area,Northeast area).The results showed that(1)the cultivation amount of A.flavus per gram of soil in the Yangtze River Basin is 1.30 times that of the southern area,1.56 times that of the northern area,and 6.20 times that of the northeast area,with obvious regional characteristics.(2)In the Yangtze River basin,the change of longitude in the east-west direction has no direct impact on the cultivation amount of A.flavus per gram of soil.(3)In the east coast,the A.flavus cultivated per gram of soil increased first and then decreased with the increase of latitude from south to north.(4)A.flavus can be isolated in the soil samples above 1000 m.Field pollution is an important source of aflatoxin contamination in peanut.The study on the distribution of A.flavus in soil in China could provide theoretical support for the early warning and prevention and control measures of aflatoxin contamination in peanut.