Changes Of Microbial Diversity And Control Of Microorganims From Wheat And Corn During Storage

The species and abundance of microorganisms of grain influence quality and safety ofcereal products directly. Thus, it’s significant to know the microbial diversity of grain. In mypaper, the raw materials were wheat and corn. The functional diversity and the microbialdiversity of the grain were analyzed using BIOLOG technology and T-RFLP technology. Inorder to research the changing pattern of total microbial abundance during storage, the wheatwas treated by the antimicrobial agents and studied on the Fungal Diversity of Maize underdifferent storage conditions. The results showed that:1. The composition of the mold in the internal and external surface of the wheat was analyzedby using microscopy and colony morphology. The internal molds of wheat wereTrichothecium, Penicillium, Aspergillus; the external of the wheat were Trichosporon,Fusarium equiseti, Trichoderma, Cehalosporium, Aternaria, Aspergillus.2. The corn of10.04%,14.72%and19.46%three moisture contents were studied, Penicillium,Aspergillus, Rhizopus and Fusarium were the dominat species. When the moisture contentwas10.04%, Penicillium, Aspergillus, Fusarium and Rhizopus were the dominat species;when the moisture content was14.72%%, Penicillium, Aspergillus, Fusarium were thedominat species; while in maize of19.41%moisture content, Aspergillus glaucus andAspergillus flavus were dominant.3. Tirty two different species of bacteria were isolated and analyzed by restriction fragmentlength polymorphism analysis (ADRDA) combined with molecular identification andbiochemical experiments. The results showed that, the representative types of Bacillus on thewheat were mainly Bacillusbrevis, B.licheniformis, Bacillus sp, B. amyloliquefaciens, Bacillussp.4. The microbial functional diversity which in different varities of wheat was analyzed byusing BIOLOG. It showed that the microorganisms of wheat using thecarbon source hadupward trend with the increase of culturing time. Meanwhile, the microorganisms of wheat indifferent wheat had significant difference in utilization of carbon sources. The utilization ofsix carbon sources was increasing with time.5. The analysis of the diversity index, evenness and similarity indices of bacterial flora viaterminal restriction fragment length polymorphism (T-RFLP) technique in different varities ofwheat showed that, the comparison of bacterial sequence length and Ribosomal Database Project II database showed that there were nine bacterial species in the different areas ofwheat. They were Clostridium sp, Arthrobacte, Bacillus cereus, Bacillus sphaericus,Corynebacterium genitalium, Pasteurella, Bacillus subtilis, Pseudomonas, Escherichia coli.6. Greater diversity and lower dominance index were presented in maize with smallermoisture content and lower temperature, while lower diversity and larger dominance indexdemonstrated in high moisture content maize. Moisture content and temperature hadsignificant effect on the amount of fatty acid values, the higher moisture content andtemperature were, the higher the amount of fatty acid value was.7. The treatment of four antimicrobial agents, Natamycin,2-aminobutane, potassium sorbateand Nisin, on the different varities of wheat during the storage of35d was studied in thispaper. With the increase of storage time, the moisture content of wheat increased and thendeclined, the total number of Bacillus.spp colonies decreased, finally, it was stable; The totalnumber of fungal colonies increased, The amount of fatty acids and the total acidity valueswere significantly positively correlated with fungal abundance and significantly negativelycorrelated with Bacillus.spp abundance. The condition of the precipitation value was oppositeto that of the amount of fatty acids and the total acidity values.