Remote Monitoring And Early Warning Of Fungus In Granary

Grain is very vulnerable to microbial infection during storage.Early monitoring and early warning of microbial activities in grain storage is an important technology to ensure food security.This topic mainly studies the remote monitoring and early warning of fungal activities in grain storage,and provides new technical means for early prevention and control of fungal hazards in grain storage.In this paper,a remote monitoring system for fungal activities in grain storage is constructed,which consists of three parts:gas sampling,granary detection and remote control.In the gas acquisition part,a low-flow miniature gas pump is selected to eliminate the influence of sampling on CO₂ concentration of monitoring points.The gas pipe adopts a thin tube made of silica material.The material gas pipe has the characteristics of resistance to bending,deformation resistance,gas transmission stability,gas transmission stability,which can improve the detection response speed of the gas sensor and reduce the impact of long and thin gas pipelines on the detection process and test results.Through the monitoring and application test of the real warehouse grain storage,the operation module of grain condition monitoring,parameter setting,data query,data output,real-time display of detection data,alarm and so on,which can realize the application functions of remote detection control,detection programming and result presentation of stored grain fungus hazard detection.In the parameter monitoring experiments carried out in this project,the monitoring system can achieve the effect of monitoring fungal activities in grain storage in real warehouse.The detection effect and influencing factors of stored grain mildew were analyzed under the condition of real warehouse.The results show that the monitoring efficiency can be improved and the reliability of the monitoring results can be guaranteed by controlling the gas sampling velocity of the monitor from 50mL/min to 100mL/min.The theoretical gas sampling volume was set at 1.5 times the internal volume of the gas pipeline can meet the needs of different specifications of gas pipeline for detecting microbial activities in stored grain.The difference of stored grain temperature not only affects the gas production rate of fungi,but also affects the detection effect.At different storage temperatures,the change trend of CO₂ concentration in the grain reactor was consistent with that of the amount of bacteria in the grain,and the correlation coefficient between the two was greater than 0.99,indicating that the development of stored grain mold was completely synchronous with the generation of CO₂ gas.Under the condition of considerable quantity of pathogen of 30?higher than20?condition detection of CO₂ value 4.7 times,shows that temperature change can affect the test results,under the condition of low temperature grain storage of elevated CO₂concentration more attention should be paid.The difference of CO₂ monitoring of grain species was studied.Monitoring the CO₂concentration of wheat and rice with the same water activity showed that the CO₂ gas yield of rice was 2.04 times higher than that of wheat.At the same time,the influence of grain varieties on CO₂ gas diffusion was also obvious.When the CO₂ gas concentration of mildew source was similar,the maximum CO₂ concentration at 0.5 m in the rice stack was 50%higher than that of wheat,and the peak time of CO₂ concentration could be 4 days earlier.The simulated storage remote monitoring test was carried out on the extreme bad storage state of water leakage in grain depot.The results showed that the monitoring results of CO₂concentration were in good agreement with the change of water increasing rate of grain bulk?r>0.99?during the 8-day test period.Sensory examination can clearly distinguish the discoloration and odor of different degrees in the lower layer of grain pile after 8 days storage period.However,the number of fungi detected by the classical fungi culture analysis method increased from 10*10² cfu/g to 200*10² cfu/g after 8 days.It is difficult to judge the change of grain quality and the mildew status.It shows that the remote monitoring of this experiment has obvious advantages in ensuring the stability of grain storage and avoiding the harm of fungi.Through the comparison of the remote CO₂ gas detection results of grain piles with the changes of grain quality and the number of grain mold changes,excluding the influence of insect activity in the grain storage,a monitoring point of CO₂ gas concentration with 2 m interval was set up in the uncovered grain stack.The concentration of CO₂ gas was more than0.1%at any point.The probability of mold partial activity in the grain stack could be determined to be more than 99%,and the early warning signal of fungal hazards in stored grain could be sent out.Aiming at the ventilation and Insecticidal fumigation technology of grain stack commonly used in conventional grain storage,the effect of remote monitoring system was studied.The results showed that the ventilation of grain stack had a significant inhibitory effect on fungal activity,and the final inhibitory effect was consistent with the decrease rate of grain moisture and the change value of CO₂ gas concentration;The effect of phosphine fumigation on fungal activities in grain stockpiles was not obvious.Only the opening of storage doors and human activities could affect the monitoring value of CO₂ gas concentration.After 3 days of fumigation,the CO₂ gas concentration produced by mildew point could be restored to its original state.Therefore,the remote monitoring system established in this experiment can still be used as an effective method for monitoring fungal activities in grain storage when the barn is not suitable for the detection operation of personnel entering the barn.