The Studies On Monitoring Mold Activity Of Storaged Grain With Gas Sensor

CO2 detection technology is developed in recent years, which is a very potential microbial detection method in grain storage. It can detect the microbial activity with the same way as the grain temperature detection by combining modern electronic sensing technology and specific facilities. In addition, CO2 detection technology provides more information, higher detection sensitivity. Existing reports are mainly about the simple relationship between the amount of the CO2 concentration and the mold quantity in grain heap. As molds'damage is big different in different physiological states to grain and molds may produce mycotoxins and other secondary metabolites in propagating body forming state. So researching the feature of molds release CO2 when the molds'physiology state change, which contribute to evaluate the degree of risk of grain storage.The molds'physiology condition can be divided into such three states as spore state, hypha growing state and propagating body forming state through the microscope. The correlation of different physiologic state of mold and CO2 concentration in grain heap was studied. The result showed that there was significant difference of the CO2 concentration in grain heap under different physiologic state of mold. When the mold was in the state of spore, the change of the CO2 concentration was very little, generally no more than 0.1%/d. The CO2 concentration increased a lot during the state of hypha growing. Its average increase rate was 10 times of that of spore. The increase of it lasted in the state of propagating body forming. But the increase rate declined significantly. At that time, the increase rate of CO2 concentration in grain heap was only about 30% of that during the state of hypha. The CO2 concentration change just as the letter"s"in the growth cycle of mold .the test result show the breath strength of grain was steady, and at the same time far less than that of mold in same moisture. So the physiologic state of mold can be defined through detecting the change of CO2 concentration online outside the storehouse.By comparing the correlation of CO2 concentration in grain heap and the grain quality, it was found that the relative modulus between the change of CO2 concentration in grain heap and the fatty acid of corn amounted to 0.98. Moreover, it showed the detection of the change of CO2 concentration in grain heap was more forward-looking than the quality of the grain. When the CO2 concentration in the wheat heap and that of in the paddy heap displayed obvious changes, the viscosity of the wheat and the fatty acid of the paddy did not show any apparent varies. By comparing the correlation of the CO2 concentration in the grain heap, the corn heap, the paddy heap and their microbial activity, the results show that the correlation coefficients respectively amounted to 0.98, 0.99, and 0.97. It had been proved that the microbial activity method could determine the physiological status of mold exactly and measure the degree of risk in stored grain. Therefore, detecting the microbial activities of storage cereals by CO2 detection technology, not only to achieve the same effect of microbial activity method, but also to have the advantages of automation and remote control testing...