Study On The Controlling Effectiveness Of Mold In Stored Grain By Different Treatment Modes

Mould activities can deteriorate the quality of stored grain,and cause food safety problem.Effective measures must be timely taken to prevent mould activities in stored grain.The controlling technologies of mold activity in stored grain mainly include mechanical ventilation and fungicide treatment.Each controlling strategy has its own advantage to prevent or control the risk of mold in the management of grain storage.In practice,several factors including processing mode,dosage,environmental conditions and grain characteristics would affect the effectiveness and cost of grain management.Therefore,investigation on prevention strategy of grain mildew and elucidating the relationship between various processing parameters and actual effectiveness is of great importance for the scientific management of grain storage.This study mainly explored the relationship between mechanical ventilation parameters and mold activities in stored grain,and revealed the correlation between the fumigation treatment of high-efficient and low-toxic fungicide and antifungal effectiveness,which would provides theoretical basis and technical support for safe storage of grain.The ventilation test shows that there is a peak value between the unit ventilation volume and the antibacterial effect.When the ventilation volume reached 1.04 m~3/kg/d,it can effectively inhibit the growth of mold,and F reaches the maximum.Continuous increase of ventilation rate has no significant effect on the change of mould number in grain(P>0.05).The initial time of high-moisture grain ventilation had a significant impact on the ventilation effect,under the same effective ventilation volume(1.04 m~3/kg/d),the number of fungi in the timely ventilation group did not increase significantly after ventilation treatment.In contrast,the number of fungi carried by delaying 4 days and 6 days ventilation groups increased by 24 times and 249 times,respectively.The intermittent ventilation mode and the slow ventilation mode can improve the antibacterial effect of ventilation.Under the same treatment conditions,the final number of fungi in the grain is 1.46 times and 2.40 times lower than that of continuous ventilation mode and rapid ventilation mode,respectively.Compared with push-in ventilation,the suction ventilation can precipitate faster and inhibit the growth of mold more effectively.The distance between the vent and mold has a significant impact on the ventilation effect,and the antibacterial effect can be significantly reduced by 9.34/0-17.98%when the distance increases by 1 m.Without increasing the ventilation volume,deviating from the position of ventilation vent can not effectively control the hazards of high-risk molds such as Aspergillus flavus.The verification of ventilation effect of real warehouse with grain pile height greater than 6 m shows that the wind speed variation law of real warehouse is consistent with that of simulated warehouse,which indicates that the ventilation law of the simulated warehouse test is suitable for real warehouse.The antibacterial effects of three chemical agents were compared by using the plate fumigation method,and the results showed that the MIC of n-hexanal was 4-14 times and3.2-10.4 times lower than that of propionic acid and n-hexanol,respectively,and the MFC was 4-7 times and 3-6.5 times lower,respectively.A similar rule was obtained in that fumigation experiment of high-moisture grain in airtight containers.The minimal inhibitory concentration of n-hexanal on natural molds in 15%and 17%moisture grains is 8.14-16.28times lower than that of propionic acid and n-hexanol,respectively.Fumigation treatment has no obvious effect on MDA and FAV of wheat grain,which can reflect the changes of wheat quality.The fumigation concentration of 1.66 mmol/L did not affect wheat physiological indicators,such as germination potential and germination rate,which indicated that n-hexanal is a effective antifungal agent for grain management.The fumigation mode and fumigation conditions have significant effect on the treatment effect of n-hexanal.A variety of n-hexanal concentrations were selected to fumigate high-moisture grain,and the results show that the antibacterial effect of circulation fumigation is 2.80%-10.61%higher than that of natural volatile fumigation.The grain moisture,the status of mold activity,the distance between the input point of fumigation gas and the mildew point,and the initial fumigation time have significant(P<0.05)or extremely significant(P<0.01)effects on the fumigation effectiveness.The relationship between the influence of various ventilation parameters of stored grain on the actual ventilation effect and the influence on the mold activity was established through the research of this subject,and a high-efficiency and low-toxic mold inhibitor chemical agent with fumigation characteristics was screened,and the rapid inhibition and killing effect of the chemical agent on mold in grain storage under various required treatment modes was explored.The developed mode of partial ventilation and chemical agent treatment for grain storage has the advantages of high certainty of effect,low cost and strong application flexibility.It can provide an effective technical solution to prevent or control grain storage mold hazards and improve the emergency treatment level of grain storage mold.