2. The first-class quality standard of national standard of corn: impurities should be less than or equal to 1%, bulk density (g/l) should be greater than or equal to 7 10, crude protein (dry basis) should be greater than or equal to 10%, imperfect particle size should be less than or equal to 5%, and moldy particles should be less than or equal to 2%.
3. Three-level quality standard of corn: impurities should be less than or equal to 65438 0%, bulk density (g/l) should be greater than or equal to 660, and crude protein (dry basis) should be greater than or equal to 8%; Imperfect particles are less than or equal to 8% and moldy particles are less than or equal to 2%.
Extended data
Adjust the requirements of imperfect particle size limit. According to the analysis of the quality investigation results of stored and stored corn in recent years and the measured data provided by relevant units, considering the influence of mechanical harvesting, threshing and drying on the imperfect grains of commercial corn, and referring to the main national standards of corn production, the maximum limit index of imperfect grains was adjusted from 5.0% regardless of grades to 1-5 ≤4%, ≤6%, ≤8% and ≤ 65435 respectively.
The supplement of bulk density of high moisture corn was cancelled, and the operation specification of rapid precipitation was standardized. A large number of experimental results show that the bulk density of high moisture corn changes irregularly after precipitation (natural drying and drying in drying tower). The original standard stipulated that the bulk density of corn with water content greater than 18.0% was different from the actual test results, especially for corn with water content over 23%.
In the new standard, the technical conditions and operation methods of corn quick drying and precipitation equipment are added. It is stipulated that for corn with water content greater than 65,438+08%, the water content of corn should be reduced to below 65,438+08% in the laboratory with quick drying and precipitation equipment, and the bulk density should be determined after the corn sample is cooled to room temperature.
Increased the requirements for label identification. In order to strengthen the traceability of commercial corn and satisfy consumers' right to know, the new standard increases the requirements for labeling and the provisions for genetically modified labeling.
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