Quick frozen corn wholesale blanching: threshed corn kernels should be blanched immediately, using boiling water steam. Boiling water blanching generally uses sandwich pot, steam blanching can be carried out by steamer. The heating temperature is 95 ℃ to 100 ℃, the blanching time is about 5 minutes. Cooling: the corn kernels after blanching should be cooled immediately, otherwise the product quality will be affected. Generally, the method of sectional cooling is adopted. Firstly, the temperature of corn kernels at 90 ℃ is reduced to 25 ℃ to 30 ℃ by cold water spray method, then the temperature in the center of corn kernels is reduced to below 5 ℃ by soaking in water of 0 ℃ to 5 ℃. Selection: timely manually pick out the cob chips, silk, discolored grains other impurities, so as to reduce the pressure of screening before packaging ensure the product quality. Quick freezing: fluidized bed tunnel is used for quick freezing of corn kernels. The corn grain is laid on the conveyor belt, the fans under the belt blow up the cold wind at the speed of 6-8 M / s to make the corn grain in suspension. The evaporation temperature of the machine is - 34 ℃ to - 40 ℃, the cold air temperature is - 26 ℃ to - 30 ℃, the thickness of corn kernels is 30-38 mm. Freezing for 3-5 minutes can make the central temperature of corn kernel reach - 18 ℃. The frozen corn kernels should adhere to each other the surface should be free of frost. Screening: the impurities, defective grains broken grains should be further removed the frozen corn kernels. If necessary, a 0.4cm sieve can be used for screening. Packaging: quick frozen corn kernels should be packed at - 6 ℃. It is generally packed in polyethylene plastic bags, 250 g / bag 500 g / bag as required. After packing, seal print the date of production on the seal, send to the cold storage immediately after packing. Cold storage: the temperature of cold storage should be below - 18 ℃, the relative humidity should be 95-98%. The temperature fluctuation range in the cold storage should exceed ± 2 ℃. There should be enough space between stacks to facilitate air circulation uniform stable storage temperature. 4、 Quality standard (1) sensory index. Color: light yellow golden yellow; shape: uniform grain size, no broken grains, neat incision; impurities: no filaments, bracts other impurities; no frost phenomenon in the package; taste taste: taste after boiling for 3-5 minutes, it should have the unique taste sweet taste of the sweet corn variety, crisp refreshing. (2) health indicators. Copper is less than equal to 5.0 mg / kg, arsenic is less than equal to 0.5 mg / kg, lead is less than equal to 1.0 mg / kg. Microorganisms meet the requirements of commercial sterility.