Curl "teeth" - cover hooks and hooks are not overlapped, V-shaped or protruding at the lower edge of the curl because of the sealing curve of a sealing wheel is not ideal, the pre-sealing machine or the head sealing roller is adjusted Too loose, the sealing wheel wears. The tight adjustment of the two sealing rollers will aggravate the defects of the teeth. The design of the can lid is not ideal. The can lid has wrinkles on the bearing surface. There is too much sealant in the curl or too much sealant in the lid. The tray pressure is too high. , Excessive amount of solid cans, sealing wheel bearings are not flexible and so on. ? Crimping - cracks in the outer layer of the seam at the seam of the can body. The reason is that the second sealing wheel is too tightly adjusted, the lid material is defective, the lid has too many seals, and the curl is trapped inside. The head sealing wheel is too tight, causing the lid to fold too long. The tightness does not meet the requirements due to an unreasonable curve of the sealing wheel, improper adjustment of the sealing wheel, serious wear of the sealing wheel curve, irrational shape of the rubber-bearing surface of the can lid, or wrinkles on the rubber surface of the can lid, and the bearing of the sealing wheel is not running. Flexible and so on. Hemming damage - The damage on the outer surface of the hemming part or the peeling off of the coating, due to the unreasonable curve of a sealing wheel, the low smoothness of the sealing surface of one or two sealing wheels or the tight adjustment of the wheel. ? (2) The reasons for the lax sealing of the glass bottle: The gap between the bottle turntable and the bottle holder is not uniform or the whole machine action is inconsistent and the bottle is broken.æ“ Twist the belt with the speed over the mouth of the ambassador to crush or the speed is too small to seal the bottle tightly. ? (3) The reason why the seal of the heat-sealing bag is not strong or the seal is burned or damaged is that the former is mainly due to the low sealing temperature or the insufficient sealing pressure and heat sealing time; the bag mouth has debris to make the sealing not secure; the heat sealer Bonding of the melted plastic; the shaper and the material do not center when making the bag, so that the edges of the bag seam are not aligned. The latter is mainly caused by the heat sealing time being too long or the temperature being too high or the pressure being too large. ? Sterilization process? The purpose of sterilizing canned food is to kill microorganisms that are detrimental to food and produce toxins. When sterilizing, it is necessary to preserve the original color, flavor, texture and nutritional value of the food. If the sterilization is not complete, the microorganisms in the cans will multiply when the conditions are suitable for growth, causing the food to be corrupted. ? Canned sterilization often uses heat sterilization - the product is heated to a certain temperature for a certain period of time to kill the bacteria. Most of the heat sources use steam or hot water. When sterilizing, each can must be in direct contact with the heat source. There are many factors that affect the bactericidal effect, mainly the following points: Improper canned sterilization formula (temperature or time can not meet the requirements); Steam sterilizing exhaust is not sufficient or the convection effect of hot water sterilization is not good, etc. With soup foods, too high a solids content can affect the convective heat transfer effect in the tank or the filling function in the tank is too full to make the head gap gas agitation function. If the initial temperature is too low, the time required for the can to reach the sterilization effect will be extended, making the sterilization formula inappropriate. The high temperature of canned sterilization will temporarily soften the bottom apron. When the inside of the can is cooled after the sterilization is completed, a small amount of cooling water may be sucked in, especially when the crimping quality is not good. The nature and chemical composition of foods are the environmental conditions for the presence of microorganisms during sterilization. The acids, sugars, proteins, oils, and salts of foods can affect the heat resistance of microorganisms. Other factors such as low ph value of the food, high salt concentration, and the presence of nitrites and organic acids can enhance the heat of sterilization. The high concentration of sugar liquid has a protective effect on bacterial spores, food block size, solids content, canning methods, etc. will affect the heat transfer within the tank. The microbial contamination in the tank during sterilization is high, and because the residual microbe in the tank after sterilization is proportional to the number of initial bacteria, after the same sterilization conditions, the bacteria content in the tank is high, and the remaining number is high, which will make the can not reach Commercial aseptic requirements. Cooling process After the canned food is sterilized, it must be cooled quickly. Otherwise, the food in the can still maintain a fairly high temperature and continue cooking. This will change the color and flavor of the product and sometimes affect the structure of the product. Normal-pressure sterilized can of tinplate can be directly put into cold water. When the temperature of the can is cooled to about 40°C, it is taken out. The residual heat inside the can is used to evaporate the moisture attached to the can. If the cooling is excessive, the moisture attached to the can is not easy to evaporate. In particular, moisture in the can seam is difficult to evaporate, which can easily lead to corrosion of iron skin or recontamination of microorganisms. Glass bottles and cans due to poor thermal conductivity, sterilization can not be directly put into cold water cooling, or easy to cause rupture, should be sub-cooling. Pressure-sterilized cans are sterilized. Because the food in the tank expands due to high temperature during sterilization, the pressure in the tank increases significantly. If the pressure is rapidly restored after sterilization, the internal pressure will be too large, which will cause deformation or rupture of the tank and affect the can. Sealing performance. Therefore, such cans should be pressurized and cooled, ie, back pressure cooling, so that the pressure in the sterilizer is slightly greater than the pressure in the tank. When the contents of the can are sufficiently cooled and the internal pressure is moderated, no expansion or rupture occurs. Pressurized cooling can use steam pressure cooling or use air pressure cooling or timely cold water into the sterilization pot cooling. ? After heat sterilization, it will still be re-contaminated by microorganisms suspended in canned cooling water or on conveyor belts and on unclean surfaces of handling equipment. Water is the main carrier for microorganisms to cross the leakage path of the packaging container seal or damaged structure. In the post-cooling stage, when the contents of the tank are cooled, the pressure inside the tank will drop to form a partial vacuum. When this occurs, there will be a chance of leakage if the water contains enough water. A quantity of microorganisms can also cause re-contamination. ? The main reasons are: Structural defects - Deformation and damage to the cans caused by incorrectly sealed structures or over-mechanized handling damage the integrity of the cans. During the cooling process, the cooling water is not clean and the micro-organisms in the can seams enter the tank. It causes re-contamination. The main cause of can damage is impact or pressure. When the can speed on the conveyor belt is slowed or the conveying direction changes, it will impact the can because it collides with other cans or other parts on the conveyor belt. When transported on a conveyor, its forward movement is hindered while the conveyor belt is still moving and the cans are squeezed and damaged. ? In order to ensure the quality of canned food and protect the health of the people, they must follow the rules during the packaging process, storage and transportation process to avoid corruption during the storage of canned food. Golden Round Chafing Dish,Chafing Dish With Glass,Stainless Steel Chafing Dish,Oblong Chafing Dish Shaoxing Biaoyi Hardware Products Co., Ltd. , https://www.byeob.com
A closer look at canned food packaging processes (below)