Core production process and quality control points for high-temperature sterilization and vacuum sealing of canned food

Canned food can be stored at room temperature for a long time, relying on two core production processes: standardized high-temperature sterilization and vacuum sealing. Minor deviations in process parameters can directly cause the finished product to swell, deteriorate, and shorten its shelf life, which is also a core control node in the factory's quality control process.

Canned food can be stored at room temperature for a long time, relying on two core production processes: standardized high-temperature sterilization and vacuum sealing. Minor deviations in process parameters can directly cause the finished product to swell, deteriorate, and shorten its shelf life, which is also a core control node in the factory's quality control process. Taking the production process of canned mushrooms as an example, fresh mushroom raw materials are first classified, impurity removed, and pre boiled in boiling water to shape. Then, they are quickly loaded into metal cans, injected with mixed saltwater soup, and sent to vacuum sealing equipment to extract air from the cans, complete the sealing, and then sent to a high-temperature sterilization kettle. The sterilization temperature and duration are adjusted according to the size of the can and the variety of mushrooms. The conventional sterilization temperature for whole canned mushrooms is maintained at 121 ℃, and constant temperature sterilization is carried out for 25 to 40 minutes to completely kill high-risk pathogenic bacteria such as Clostridium botulinum and mold. After sterilization is completed, the temperature is slowly lowered in sections to avoid deformation and weld leakage caused by excessive temperature difference in the cans.
The control of the vacuum sealing process directly determines the stability of canned food storage. The vacuum degree of the sealing equipment needs to be stably controlled within the range of 0.04 to 0.06 MPa. If the vacuum degree is insufficient, residual air in the can may oxidize and discolor the food during storage, and the soup may become cloudy. Long term sea transportation in high-temperature environments can easily lead to tank swelling and waste reporting; If the vacuum is too high, the metal can body will be compressed and dented, affecting the appearance of terminal supermarkets. The quality control workshop will sample and test the sealing of sealed cans every hour, using a water bath bubble test. The sealed cans will be immersed in high-pressure water to observe whether bubbles are generated at the seams of the cans. Once a leak occurs, all batches will be reworked and repackaged to prevent defective products from entering the storage and export process. Raw material pretreatment is a quality key point that is easily overlooked. Fresh mushrooms come with soil and microbial spores, and the cleaning process needs to be divided into three steps: rinsing with clean water and high-pressure spraying. Some high pesticide residue raw materials also need to be soaked in fruit and vegetable specific cleaning agents. The raw materials are strictly classified according to size and specifications to ensure that the ingredients in the same tank are evenly distributed and meet the standardized sales requirements of overseas supermarkets.
The sterilization process parameters for different types of canned food are completely distinguished. Fruit canned food has high acidity and low difficulty in microbial survival. The sterilization temperature can be lowered to 90 to 100 ℃; Canned seafood has a high protein content and is prone to breeding pathogenic bacteria. The sterilization time is twice as long as canned mushroom; Canned bean starch is prone to bloating, so it is necessary to adjust the pH of the soup and maintain a constant temperature for a long time to sterilize. The finished product storage process continues to assist in quality control. The temperature of the canned goods storage environment needs to be stably controlled below 25 ℃ to avoid long-term exposure to high temperatures. The temperature inside the sea freight container can reach over 50 ℃ in summer. Therefore, it is necessary to cool down and store the goods in advance before export packing, and use insulated pallets to reduce the loss of sealing performance caused by high temperatures. The common quality accidents in the industry are mostly caused by lax process control: temperature fluctuations in sterilization kettles, irregular calibration of sealing equipment, simplified raw material cleaning processes, and large quantities of defective products being shipped out. Overseas distributors return the entire container, and the factory bears the full sea freight, cargo loss, and customer liquidated damages, resulting in huge losses. Therefore, mature canning processing plants will set up independent craft control teams to monitor various parameters of the production line 24 hours a day, retain process records for each batch to achieve full traceability.