Packaging and antisepsis of the hottest fresh food

Packaging and antisepsis of fresh food

fresh fish and shellfish

fresh fish and shellfish are mostly packed with films with good flexibility such as vinyl chloride, polybutadiene, polyethylene and polystyrene after being packed, and high-grade shrimp and scallops are packed in foamed polystyrene containers and sealed with saliwell/EVA films; Fresh fish, such as sardine and saury, are packaged with vinyl chloride extended film. The fresh fish of Japanese fisheries companies use a low temperature of 3 ℃ ~ 5 ℃ from packaging, circulation to consumption. Fresh fish in the United States are put into plastic bags, pumped hollow in the process of operating the universal experimental machine, replaced with carbon dioxide, and sold in the state of freezing for the factory. Alaska company will remove the head and viscera of salmon, put it into polyvinylidene chloride as the core layer, with good air tightness plastic film bag, fill it with 90% carbon dioxide packaging, and store it at 0 ℃ ~ 2 ℃, the freshness of fish is good. The so-called "incomplete quick freezing method" is used for the storage of fresh fish, that is, the fish is packed in nylon and polyethylene composite film, vacuum packed, and preserved at - 3 ℃. Compared with ice storage, the freshness is good, and the meat tissue does not collapse. Fresh fish with the above packaging can prevent water evaporation and bacterial re pollution, and low-temperature circulation can ensure commercial sterility

fresh meat

when fresh meat packaged for consumption is stored at low temperature, due to the growth of the psychrophilic bacterium Achromobacter, colonies are produced on the surface of meat, forming rancidity. The quality of fresh meat decreases, Lactobacillus makes the meat green, and Bacillus subtilis, Bacillus potato, etc. make the meat corrupt. The packaging materials for meat consumption (users) use OPS (extended polystyrene) and hips (impact resistant polystyrene) as pallets, and extended vinyl chloride film as outer packaging materials. The same insulation material often appears at 10 ℃, which can be stored for 3 ~ 4 days, and the packaging process is fully automated

in order to prolong the storage life of meat, inflatable packaging is used. After slaughtering, the cattle are treated at low temperature, cut according to the specifications, and the meat temperature is below 5 ℃. Put it into a PVC/PE container, replace the air in the container with a mixture of oxygen and carbon dioxide, and then use polyvinylidene chloride as a barrier, cover and seal it. Oxygen combines with beef myoglobin to produce oxidized myoglobin to maintain the unique bright red of beef. Carbon dioxide combines with water in meat to produce carbonic acid, reduce pH value and inhibit bacterial growth. For meat packed with gas, 2 ℃ ~ 3 ℃ is the best

chilled beef

chilled beef is sliced at the place of origin, vacuum packed in airtight packaging materials, and sent to the market for supply. The purpose of making leg meat into chilled meat is to ripen and clean it after packaging, prevent the surface of the meat from drying and natural loss, prevent light and oxygen from producing meat color changes, inhibit microbial growth, and maintain freshness for a long time

the packaging materials of chilled beef are pressed with multi-layer plastic films. The shrinkage types include PE/NY/Eve film, NY/EVA film, NY/10nomer film, NY/PE/EVA film, NY/10nomer/EVA film, NY/PE film and NY/10nomer/PE film

in order to reduce the number of bacteria before vacuum packaging and in the processing environment, the United States disinfects meat factories with iodine and other fungicides after cleaning machinery and appliances with pulp detergent

fresh fruits and their products will suffer from various impacts or friction in different environments. Vegetables such as tomatoes and lettuce and fruits such as apples and grapes are mostly packed in plastic. Fruits and vegetables are heated due to the promotion of biochemical reactions by respiration, withered due to the evaporation of water, resulting in softening of tissues and corruption due to the growth and development of bacteria and molds. In order to prevent the vegetables from spoiling, the packaged vegetables should not carry soil. Lettuce and other vegetables are pre cooled and packed with polyethylene film. They can be preserved for 30 days at 0 ℃ ~ 2 ℃. Soft vegetables are packed in polyethylene bags with a thickness of 0.03 ~ 0.5mm. Cucumber and other vegetables are packed with soft vinyl chloride film and then heat shrinkable. Tomatoes and potatoes are packed with soft vinyl chloride, EVA and polybutadiene film

apples and other apples are stored at low temperature with 3% - 5% oxygen and 3% - 5% carbon dioxide (i.e. air control method). Apples stored by this method are put into corrugated boxes lined with polyethylene film, and sealed with deoxidizer to reduce oxygen concentration, which can be preserved for a long time without quality degradation. Fruits volatilize volatile substances such as ethylene and acetaldehyde during storage, thus ripening rapidly. In order to delay ripening and maintain freshness, fruits are sold in plastic bags together with activated carbon and diatomite that can adsorb ethylene gas. (Note: PE: Polyethylene PS: Polystyrene PVC: polyvinyl chloride PP: Polypropylene EVA: ethylene, acetic acid, ethylene copolymer PVDC: polyvinylidene chloride NY: Nylon ionomer: resin name)

source: Food Zhou Xiuqin