After more than 30 years of development, my country’s plastic food packaging industry has become an indispensable industry in the national economy. Although domestic and international public opinion has generally believed that plastic food packaging bags have various adverse effects on consumers’ health and the environment this year, they have continued to call for a large and extensive use of paper food packaging bags. However, the consumption of plastic food packaging materials is still increasing rapidly.
The original intention of developing plastic food packaging materials is to solve the problems of various types of food that are easily damp, moldy, and deteriorated due to no packaging or poor packaging. However, due to some reasons, consumers often smell food when they open food packaging bags. The strange smell or even odor in the packaging bag has caused many conflicts and disputes between consumers and food factories, food factories and packaging factories, and packaging factories and raw material suppliers.
1. Production packaging material stage
In the production stage of packaging materials, printing, extrusion lamination, dry lamination and other processes will lead to the generation of “peculiar smell”. The specific performance is as follows:
(1) Residual solvent problem
In the gravure printing and solvent-based dry compounding process of plastic composite materials, a large amount of organic solvents, such as toluene, ethyl acetate, butanone, etc., need to be used. According to the process requirements, these solvents should be volatilized in the production process, but in the actual production process, there will always be more or less solvents that are not completely volatilized due to various reasons, which is the so-called “residual solvent”, ” “Residual solvent” is generally a mixture of several solvents. When the content of “residual solvent” is lower than a certain value, the human sense of smell will not sense its existence, and it will not affect the taste of the packaged food. When the content of “residual solvent” is greater than a certain value, people’s sense of smell can sense its existence. When consumers open the food packaging bag with high “residual solvent”, they may smell different from the moldy food. , rotten “odor”.
(2) The problem of resin oxidation odor
Extrusion lamination is another compounding process for compounding flexible packaging materials. In this process, the granular plastic resin needs to be melted at high temperature, coated on other substrates through a die, and then cooled to form. If the temperature is too high, the plastic resin will be oxidized and decomposed, resulting in the so-called “resin oxidation odor”. If food is packaged with this material, the aroma of the food will also change. This “peculiar smell” can be produced through strict control. Process conditions are eliminated.
2. Food packaging stage
Other flavors in the production workshop will be mixed into the packaging, especially some inflatable packaged foods, such as potato chips, egg yolk pie, etc. According to normal requirements, the inflatable packaged food should be filled with bottled spring nitrogen or nitrogen and carbon dioxide. gas mixture. However, in order to reduce production costs, many enterprises charge ordinary air, and in order to reduce the impact of the noise of the air compressor on the operation work, the air compressor is generally placed far away from the packaging production line, so that other areas are inevitably placed. of other flavors of air into the food packaging. Whether it is legal to fill with air or not, it is self-evident that the oxygen in it will cause the oxidation of certain ingredients in the food.
Unsatisfactory process conditions such as temperature and time used for processing will also lead to the generation of “peculiar smell”. In order to prolong the shelf life of food, after the packaging process is completed, the packaged food should be sterilized, boiled in water below 100°C, cooked at high temperature of 121°C and 135°C, sterilized by microwave oven, radioactive radiation, etc. The above-mentioned sterilization methods all require a certain temperature or intensity for a certain period of time to achieve the predetermined sterilization effect, and the sterilization conditions need to be adjusted according to the weight and volume of the content. Generally, the common problems in the post-processing process are mainly that the high-temperature cooking equipment does not meet the requirements; not paying attention to the hygienic conditions of food processing in the early stage and blindly emphasizing the sterilization conditions in the later stage, resulting in unstable product quality.
3. Transportation and storage of packaged food
The conditions of transportation and storage are relatively poor, mechanical collisions are prone to occur between food packaging bags, and the food packaging bags are under too much pressure. High, which promotes the rapid reproduction of bacteria in the contents that have not been strictly sterilized, and the physical deterioration, which leads to the expansion of the bag; the poor selection of packaging materials, air resistance, moisture resistance, and insufficient shading, cannot effectively protect the contents, causing the contents Loss of the original fragrance, dampness, discoloration; poor packaging technology, resulting in loose sealing or damage to the sealing, resulting in the leakage of the inner gas and the outer air and the entry of external air and bacteria into the interior of the food packaging bag. Packaged foods are not sold or consumed in a timely manner, resulting in past expiration dates.
The researchers found that the so-called “peculiar smell” of packaged food has many manifestations, and the reasons for the “peculiar smell” are also various, which may lead to the occurrence of “peculiar smell” in all aspects of food production, transportation, storage, sales and consumption. Ultimately, the products produced cannot realize their value, causing waste of social resources, or causing harm to consumers’ physical and mental health.
The problem of “peculiar smell” of packaged food is not only a problem of food producers, but a problem that should be paid attention to in all relevant links of the whole society. In addition, the relevant departments strengthen the management of enterprises, and eliminate the “peculiar smell” of packaged food from the source.