Analysis and detection of the correlation between food packaging and food shelf life
Abstract: It is the most important goal of packaging to ensure the quality of food during the shelf life. There are no standard requirements for how food packaging materials should be selected and what conditions should be met. This article will discuss the relevance of food packaging and food shelf life from the key factors affecting food safety.
Keywords: shelf life, transmittance, food, microbes, carbonated drinks
Food safety is currently the focus of most attention. With the continuous exposure of “returning milkâ€, deterioration of food quality, and date of production of bulk foods, the issue of food shelf life has become the focus of the people, and the most important protection of soft packaging as a food has its shelf life. What kind of association has also received widespread attention. This article will discuss the relevance of food packaging and food shelf life from the key factors affecting food safety.
Food shelf life
At present, for most foods, the shelf life of food is set by the company itself, and there is no mandatory regulation in the country. Due to the shortage of technology and equipment, some enterprises do have experience and “hair estimation†when determining the shelf life. For more enterprises, how to uniformly and reasonably determine the shelf life and shelf life of food is also a technical problem.
Physical and chemical indicators, health indicators and sensory indicators are the three main aspects for assessing whether foods are degraded. Physical and chemical indicators stipulate the content of ingredients that foods should reach. Health indicators measure the degree of microbial or other contamination of foods, while sensory indicators determine food quality. Or a basis for good or bad taste. For different foods, the basis for assessment is different. For example, nutrition refers to ingredients, and specialty products value flavor. However, if the health indicators are not qualified, it is directly related to food safety.
In 2006, the National Light Industry Bureau made clear provisions on the shelf life of nine types of foods. Unfortunately, the practicality of this regulation is not high. For example, the shelf life of PET bottled carbonated beverages is not marked as 12 months, which is the specified shelf life. 2 times. Food industry standards and national standards also lack methods for determining the shelf life of foods, although some of the early versions of the standards mention food shelf life, such as GB/T 10792-1995 carbonated drinks (soda), but the practicality is very poor, so This content has been removed in the latest 2008 revision standard.
The current food shelf life has the following three problems: The first is how to determine the shelf life of the food, and the actual test by accelerated test is not affordable for the average SME in the cost and detection cycle, and there is no uniform test method at present. . Second, the difference between the shelf life and the shelf life, the shelf life is the guarantee that the manufacturer makes to the consumer, to ensure that the quality of the food is the best during the marked time, and the food that exceeds the shelf life can still be eaten if the color, fragrance and taste are not changed. The shelf life refers to the final date when the food is edible under the conditions indicated, and beyond this period, the food will deteriorate. There are very few manufacturers that actually label the shelf life, and the focus of our attention is not whether the food has the best quality during the shelf life but whether the food has deteriorated. Third, the development and application of new packaging materials, taking milk powder as an example, the provisions of the National Light Industry Bureau in 2006 that the tinplate barrels have a shelf life of one year and plastic bags for three months, but in fact we bought them in supermarkets. The shelf life of bagged milk powder is mostly more than 6 months. There are many kinds of plastics. If the bag is made of PE material, it may deteriorate in less than 1 month, and the use of aluminum-plastic composite bag can extend the shelf life to 1 year.
2. The relationship between flexible packaging and shelf life
2.1 The main reason for food spoilage
For most foods, the main cause of deterioration is the growth of microorganisms. Cleaning, disinfection and sterilization in the food processing process, as well as baking, frying and other processes can significantly reduce the types and quantities of microorganisms in food, or even completely kill, but the physical and chemical state of food raw materials, the processing methods of food processing, raw materials Differences in the degree of microbial contamination can affect the microbial residual rate in processed foods. Moreover, the processed food may also be re-contaminated by microorganisms during processing, transportation and storage. The remaining microorganisms and re-contaminated microorganisms in the processed food may still germinate when conditions are suitable, causing spoilage of the food.
Temperature, gas, humidity and other factors are closely related to the growth and reproduction of microorganisms in food. When the food is actually stored, the temperature and humidity are controllable and the cost is not high, but it is difficult to control the gas content in the environment. If there is sufficient oxygen in the food environment, it is beneficial to the growth of aerobic microorganisms. Because the growth rate of aerobic microorganisms is much faster than that of anaerobic microorganisms, the food spoilage is much faster than that of anaerobic microorganisms. It can be seen that oxygen is an important factor leading to deterioration of food.
2.2 Analysis of the causes of food deterioration during the warranty period
In addition to the very low reference shelf life that some small manufacturers have obtained through “hair estimationâ€, reports of deterioration of some large factories and even famous brands of food during the shelf life have also appeared frequently. Deterioration of food during the shelf life can have quite serious consequences, but most manufacturers attribute the deterioration of foods that appear in the shelf life to packaging leaks caused by improper handling in transportation and storage. Since most of these food deterioration events are ultimately unsuccessful due to the lack of authoritative test results, it is impossible to determine whether the deterioration is due to the presence of packaging leaks. If the packaging of the degraded food does not leak, and the food completely meets the process requirements before packaging, the packaging has problems, and the problem may exist in the structural design of the packaging, and is more likely to appear in the selection of materials.
2.3 Correlation between the barrier properties of packaging materials and the shelf life of food
Based on the above analysis, it can be seen that there is a close relationship between the overall oxygen transmission rate of the package and its shelf life. If the barrier properties of the packaging material are not good, the oxygen entering the package during the shelf life is sufficient to cause the microorganisms to grow in a large amount, so that the possibility of deterioration of the food is greatly improved, but if the barrier property of the packaging material is too good, the packaging cost will be significantly increased. Therefore, it is of great significance to establish the correlation between the barrier properties of packaging materials and the shelf life of foods.
Languang Lab has carried out testing and research on this subject, and has purchased a large number of food samples in the shelf life and packaged from the market for the oxygen transmission rate of the package to comprehensively analyze the oxygen transmission rate of the package and its labeling period. Association. At present, the samples we tested were plastic bottles of different capacities containing carbonated drinks, milk drinks, and edible oils.
Among them, the test data of carbonated beverage plastic bottles have been obtained as follows:
Unit: ml/pkg•day.
The above data are the average of the test data of the three samples, and the test data will be continuously enriched. These data help us to find some rules. For example, after converting the test data into the amount of oxygen that can be contacted by a 1ml beverage, the smaller the volume of the beverage bottle, the greater the amount of oxygen that 1ml of the beverage is exposed to. Of course, when selecting packaging materials and designing the packaging structure, it is also necessary to take into account the consumption speed of the food, and the oxygen sensitivity of the special components in the formulation is also worthy of attention.
At present, the test data of milk beverages and edible oil packaging are still relatively small, but milk beverages generally choose PP or PE as packaging materials, so the overall oxygen transmission rate of the packaging is much larger than that of the same capacity carbonated beverage packaging.
3. Summary
Microbial growth is the most important cause of food spoilage, and the presence of oxygen is an important factor in microbial reproduction. Therefore, the oxygen barrier property of food packaging is very important. We believe that there is a close relationship between the overall oxygen transmission rate of the package and its shelf life. For this reason, Languang Lab is conducting extensive testing to obtain sufficient data for analysis, and these data will become the standard for food packaging. An important basis for the revision and reasonable selection of packaging forms and packaging materials.
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