The Analysis and Test of Correlation between Food Package and Its Shelf Life
Abstract
The main function of food package is to guarantee the food quality within its shelf life. But there is no specific standards which stipulate what kind of materials shall be used for food package or specify what kind of criteria should be reached by the food package. This article is to discuss the correlation between the food package and its shelf life through the factors that influencing food safety.
Food safety has become the public focus with the emerging incidents such as re-packed milk, food deterioration within shelf life and random production date mark for food in bulk. Public has been concerned about the shelf life of food recently. As an important protective cover, the flexible package plays a great role in guarantee the shelf life of food. This article is to discuss the correlation between the food package and its shelf life through the factors that influencing food safety.
1. Shelf Life of Food
At present, the shelf life of food is mainly decided by the food manufacturers themselves as there is no compulsory regulation made by the government. Limited by the testing technology and testing instruments, some manufacturers even decide the shelf life according to the experience or by rough estimation. Actually, how to define the shelf life of food is a common technical difficulty for most of the food manufacturers.Â
Physical & chemical indexes, hygiene indexes and sensory indexes are the three main aspects to evaluate whether the food is deteriorated. Physical & chemical indexes specify the ingredients and their content. Hygiene indexes are used to evaluate the contamination degree of the food by microbe or other sources. Sensory indexes are used to judge the flavor of the food. Different kinds of food are evaluated by different standards. For example, nutrient is evaluated by its composition while specialty is evaluated by its flavor. If the hygiene indexes are unqualified, it may lead to food safety problems.
Now, there are mainly 3 subjects concerning the shelf life of food. First, how to define the shelf life of food is a common problem for food manufacturers. The cost of accelerating test is too high for small and medium manufacturers to afford. Furthermore, there is no uniform testing method that could be adopted. Second, the food should not become deteriorated within shelf life. But in daily life, people care more about the date before which the food tastes good rather than whether the food is deteriorated. Third, new materials come into being for the application of food package. For example, if the food is packed in PE package, the shelf life may be only one month. However, the shelf life of the same food would be extended to as long as one year if it is packed in aluminum plastic package.
2. The Correlation between Flexible Package and Shelf Life
2.1 The Main Causes for Food Deterioration
For most of the food, the deterioration is mainly caused by reproduction of the microbe. In process of manufacturing, the quantity of microbe is minimized by washing, sterilization, baking and frying etc. But the microbe residual rate can be affected by the factors such as raw material physical and chemical condition, manufacturing craft and the microbial contamination degree. Besides, during the processing, transportation and storage, the finished food may be re contaminated by the microbe. The microbe residual in the finished food and the newly contaminated microbe will be reproduce under proper conditions and result in food deterioration.
Temperature, gas and humidity, etc. are closely related to the growth and reproduction of the microbe contained in the food. In actual storage, temperature and humidity could be controlled at a low cost. However, the content of the gas in the environment is quite difficult to control. Adequate oxygen in the environment would encourage the growth of aerobes. Since the growth rate of aerobes and the corresponding food deterioration rate are much faster than those of anaerobes, oxygen is regarded as one of the important factors that cause food deterioration.
2.2 The Analysis on Causes of Food Deterioration within Shelf Life
Food deterioration within shelf life would cause very serious consequences. However most of the food manufacturers regard the leakage occurred in process of transportation and improper operation as the main cause for food deterioration. More scientific test of the food package is in great demand which would help the food manufacture to figure out the real cause for food deterioration within shelf life. If there is no leakage in food package and the food is up to standards, then the design of package or the material of the package may be the cause for the deterioration problems. Â
2.3 The Correlation between the Barrier Property of Food Packaging Material and Shelf Life
Associated with the analysis mentioned above, it is easy to understand that the oxygen transmission rate of the whole package is closely related to its shelf life. The microbe may grow quickly in the package with low barrier property and the food inside the package is possibly going to be deteriorated. However the production cost would be increased by using high barrier packaging materials. Therefore it is of great importance to study the correlation between the barrier property of package and the shelf life of food which could help the food manufacturers to select proper packaging materials.Â
Labthink Lab has completed a research project on this subject.
Specimen: Plastic bottles of carbonated drinks, milk beverage and edible oil with various volumes.
Each value of the above data is the average value of 3 specimens. The data sheet will be further completed which could help us figure out the correlation. For example, convert the test data into the volume of oxygen for 1ml of the beverage, then it could be obtained that the smaller the bottle volume is, the more oxygen it would contact. Of course, the consumption rate should be taken into consideration when selecting packaging material and designing packages. Furthermore, the oxygen sensibility to certain composition contained in the product should also be considered.
3. Conclusion
The growth and reproduction of microbe is the main cause of food deterioration and the existence of oxygen is a most important factor for the reproduction of the microbe. Therefore, the oxygen barrier property of food package is critical to guarantee the shelf life of food. Based on experience of numerous tests, the following conclusion is reached by Labthink Lab that the oxygen transmission rate of the whole package is closely related to the shelf life of the food. A great number of tests are being performed in Labthink lab and we are trying to provide our customers with more and more actual test data for reference so that the food manufacturers could select the most suitable packaging materials in food production.
Detailed information,pls contact Emily Wu at sales@labthinkinternational.com or visit our website: www.labthinkinternational.com/ .
