Whether food is spoiled and packaged at any time

It is generally believed that packaged foods should be safe as long as they are within the shelf life, but in reality it is not always the case. In order to ensure food safety, some new packaging technologies that can indicate whether foods are deteriorating, and packaging techniques that can extend the shelf life of foods have emerged.

Food packaging researchers have found that some materials can absorb the oxygen in the bag, and some materials can interact with the gases produced when the food is spoiled, change color, and some materials change color when the temperature changes. If such materials are used to package foods, it will help prevent food from oxidizing and deteriorating, or provide consumers with more information on the safety of foods.

In order to delay the deterioration of food due to oxidation, the commonly used method is to put an iron powder packet inside the packaging bag and use the oxidation process of iron to consume the oxygen in the packaging bag. However, it is often uncomfortable to see small packets printed with the word “Don’t Eat” in food packaging bags.

A new type of packaging that adds a layer of “oxygen” material to the wrapper avoids the use of iron powder packets. For another example, some preserved foods need to be kept at a low temperature, otherwise the bacteria inside will multiply and cause food spoilage. A new type of label, which can indicate time and temperature, is attached to the package and shows how long the food has been stored at a certain temperature. This kind of label is like a target for shooting. There are many rings of transparent rings. The central ring contains a chemical substance that changes with time and temperature and causes polymerization to change from transparent to black. If the packaged food is kept at a low temperature, the polymerization of the chemical is very slow. Once the temperature increases, the polymerization reaction will accelerate and the chemical will change from transparent to black. As the bacteria in foods increase with temperature and time, the degree of darkening of chemical substances will become more and more serious. When the inner ring turns black, it means that the food is no longer fresh. Consumers can use this change in the color of the label to determine if the food has been stored at high temperatures for a long time. The use of such a label facilitates targeted selection of packaged foods by consumers and it is not easy to mistakenly select spoiled foods to avoid disputes with merchants due to food spoilage requirements.

There is also a food safety indicator packaging technology, which is a kind of dye-doped plastic disc that shows whether meat and vegetables are deteriorating by interacting with the gas released from the food in the packaging bag. Consumers can know if the food is deteriorating based on the color of the plastic sheet. This advanced packaging technology has been put into use in the United States, France and other places. Although the use of new technologies requires more investment, the potential commercial benefits are even greater. A frozen food fresh-keeping indicator package developed by the United States can monitor the gas released from meat, fish, and vegetables that have been rotted and deteriorated due to improper preservation.

There is also a kind of packaging film that can change the permeability with the change of temperature and meet the different needs of different fruits and vegetables for oxygen and carbon dioxide. A fruit package in New Zealand can indicate when the fruit in the package is ripe.

Reprinted from: China Packaging News