Holiday period, generally a lot of food at home will be saved. Now supermarket food packaging, food can only be easy to play instructions and the role of the prevention of food contamination. People usually think, as long as the packaging of food in the shelf-life period, it should be safe, but sometimes not the case. In order to ensure food safety, so that consumers do not eat spoiled food, the scientists can come up with some metamorphic instructions Whether or not a new type of food packaging technology and extend the shelf life of food packaging technologies, which collectively, the "active packaging technology," or "smart packaging technology" . Unfortunately, our country is currently far behind in this regard.
■ "smart" food from the "active" packaging

Food for the delay due to oxidation and deterioration, the current common practice is in the packaging into a powder inside the packet, the use of iron oxidation process spent inside the packaging of oxygen. However, some customers in the food to see which one printed "勿食" the words do not have to kick on the packet, and the new packaging is coupled with a layer of wrapping paper in "sucked" Materials oxygen, which can make them feel comfortable a lot of . Another instance, a number of fresh food at low temperatures necessary to preserve, or else the bacteria will be active inside, and cause food deterioration. Affixed to the packaging instructions on time and temperature of the new tags, one of the chemical composition at higher temperatures when the polymerization occurs, the corresponding tag will be light and shade of the color change, thus customers can know at what temperature food storage, storage How long, how in the end the degree of freshness.

According to the United Kingdom, "New Scientist" reports, such as "active packaging" technology, already in the United States, France and other places use. Many companies recognize that customers understand that the provision of fresh food to their correct, and its potential commercial benefits are enormous, the use of new technologies to develop additional cost compared with, but are "pale into insignificance." At present, some companies are developing the United States frozen food preservation instructions packaging, new packaging can be monitored to meat, fish or vegetables due to improper refrigeration decomposed metamorphic released gases. Different fresh fruits and vegetables needed for the concentration of oxygen and carbon dioxide are different characteristics for this packaging technology is also developing into. California company is developing a packaging film, this film can change its permeability with temperature capabilities, meet the needs of different fruits and vegetables of different oxygen and carbon dioxide necessary. In New Zealand, researchers at the development of a fruit packaging, this packaging instructions such as peach afraid afraid of pressure squeezing the fruit when cooked. Food Technology researchers estimated that in the coming 20-40 percent of the food packaging will be the application of "active packaging" technologies.

■ Whether or not food metamorphic instructions

The researchers found that food packaging, some materials can absorb oxygen bag packaging; Some Materials with the Food and metamorphic gases produced by the interaction time, change color; some material change in temperature will change color and so on. If the use of such materials packaged food, it helps prevent oxidative deterioration of food, or provide consumers with more food safe Whether or not information.

As a result of these active materials have a display of food packaging safety feature, so much the company is to research various forms of "active packaging." France's "Fujio price" supermarket chain is much fresh food on the use of a known as the "time temperature instructions" of the packaging technology. In fact it is a tag, you can show the food at a temperature kept many Long time. Labels such as used in target shooting, there is much transparent trap circle circle, the center of the ring contains a chemical substance. Such chemical substances over time and temperature difference in the polymerization by the transparent black. If the packaging of food at low temperature to maintain status, the chemical polymerization reaction is very slow, once the temperature increase in polymerization will be accelerated by chemical substances will be transparent black. Up because of food bacteria with temperature and time increased, so the extent of chemical substances will darken more and more serious. When the inner dark, it means that the food is no longer fresh. Consumers can change the color of this tag to determine whether the foods at high temperature state of preservation for a long time.

Researchers another food safety instructions packaging technology, is a dye-doped plastic wafer, through the food bags and packaging which play a role in the release of the gas, indicating whether the deterioration of meat and vegetables. Add this plastic film food packaging bags, if perishable food packaging bag, it will release a gas, so that plastic film to change color. Consumers under the color of plastic films will be able to know whether the foods metamorphism.

■ extend the shelf life

Different fruits and vegetables required at a certain concentration of oxygen and carbon dioxide can be fresh, and so the oxygen and carbon dioxide concentration in the sealed packaging bag is difficult to control. Because when the temperature is high, the packaging bag of fruit or vegetable will consume more oxygen and release more carbon dioxide. Therefore, if not regulated, the shelf life of food is bound to be affected.

In order to solve this dilemma, the United States Menlo Park, Calif., company is studying a so-called membrane Intelimer packaging. This film at the temperature changes, will change their permeability, so that different foods to keep in the best proportion of oxygen and carbon dioxide concentrations under.

Slow down the rate of food deterioration Another method is to use an oxygen scavenger to remove oxygen, control of the packaging bag of the air environment, thereby avoiding deterioration of food oxidation. The current commonly used method is put in the food packaging bag with a sachet of powder, through the iron consumed oxygen packaging bag. However, this method is obviously insufficient, because pouch on the "no eating" signs to warn consumers easily lead to resentment. To this end, the United States, New Jersey, a sealed gas company is the production itself can be an oxygen bag to remove the material. Materials such as iron, as capture and consumption of oxygen packaging bags.