The freshness of the hottest food is clear at a gl

2022-08-13
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Food preservation is clear at a glance

calibrate temperature measuring instruments. Are more than 47000 pieces of food packaged just for our convenience? The latest answer is "no". "Smart" packaging can more effectively protect the quality of food, or directly show whether the food is fresh, so that consumers do not have to wait until after unpacking to find out whether the food has gone bad

at present, the main basis for determining whether packaged food is deteriorated is the shelf life marked on the outer package. People usually think that food is safe and fresh as long as it is within the shelf life, but this is often not the case

first of all, the shelf life of food is related to environmental factors. Different temperatures, humidity, air circulation, etc. have a great impact on the shelf life of food and will not produce complications like other materials. Secondly, the quality of packaging materials and packaging technology will also affect the shelf life. Third, the shelf life is not the fresh-keeping period of food. The food within the shelf life can only ensure that the food has not deteriorated, but can not guarantee that the food has the original freshness and flavor

in the United States, France and other places, a variety of intelligent packaging technologies are being used in food packaging. They can not only indicate whether food is spoiled, but also extend the food preservation period, so as to effectively ensure the safety and original flavor of food

some fresh-keeping foods need to be preserved at low temperature, otherwise the bacteria in them will multiply and cause food deterioration. A new label that can indicate time and temperature is being used to show how long food has been stored at a certain temperature. This label is like a target for shooting. There are many transparent rings with ferrules. The central ring contains a chemical substance, which will polymerize with time and temperature, and change from transparent to black. If the packaged food is kept at a low temperature, the polymerization reaction 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 food will increase with the increase of temperature and time, the degree of Chemical Blackening will become more and more serious. When the inner circle turns black, it means that the food is no longer fresh. Consumers can judge whether the food is still edible through the change of label color

another Jinan experimental machine factory, Jinan new era gold testing instrument, and these two types of sensors are imitation of small signal output type Co., Ltd., a well-known food safety indication packaging technology in the country. It acts with the gas released by the food in the packaging bag to show whether the meat and vegetables are spoiled

for another example, in order to delay the deterioration of food due to oxidation, the current common practice is to put an iron powder packet in the package, and use the oxidation process of iron to consume the oxygen in the package. The new packaging is to add a layer of "oxygen absorbing" material to the packaging paper

at present, an American company is developing fresh-keeping instruction packaging for frozen food. This kind of package can detect the gas released after meat, fish and vegetables deteriorate due to improper storage. Different fruits and vegetables require different concentrations of oxygen and carbon dioxide for preservation, and packaging technology for this feature is also being developed

a company in California is developing a packaging film, which can change its permeability with temperature to meet the different needs of different fruits and vegetables for oxygen and carbon dioxide

in New Zealand, researchers are developing a kind of fruit packaging, which can indicate when fruits like peaches that are afraid of squeezing and pressing are ripe

reprinted from: Zhongqing

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