Can irradiated food still be eaten?

When it comes to irradiated food, many consumers may not know much about it. In fact, it can be seen everywhere in our lives, and many people often eat irradiated food. For example, instant noodles, the seasoning package inside is irradiated, and on the outer packaging of instant noodles, it says: "dehydrated vegetables and spices are treated by internationally accepted irradiation sterilization technology." There are also chicken feet with pickled peppers, and the outer packaging directly says irradiated food. In addition to these foods, many foods are often irradiated, such as garlic, potatoes, livestock and poultry meat, frozen aquatic products and so on.

Why should food be irradiated?

As we all know, the shelf life of fresh meat is very short. If left at room temperature, it will deteriorate in less than two days. The spoilage of fresh meat is caused by microorganisms, and meat is a very good food for microorganisms. On the surface of fresh meat, some microorganisms have settled on it, but the number is very small and will not pose a threat to human health. However, if it is left at room temperature and no measures are taken, with the passage of time, microorganisms will multiply and produce toxic metabolites. People will cause acute poisoning, nausea, vomiting, diarrhea, abdominal pain, dizziness and other symptoms, and even coma or even death due to heart failure.

We certainly don't want this to happen, so how can we preserve meat? What magic weapon do we have in this war against microorganisms? First of all, the most commonly used is low temperature. Inhibiting the growth of microorganisms at low temperature is an effective way to extend the shelf life. For example, it can be stored for more than a week under the condition of 4 degrees refrigeration. There are also heating, smoking and curing, which are effective methods to inhibit the growth of microorganisms in meat products and extend the shelf life, but these methods change the nature and quality of meat and limit the use of meat. There is another way that consumers are most unwilling to accept, that is, adding preservatives to inhibit the growth and reproduction of microorganisms through the role of preservatives, but adding too much preservatives is also harmful to human health.

Is there any way to extend the shelf life without affecting the quality of meat? The answer is irradiation technology.

Let's prove it through experiments. We divide the fresh meat bought in the supermarket into two parts, one untreated and the other irradiated. The radiation dose was 1 kg force (1 gray = 1 kg). In order to reflect the repeatability of the experiment, we divided each large portion of meat into three small portions, packed them in self-sealing bags and labeled them. We put three raw meats in a constant temperature incubator at 20℃, and the other three meats were sent to the cobalt source room of a research institution in Beijing for irradiation. After about 20 minutes, the meat will be irradiated. We also put the irradiated meat in a constant temperature incubator. Four days later, we took the meat out for observation. We can see directly and clearly with naked eyes that irradiated meat is still in a relatively bright red state, while the surface of non-irradiated meat is white and red, with obvious smell and deterioration. We continued to observe after another day, and the deterioration degree of non-irradiated meat was more obvious, while irradiated meat remained fresh.

Irradiation technology actually uses ionizing radiation energy generated by radionuclides or high-energy electron beams to kill harmful microorganisms in food. On the one hand, it can improve the hygiene and safety of food and reduce food-borne diseases; On the other hand, it can also reduce the use of preservatives.

Another application of irradiation technology in food is to inhibit germination.

As we know, potatoes germinate easily in a humid environment. After potatoes germinate, they will produce a toxin called Solanum nigrum, which is very irritating and corrosive to gastrointestinal mucosa and has a paralyzing effect on the central nervous system. The main symptoms of poisoning are aggravated stomachache, nausea, vomiting, dyspnea and shortness of breath, accompanied by general weakness and failure, which can lead to death in severe cases. Let's confirm the effect of irradiation on potato germination through experiments. We bought six potatoes from the supermarket, put them in self-sealed bags and labeled them. Three potatoes were untreated and three potatoes were irradiated. The radiation dose was 0.5 kg-force. We put three untreated potatoes in a constant temperature incubator at 20℃, while the other three were sent to be irradiated. We also put the irradiated potatoes in a constant temperature incubator. After standing for 7 days, we took out the potatoes for observation. We can see that the irradiated potato surface has not changed at all, while the unirradiated potato has begun to sprout. After three days, irradiated potatoes did not change, but non-irradiated potatoes germinated obviously.

Does irradiation affect food?

The detection of nutritional components of irradiated food shows that the irradiation treatment with a specified dose will not lead to obvious loss of nutritional quality of food, and protein, sugar and fat in food will remain relatively stable, while essential amino acids, fatty acids, minerals and trace elements will not lose too much. The World Health Organization, the Food and Agriculture Organization of the United Nations and the International Atomic Energy Agency issued a joint report in the 1980s. Like other food processing technologies, irradiation technology is safe, and its damage to food nutrients does not exceed that of traditional processing methods. Irradiation technology is a safe and reliable food processing technology, and there is no safety problem in the food irradiated according to the prescribed dose.

The radiation used to irradiate food is released by radioactive sources, so is irradiated food radioactive?

Consumers don't have to worry about this. First of all, when food is irradiated, it will not directly contact the radioactive source, but only get the energy released by radiation; Secondly, the energy used to irradiate food is relatively low, which is lower than the critical energy required for the excitation of elements in food, so the substances in food will not be excited to produce induced radioactivity during irradiation. The radioactive food that consumers are worried about is the food contaminated by radioactive particles. For example, the leakage of nuclear power plants causes radioactive particles to adhere to the surface of food, thus causing radioactive pollution. Such food is called radioactive food. Therefore, irradiated food is essentially different from radioactive food.

According to national regulations, as long as food or food ingredients are irradiated, there must be irradiation marks or corresponding text marks. Since irradiated food is safe, why does the state stipulate that the packaging of irradiated food should be labeled? On the one hand, it protects consumers' right to know, and consumers have the right to choose whether to buy irradiated food; On the other hand, it is also to prevent food or ingredients from being repeatedly irradiated, because the Measures for the Hygienic Management of Irradiated Food stipulates that most foods are not allowed to be repeatedly irradiated.

As a mature and safe technology, irradiation technology has been commercialized in more than 50 countries around the world. China officially approved irradiated foods in the 1980s, and at present, it has approved six categories of foods, such as cereal bean products, dried fruits and preserved fruits, cooked livestock and poultry meat, frozen packaged livestock and poultry meat, condiments and fresh fruits and vegetables, to be irradiated. As long as the irradiation treatment process conforms to the national regulations, irradiated food not only has no impact on human health, but also improves the hygiene and safety, so consumers can safely eat it.