1, containing preservatives. In order to prolong the shelf life, preservatives (such as benzoic acid) should be added to canned food during production. Generally speaking, the preservatives added in canned food have no toxic effect on human body, and a small amount of them are relatively safe for short-term consumption, but they are harmful to liver and kidney if they are eaten frequently.
2, containing additives. Additives are added to canned food to make it delicious. Additives added in the processing of canned food include spices, pigments and artificial flavoring agents, which are harmful to children.
3. Vitamin loss. After canned food processing, about 10%-60% of vitamin C, 20%-80% of vitamin B 1, less than 10% of vitamin B2 and vitamin PP, 20%-30% of pantothenic acid and15%-
Preservatives (often used as benzoic acid) are added to canned fish, meat, fruits and vegetables. In order to extend the shelf life. Generally speaking, it is relatively safe to eat a small amount of canned food for a short time, but it is harmful to liver and kidney if you eat it regularly.
Matters needing attention in eating canned food
1. Check whether the canned food is out of date, rusted, especially swollen. If the lid of the can bulges, it means that the anaerobic bacteria in the can proliferate and produce acid and gas, and the food in the can has gone bad and can't be eaten any more.
If the canned food does not change color or taste after opening, only a layer of paper or leaves is seen, which is a technical measure taken by the manufacturer to keep fresh and enhance taste. For example, some canned fish, shrimp and ham are often lined with a layer of sulfuric acid paper, which is used to prevent some chemicals produced by the decomposition of fish and shrimp from contacting with tin cans and polluting spoiled food. It is harmless to human body, as long as it is removed.
2. It is being processed. Before eating canned food, if conditions permit, it is best to pack and cook it, which can not only sterilize but also improve the taste of food. Or return to the pot properly after boiling, and add some seasonings you like to arouse your appetite.
3.eat it in time. Canned food is nutritious and perishable. So after opening the can, it's best to eat it all at once. If you can't eat it all at once, it should not be left for a long time to avoid microbial invasion and pollution. Canned fruit is easily polluted by lactic acid bacteria and alcohol bacteria, resulting in bad taste and alcohol ignorance. Don't eat spoiled leftover cans.