The naked eye cannot distinguish between fruits with chemicals

When storing preservatives, shiny fruits are as good as when being well fertilized and harvested in time. The medicinal fruits have a superficial appearance, so it is extremely difficult to distinguish between fruits and vegetables, experts say.

>>>Technology for pumping crab bricks, painting for guava

Recently, after the story of an apple bought by a woman in Hanoi until now, it is still fresh, many people are confused about fruits containing preservatives - a concern for many years. Many housewives leaked the secret to choosing safe, natural fruits. But according to experts studying food, food technology, it is difficult to distinguish fruits containing preservatives and ripening.

Ms. Nguyen Ngoc Anh Thu, director of a family training center in Bien Hoa, Dong Nai, said that although she loves to eat green apples, over a year ago, she did not dare to buy this fruit, after seeing her apple. Buy from the market, leave 4 months without broken."Can not rely on the appearance to choose safe fruits" , the culinary expert has spent a lot of time researching on food hygiene and safety issues and has a lot of experience in choosing kitchen materials. , affirmed.

Ms. Thu said that the chemicals used to preserve or promote them often do not leave any strange color, smell, taste, and create an eye-catching appearance for the product."The aim of the seller is to sell a lot of products, so they have to make the fruit look as natural as possible. I am really helpless when it comes to determining which fruit is safe. No, unless you know exactly where the fruit is, grown by anyone , " Ms Thu shared.

She said, to know exactly, only thanks to the technology of chemical analysis or fruit in the normal environment, over a long time. Relying on brands or buying in supermarkets is also difficult to put full trust after some cases of uncovering these units are also tricky."Maybe choose fruits that know for sure that it is Vietnamese and cheap (so they don't have an incentive to" craft ") like toads and grapefruit," Ms Thu said.

Apple fruit bought by Nguyen Ngoc Anh Thu for several months is still fresh.(Photo: Anh Thu)

Professor Nguyen Quang Thach, Institute of Agricultural Biology, University of Agriculture (Hanoi) said that at present, the use of chemicals to preserve and ripen fruits is very popular. There are many types of preservatives and in general, abuse is certainly not good for human health.The most dangerous chemical group is Auxin , of which 2,4-D is a substance - ingredient in herbicides, mixed at a rate of 5-10 parts per million for soaking and spraying to help fruit and vegetables freshen longer. Consumers who consume these fruits and vegetables, accumulate toxins after time may have cancer. Therefore, the auxin group has been banned for fruit preservation. However, at present, the use of food preservatives, including vegetables, is very blameless.

In addition to using chemicals to preserve fresh fruit for a long time, it is also urgently overcooked with Ethylene . This is a natural growth hormone in plants, plays a major role in stimulating ripening, aging and fruit loss. Taking advantage of this property, artificial ethylene is produced to make fruits ripen, or apply to mangoes, bananas, jackfruit . These chemicals are less toxic than preservatives if used. Use in normal and proper concentrations, of licensed establishments.

Last year, Dr. Pham Kim Phuong and students of Food Technology University, Saigon Technology University had a survey of food safety situation in some districts in Ho Chi Minh City and recorded the status of many traders. use chemicals to inject into jackfruit, plum to quickly ripen in just one day. This chemical has many trade names: Etherel (USA), Flodimex (Germany), Ethephon (Russia), must be mixed with water to be used. Each bag of chemicals costs 100,000 VND, injecting a few tons of jackfruit.

Survey and analysis showed that jackfruit was injected with chemicals, it was still fresh and sweet, but the outer part was awkward. Fruits that were injected with too much medicine should be ripe, if not empty. In addition, natural jackfruit fruit is very soft, jackfruit eyes bloom, spines are not sharp and sparse than when they are green, fruit is too ripe and cracked, smells very fragrant.

Chemical ripening ripening (on the left) and images of injecting ripe jackfruit in Ho Chi Minh City.(Photo: Excerpt from the survey report of Dr. Nguyen Kim Phuong and the student group)

However, in general, it must be very experienced and well-researched to be able to recognize these differences. For most fruits, it is difficult to distinguish whether or not to use preservatives and maturing agents. For example, according to Professor Pham Quang Thach, if using Auxin to preserve at high concentrations, the fruit will be green, or unusually large, when supplemented with a lot of porous foamy dry substances . However, if Preserving with this substance with a lower concentration, only make the fruit have a greener code than the fresh longer effect, while good fertilization can also help vegetables and fruits have a beautiful green color, eye-catching. the same, similar.

"In the current situation, we really cannot recommend consumers to choose this fruit or the other, based on certain characteristics, because there are no typical signs to identify them soaked. We can only recommend that they be more cautious when buying unidentified fruits, the most important thing is that authorities must strengthen the management of the use of chemicals. preserving and promoting vegetable and fruit growth as well as the circulation of these essential goods " , Prof. Thach expressed.

With this view, Master Bui Thi Minh Thuy, lecturer in the Faculty of Chemical and Food Technology, Nguyen Tat Thanh University, Ho Chi Minh City, also shared that it is difficult to distinguish the impregnated fruit from the outside. whether or not it can only accurately identify this when it is left for a long time at ambient temperature or replenished inside. For example, naturally, the fruit will be broken from the outside first and then inside but the fruits with many preservatives often outside are still shiny, fresh but clear and dark.

"Clearly harmful preservatives, at low concentrations, it has the effect of destroying microorganisms, but at high concentrations, or by nature of accumulation, it can 'destroy' all humans, because so this issue cannot be taken lightly, " said Thuy.