Recently, online media exposed that some merchants produce and operate "gold foil food".
According to the relevant laws and regulations of edible agricultural products in China and the national food safety standards, gold (silver) foil and gold (silver) powder substances (hereinafter referred to as gold and silver foil powder) are not food.
Raw materials or food additives cannot be used in the production and operation of edible agricultural products and processed food
.
In essence, the "net celebrity phenomenon" of consumers blindly pursuing gold and silver foil powder agricultural products is mainly due to the fact that consumers do not fully understand gold and silver foil powder
.
So, what is edible gold leaf powder? Is it harmful to health?
Improper use of gold and silver foil powder promotes extravagance
Gold has excellent ductility and ductility, second only to platinum, and is one of the most ductile metals
.
Therefore, gold is very easy to be made into thin sheets, which is commonly known as "gold foil".
One gram of gold can be made into gold foil with a thickness of 1/10,000 millimeter of 0.
5 square meters; at the same time, gold can also be made into powder by chemical or physical methods.
Also known as "gold powder" (not "gold powder" in metallurgical terminology, it is copper-zinc alloy), the ultra-fine powder of some processes can even reach nanometer size, and the surface area of a few grams of nanometer "gold powder" even exceeds the size of a football field
.
Therefore, when illegal traders use gold and silver foil powder as food additives, the dosage is not large and the cost is not high.
For example, the cost of gold foil in a certain brand of gold foil wine is only a few yuan (less than 0.
02 grams per kilogram), but The selling price has soared exponentially, which can be described as "a huge profit", which has greatly contributed to the trend of extravagance, and also stimulated the bad trend that profit-seeking companies are exaggerated and profit-seeking
.
The health and safety hazards of gold and silver foil powder cannot be ignored
It is not necessary to add gold and silver foil powder to food or edible agricultural products
.
On the one hand, gold has excellent corrosion resistance, but it does not mean that it cannot be absorbed by the human body
.
Gold is only soluble in strong corrosive substances such as aqua regia, but not in common acid and alkali, so gold cannot be digested by gastric acid (hydrochloric acid), and larger-sized gold foil cannot be absorbed by the intestinal tract
.
Therefore, some gold and silver foil powder users blindly promote their "absolute safety"
.
However, some ultra-fine gold and silver powders can be absorbed by the human body, and nano-sized gold and silver particles can even penetrate the cell wall and directly enter the cell interior, resulting in oxidative stress.
The cytotoxicity and physiological toxicity of gold and silver nanoparticles have been partially confirmed, and their potential health and safety risks need to be vigilant
.
On the other hand, gold itself is not an essential element for the human body, and there is absolutely no need to eat it
.
The so-called medical effects of gold in some ancient medical books mentioned on the Internet are also controversial, and they are mostly used as advertising gimmicks; a small amount of gold and silver foil powder will neither enhance the taste and aroma of agricultural products, nor have any nutritional value, nor can it achieve "Antibacterial" or extending the shelf life of produce
.
The risk of heavy metal impurities in gold and silver foil powder is always present
What's more, 100% "pure gold" does not exist in the real world
.
Some manufacturers are hotly promoting the so-called "pure gold" (24K gold), and its purity is only 99.
6%.
Heavy metals such as cadmium, chromium, nickel, lead, copper, antimony, and bismuth are often introduced into gold during the smelting process.
mg/kg to several thousand mg/kg, which is much higher than the content of heavy metal elements in ordinary edible agricultural products
.
These elements have different solubility in gastric acid, can be absorbed by the body and accumulate in organs and bones
.
Although the intake of gold and silver foil powder itself is not high, due to the accumulation and persistence of heavy metal elements, the health cumulative risk of long-term consumption needs to be paid attention to
.
What is even more vigilant is that even illegal traders use low-purity gold or copper-containing alloys to make gold foil powder, which aggravates the health risk of heavy metal intake and increases the difficulty of monitoring the quality and safety of agricultural products
.
Mao Xuefei, Liu Haihua
(Institute of Agricultural Quality Standards and Testing Technology, Chinese Academy of Agricultural Sciences)
