Clipping Board » Illness Enters through Mouth ─ The information that has been made public is often just the tip of the iceberg...
Author: Zhu Xueyuan, September 16, 2008
Perhaps everyone still remembers the incident in 2007 when a pet food company in Xuzhou, China, exported cat and dog food to the United States, adding melamine to the pet food to fake protein content, causing a huge uproar in Sino-American relations? Melamine is a very common plastic chemical raw material, and the biggest characteristic of its molecule is that it contains a lot of nitrogen atoms. This characteristic is nothing special in itself, as there are countless chemical raw materials with similar traits, but this alone does not make melamine so famous.
We know that the food industry often needs to check protein content, but directly measuring protein content is technically complex and costly, making it unsuitable for widespread promotion. Therefore, the industry often uses a method called the "Kjeldahl method" to indirectly estimate protein content based on the nitrogen content in food. That is, the higher the nitrogen content in food, the higher the protein content. Thus, the previously obscure melamine, due to its molecule containing a relatively high number of nitrogen atoms, became very useful.
Melamine is an organic nitrogen-containing heterocyclic compound, scientifically known as 1,3,5-triazine-2,4,6-triamine, or 2,4,6-triamino-1,3,5-triazine, abbreviated as triamine, melamine, or cyanuramide. It is an important chemical raw material, mainly used to condense with aldehydes to produce melamine-formaldehyde resin, which is used to make plastics. This type of plastic is not easily flammable, resistant to water, heat, aging, electric arcs, and chemical corrosion, with good insulation properties and mechanical strength. It is an indispensable raw material for wood, coatings, papermaking, textiles, leather, and electrical appliances. It can also be used to make glue and flame retardants, and in some Asian countries, it is used to manufacture fertilizers.
The biggest characteristic of melamine is its high nitrogen content (66%), coupled with its simple production process and low cost, providing a strong profit motive for adulterators and counterfeiters. It has been estimated that to increase the protein content by one percentage point in plant protein powder and feed, the cost of using melamine is only 1/5 of that of real protein raw materials. Therefore, the main reason for adding melamine is to "increase" the apparent protein content of products. As a white crystalline powder, melamine has no significant odor or taste, making it difficult to detect when adulterated, which also contributes to the opportunistic behavior of adulterators and counterfeiters.
The 1994 "International Chemical Safety Handbook" Volume III, co-edited by the International Programme on Chemical Safety and the European Union Commission, and the International Chemical Safety Cards only state that long-term or repeated high intake of melamine may affect the kidneys and bladder, leading to the formation of stones.
Melamine was first used by Chinese counterfeiters in livestock feed production. When added to feed, instruments detect a high number of nitrogen atoms, and by inference, a high protein content, allowing producers to save on expensive protein powder costs. Although melamine is toxic, cattle and sheep are large in size with strong kidney functions, able to metabolize the toxin smoothly, and there were no reports of cattle or sheep dying from it, so no one paid much attention. Naturally, counterfeiters expanded its application, also using melamine in pet food exported to the United States. Unfortunately, pets like cats and dogs are much smaller than cattle and sheep, with weaker metabolic abilities, making the toxic effects of melamine more pronounced, resulting in the poisoning of pets, which alarmed American authorities, and eventually brought melamine to the attention of the FDA.
It is said that when Americans discovered melamine, they were puzzled, not knowing why it was added, and initially thought it was due to contamination by rat poison.At the time, American news media reports were skeptical, suggesting that lax oversight in Chinese grain storage had led to contamination by rat poison. It wasn't until a knowledgeable Chinese individual couldn't hold back any longer and secretly informed Americans about the secret of adding melamine to food that the highly skilled American academic community finally realized the complex high-tech process of counterfeiting.
Everyone should pay attention to the Sanlu milk powder incident. The "contaminated" products were all the cheapest infant formula, priced at 18 yuan per bag. Clearly, Sanlu adopted a low-price dumping strategy to capture the rural milk powder market, the last piece of lucrative territory. However, selling milk powder at 18 yuan per bag doesn't even cover the cost, so mass production would surely lead to significant losses. To save costs, Sanlu added cheap soy protein powder to the milk powder as a substitute. While soy protein powder itself isn't a big issue, this time it was adulterated with melamine, a high-tech substance used to fake protein content, ultimately leading to the nationwide Sanlu milk powder scandal. Of course, adult milk powder must also have been adulterated with this high-tech substance, as adults have much stronger metabolic capabilities than infants, and except for special cases, naturally, no poisoning incidents would occur. Additionally, if you want to know how widespread the use of melamine is in China's food and feed industries, just Google "protein essence" and see the results for yourself. In fact, there are now even more advanced counterfeit products than melamine, capable of "resisting water washing tests" and "resisting ammonia nitrogen reactions." In short, even your high-tech grandpa couldn't detect that it's fake protein.
The Sanlu milk powder incident, from one perspective, reflects the severe food safety issues in China. What can we still safely eat? The black hand of melamine, starting from the initial cattle and sheep feed market, has spread to the infant formula sector today. I think hundreds of millions of Chinese people, unknowingly, have been eating pork, beef, and chicken fed with melamine for many years, and drinking adult milk powder adulterated with melamine for many years, all unknowingly contaminated by melamine. Has anyone conducted long-term tests on the health effects of melamine on humans? I'm sure no one has, because no one would have thought that hundreds of millions of people in a country would end up consuming a raw material from the plastics industry that has nothing to do with food.
Many people drink milk to supplement calcium, but if you pay attention to the labels on domestic fresh milk packaging, the calcium content is generally not listed. The nutritional components listed are usually only two: fat and protein. Fresh milk can be categorized as whole, low-fat, or skim, with varying fat content. In today's world where fat is often seen as a health hazard, most people don't care much about whether the fat content meets standards. Protein is the main nutritional component in milk, and fresh milk packaging typically states that the protein content is ≥2.9 grams per 100 milliliters, indicating compliance with the national standard for fresh milk (≥2.95 grams per 100 milliliters).
The protein content of raw fresh milk is generally above 3%, so it usually meets the national standard unless water is added to the raw milk. To prevent people from selling water at the price of milk, it is necessary to test the protein content when purchasing raw fresh milk. Based on the chemical properties of protein, there are several testing methods, each with its own advantages and disadvantages. The Kjeldahl method, widely adopted in the food industry and established as a national standard, is a method invented by Danish chemist Johan Kjeldahl in the late 19th century. The principle is simple: protein contains nitrogen, and by treating the sample with strong acid to release the nitrogen from the protein, the nitrogen content can be measured to calculate the protein content. The nitrogen content of milk protein is about 16%, and according to the national standard, the measured nitrogen content is multiplied by 6.38 to determine the protein content.
Therefore, the Kjeldahl method does not actually measure protein content directly but estimates it by measuring nitrogen content. Obviously, if the sample contains other nitrogen-containing compounds, this method becomes inaccurate. Under normal circumstances, this is not a problem because the main components in food that contain nitrogen are proteins, while other main components (carbohydrates, fats) do not contain nitrogen. Thus, the Kjeldahl method is a very accurate way to measure protein content. However, if someone adds other nitrogen-containing substances to the sample, they can deceive the Kjeldahl method into showing a falsely high protein content, allowing diluted milk to pass as raw milk.
A commonly used nitrogen-containing substance to fake protein is urea. However, urea's nitrogen content is not very high (46.6%), and when dissolved in water, it emits a pungent ammonia smell, making it easy to detect. Additionally, a simple testing method (the Griess reagent method) can determine whether urea has been added to milk. As a result, counterfeiters later switched to using melamine. Melamine has a high nitrogen content of 66.6% (the higher the nitrogen content, the more protein it can fake), is white and odorless, and lacks a simple detection method (requiring high-tech methods like "high-performance liquid chromatography" for detection), making it an ideal protein substitute. Melamine is an important industrial chemical widely used in the production of synthetic resins, plastics, coatings, etc., with a current price of about 12,000 yuan per ton. During the production of melamine, waste residue is generated, which still contains 70% melamine. Counterfeiters use this melamine residue to fake protein, and many "biotech companies" in China promote "protein essence" online, which is essentially melamine residue. Adding "protein essence" to feed and dairy products to fake protein has become an open secret, and its popularity has driven up the price of this otherwise free industrial waste to 300–400 yuan per ton.
How is melamine added to milk? There are two possible ways. One is adding it to raw milk at milk collection stations. This has certain limitations because melamine is slightly soluble in water, with a solubility of 3.1 grams per liter at room temperature.In other words, 100 milliliters of water can dissolve 0.31 grams of melamine, containing 0.2 grams of nitrogen, equivalent to 1.27 grams of protein. From this, it can be calculated that to meet the requirement of 100 milliliters containing at least 2.95 grams of protein, a maximum of 75 milliliters of water can be added to 100 milliliters of milk (along with 0.54 grams of melamine). Another method is to add melamine during the production of milk powder, which is not limited by solubility and allows for any amount to be added.
The reason melamine has been used as a "protein enhancer" domestically is likely due to the perception that it has very low toxicity and is not lethal. The oral lethal dose (LD50, a common toxicological indicator referring to the dose that causes death in half of the test subjects) of melamine in rats is about 3 grams per kilogram of body weight, similar to that of table salt. High-dose feeding of melamine to rats, rabbits, and dogs has not shown significant signs of poisoning. Melamine seems not to be metabolized in the body but is excreted unchanged in urine. However, animal experiments have also shown that long-term feeding of melamine can lead to kidney and bladder stones composed mainly of melamine and can induce bladder cancer. In 2007, pet food exported from China to the United States caused kidney failure and death in many pets, with investigations suggesting that melamine contamination in the pet food was the cause. So, does melamine have the same toxicity to humans? We cannot conduct experiments on humans, and even if people with kidney stones have consumed food adulterated with melamine, it is difficult to confirm melamine as the culprit unless the patient's food source is very limited, such as infants who only consume formula milk—unexpectedly, someone dared to use infants as test subjects to prove that it can be lethal!
Some argue that since the flaws in protein testing methods have led to fatal adulteration, it might as well be better to abolish protein testing altogether and tacitly allow the dilution of milk with water. In fact, the flaws in the Kjeldahl method are not difficult to remedy; it only requires an additional step: treating the sample with trichloroacetic acid first. Trichloroacetic acid can precipitate proteins, and after filtration, the nitrogen content in the precipitate and the filtrate can be measured separately to determine the true protein content and the nitrogen content masquerading as protein. This is a basic principle in biochemistry and has long been an international standard (ISO 8968) for testing nitrogen content in milk. The "protein enhancer" scam has been around domestically for some years, and the "Sanlu milk powder" incident merely brought this "industry secret" to public attention. Only by improving national standards and plugging loopholes can we restore public confidence in the domestic dairy industry.
Source: http://blog. sina. com. cn/ s/ blog_474068790100au5o. html
China Times / Huang Tianru, Zhang Cuifen / Taipei Report 2008/09/26
Melamine is an inedible chemical raw material, yet the government allows a certain amount in food. Isn't that going too far? Experts invited to the Department of Health press conference yesterday stated that, similar to dioxin or pesticide testing, while a detection value of zero is ideal, the reality is that even the most precise instruments have limits, and 2.5 ppm is already a very strict standard.
Dr. Yang Zhenchang, attending physician at the Clinical Toxicology Department of Taipei Veterans General Hospital, mentioned that considering the EU's standard for melamine release from food containers like melamine ware is 30 ppm, the Department of Health's food content detection standard of 2.5 ppm is indeed quite stringent.
He explained that if acute toxicity intensity is divided into extremely toxic, highly toxic, moderately toxic, and low toxicity, the allowable exposure level of melamine in rat experiments is 3161 mg per kilogram of body weight (at which point half of the test rats would die). For a 60 kg adult, this would mean consuming 189.7 grams at once to potentially be fatal, classifying it as a low-toxicity substance.
In terms of chronic toxicity, animal experiments also show that 90% of melamine is excreted from the body within a day of ingestion. In other words, melamine does not accumulate in the body and does not have genotoxic effects such as causing birth defects. The only concern is that continuous daily intake might lead to urinary tract stones.
Dr. Yang emphasized that according to the U.S. Food and Drug Administration's (FDA) daily allowable intake recommendation for melamine, it is 0.63 mg per kilogram of body weight. This figure is derived from rat animal experiments divided by 100 (as a tenfold safety factor is required for cross-species or individual differences).
Based on the above allowable intake and the detection standards announced by the Department of Health, a 60 kg adult could consume 15 kg of food containing 2.5 ppm melamine every day for 70 years without any issues.
Dr. Lin Bingxi, director of the Nephrology Department at Shin Kong Wu Ho-Su Memorial Hospital, stated that melamine has poor water solubility, which can lead to crystal formation during human metabolism, potentially causing stones. However, for nephrologists, as long as one drinks plenty of water or undergoes extracorporeal shock wave lithotripsy, stones are a completely curable condition.
Dr. Zheng Jihui and Dr. Yu Meijing from the Pediatric Nephrology Department, and Dr. Wang Damin and Dr. Chen Xiaowen from the Pediatric Urology Department at Linkou Chang Gung Children's Medical Center jointly stated yesterday that pharmacological and animal experimental evidence shows that melamine is almost entirely metabolized by the kidneys, with 90% excreted in urine within 24 hours of ingestion. This indicates that the kidneys clear melamine at a very fast rate. As long as it is not consumed in large amounts over a long period, there is no need for excessive concern. The best prevention is to develop habits of drinking plenty of water and urinating frequently.
Source: http:/ / times. hinet. net/ times……id=1758023& option=recreation
Why was Melamine Found in Sanlu Milk Powder?
Perhaps everyone still remembers the incident in 2007 when a pet food company in Xuzhou, China, exported cat and dog food to the United States, adding melamine to the pet food to fake protein content, causing a huge uproar in Sino-American relations? Melamine is a very common plastic chemical raw material, and the biggest characteristic of its molecule is that it contains a lot of nitrogen atoms. This characteristic is nothing special in itself, as there are countless chemical raw materials with similar traits, but this alone does not make melamine so famous.
We know that the food industry often needs to check protein content, but directly measuring protein content is technically complex and costly, making it unsuitable for widespread promotion. Therefore, the industry often uses a method called the "Kjeldahl method" to indirectly estimate protein content based on the nitrogen content in food. That is, the higher the nitrogen content in food, the higher the protein content. Thus, the previously obscure melamine, due to its molecule containing a relatively high number of nitrogen atoms, became very useful.
Melamine is an organic nitrogen-containing heterocyclic compound, scientifically known as 1,3,5-triazine-2,4,6-triamine, or 2,4,6-triamino-1,3,5-triazine, abbreviated as triamine, melamine, or cyanuramide. It is an important chemical raw material, mainly used to condense with aldehydes to produce melamine-formaldehyde resin, which is used to make plastics. This type of plastic is not easily flammable, resistant to water, heat, aging, electric arcs, and chemical corrosion, with good insulation properties and mechanical strength. It is an indispensable raw material for wood, coatings, papermaking, textiles, leather, and electrical appliances. It can also be used to make glue and flame retardants, and in some Asian countries, it is used to manufacture fertilizers.
The biggest characteristic of melamine is its high nitrogen content (66%), coupled with its simple production process and low cost, providing a strong profit motive for adulterators and counterfeiters. It has been estimated that to increase the protein content by one percentage point in plant protein powder and feed, the cost of using melamine is only 1/5 of that of real protein raw materials. Therefore, the main reason for adding melamine is to "increase" the apparent protein content of products. As a white crystalline powder, melamine has no significant odor or taste, making it difficult to detect when adulterated, which also contributes to the opportunistic behavior of adulterators and counterfeiters.
The 1994 "International Chemical Safety Handbook" Volume III, co-edited by the International Programme on Chemical Safety and the European Union Commission, and the International Chemical Safety Cards only state that long-term or repeated high intake of melamine may affect the kidneys and bladder, leading to the formation of stones.
Melamine was first used by Chinese counterfeiters in livestock feed production. When added to feed, instruments detect a high number of nitrogen atoms, and by inference, a high protein content, allowing producers to save on expensive protein powder costs. Although melamine is toxic, cattle and sheep are large in size with strong kidney functions, able to metabolize the toxin smoothly, and there were no reports of cattle or sheep dying from it, so no one paid much attention. Naturally, counterfeiters expanded its application, also using melamine in pet food exported to the United States. Unfortunately, pets like cats and dogs are much smaller than cattle and sheep, with weaker metabolic abilities, making the toxic effects of melamine more pronounced, resulting in the poisoning of pets, which alarmed American authorities, and eventually brought melamine to the attention of the FDA.
It is said that when Americans discovered melamine, they were puzzled, not knowing why it was added, and initially thought it was due to contamination by rat poison.At the time, American news media reports were skeptical, suggesting that lax oversight in Chinese grain storage had led to contamination by rat poison. It wasn't until a knowledgeable Chinese individual couldn't hold back any longer and secretly informed Americans about the secret of adding melamine to food that the highly skilled American academic community finally realized the complex high-tech process of counterfeiting.
Everyone should pay attention to the Sanlu milk powder incident. The "contaminated" products were all the cheapest infant formula, priced at 18 yuan per bag. Clearly, Sanlu adopted a low-price dumping strategy to capture the rural milk powder market, the last piece of lucrative territory. However, selling milk powder at 18 yuan per bag doesn't even cover the cost, so mass production would surely lead to significant losses. To save costs, Sanlu added cheap soy protein powder to the milk powder as a substitute. While soy protein powder itself isn't a big issue, this time it was adulterated with melamine, a high-tech substance used to fake protein content, ultimately leading to the nationwide Sanlu milk powder scandal. Of course, adult milk powder must also have been adulterated with this high-tech substance, as adults have much stronger metabolic capabilities than infants, and except for special cases, naturally, no poisoning incidents would occur. Additionally, if you want to know how widespread the use of melamine is in China's food and feed industries, just Google "protein essence" and see the results for yourself. In fact, there are now even more advanced counterfeit products than melamine, capable of "resisting water washing tests" and "resisting ammonia nitrogen reactions." In short, even your high-tech grandpa couldn't detect that it's fake protein.
The Sanlu milk powder incident, from one perspective, reflects the severe food safety issues in China. What can we still safely eat? The black hand of melamine, starting from the initial cattle and sheep feed market, has spread to the infant formula sector today. I think hundreds of millions of Chinese people, unknowingly, have been eating pork, beef, and chicken fed with melamine for many years, and drinking adult milk powder adulterated with melamine for many years, all unknowingly contaminated by melamine. Has anyone conducted long-term tests on the health effects of melamine on humans? I'm sure no one has, because no one would have thought that hundreds of millions of people in a country would end up consuming a raw material from the plastics industry that has nothing to do with food.
The "Protein Essence" Scam
The protein content of raw fresh milk is generally above 3%, so it usually meets the national standard unless water is added to the raw milk. To prevent people from selling water at the price of milk, it is necessary to test the protein content when purchasing raw fresh milk. Based on the chemical properties of protein, there are several testing methods, each with its own advantages and disadvantages. The Kjeldahl method, widely adopted in the food industry and established as a national standard, is a method invented by Danish chemist Johan Kjeldahl in the late 19th century. The principle is simple: protein contains nitrogen, and by treating the sample with strong acid to release the nitrogen from the protein, the nitrogen content can be measured to calculate the protein content. The nitrogen content of milk protein is about 16%, and according to the national standard, the measured nitrogen content is multiplied by 6.38 to determine the protein content.
Therefore, the Kjeldahl method does not actually measure protein content directly but estimates it by measuring nitrogen content. Obviously, if the sample contains other nitrogen-containing compounds, this method becomes inaccurate. Under normal circumstances, this is not a problem because the main components in food that contain nitrogen are proteins, while other main components (carbohydrates, fats) do not contain nitrogen. Thus, the Kjeldahl method is a very accurate way to measure protein content. However, if someone adds other nitrogen-containing substances to the sample, they can deceive the Kjeldahl method into showing a falsely high protein content, allowing diluted milk to pass as raw milk.
A commonly used nitrogen-containing substance to fake protein is urea. However, urea's nitrogen content is not very high (46.6%), and when dissolved in water, it emits a pungent ammonia smell, making it easy to detect. Additionally, a simple testing method (the Griess reagent method) can determine whether urea has been added to milk. As a result, counterfeiters later switched to using melamine. Melamine has a high nitrogen content of 66.6% (the higher the nitrogen content, the more protein it can fake), is white and odorless, and lacks a simple detection method (requiring high-tech methods like "high-performance liquid chromatography" for detection), making it an ideal protein substitute. Melamine is an important industrial chemical widely used in the production of synthetic resins, plastics, coatings, etc., with a current price of about 12,000 yuan per ton. During the production of melamine, waste residue is generated, which still contains 70% melamine. Counterfeiters use this melamine residue to fake protein, and many "biotech companies" in China promote "protein essence" online, which is essentially melamine residue. Adding "protein essence" to feed and dairy products to fake protein has become an open secret, and its popularity has driven up the price of this otherwise free industrial waste to 300–400 yuan per ton.
How is melamine added to milk? There are two possible ways. One is adding it to raw milk at milk collection stations. This has certain limitations because melamine is slightly soluble in water, with a solubility of 3.1 grams per liter at room temperature.In other words, 100 milliliters of water can dissolve 0.31 grams of melamine, containing 0.2 grams of nitrogen, equivalent to 1.27 grams of protein. From this, it can be calculated that to meet the requirement of 100 milliliters containing at least 2.95 grams of protein, a maximum of 75 milliliters of water can be added to 100 milliliters of milk (along with 0.54 grams of melamine). Another method is to add melamine during the production of milk powder, which is not limited by solubility and allows for any amount to be added.
The reason melamine has been used as a "protein enhancer" domestically is likely due to the perception that it has very low toxicity and is not lethal. The oral lethal dose (LD50, a common toxicological indicator referring to the dose that causes death in half of the test subjects) of melamine in rats is about 3 grams per kilogram of body weight, similar to that of table salt. High-dose feeding of melamine to rats, rabbits, and dogs has not shown significant signs of poisoning. Melamine seems not to be metabolized in the body but is excreted unchanged in urine. However, animal experiments have also shown that long-term feeding of melamine can lead to kidney and bladder stones composed mainly of melamine and can induce bladder cancer. In 2007, pet food exported from China to the United States caused kidney failure and death in many pets, with investigations suggesting that melamine contamination in the pet food was the cause. So, does melamine have the same toxicity to humans? We cannot conduct experiments on humans, and even if people with kidney stones have consumed food adulterated with melamine, it is difficult to confirm melamine as the culprit unless the patient's food source is very limited, such as infants who only consume formula milk—unexpectedly, someone dared to use infants as test subjects to prove that it can be lethal!
Some argue that since the flaws in protein testing methods have led to fatal adulteration, it might as well be better to abolish protein testing altogether and tacitly allow the dilution of milk with water. In fact, the flaws in the Kjeldahl method are not difficult to remedy; it only requires an additional step: treating the sample with trichloroacetic acid first. Trichloroacetic acid can precipitate proteins, and after filtration, the nitrogen content in the precipitate and the filtrate can be measured separately to determine the true protein content and the nitrogen content masquerading as protein. This is a basic principle in biochemistry and has long been an international standard (ISO 8968) for testing nitrogen content in milk. The "protein enhancer" scam has been around domestically for some years, and the "Sanlu milk powder" incident merely brought this "industry secret" to public attention. Only by improving national standards and plugging loopholes can we restore public confidence in the domestic dairy industry.
Source: http://blog. sina. com. cn/ s/ blog_474068790100au5o. html
Drink More Water to Detox: Seven Doctors Say No Worries
Melamine is an inedible chemical raw material, yet the government allows a certain amount in food. Isn't that going too far? Experts invited to the Department of Health press conference yesterday stated that, similar to dioxin or pesticide testing, while a detection value of zero is ideal, the reality is that even the most precise instruments have limits, and 2.5 ppm is already a very strict standard.
Dr. Yang Zhenchang, attending physician at the Clinical Toxicology Department of Taipei Veterans General Hospital, mentioned that considering the EU's standard for melamine release from food containers like melamine ware is 30 ppm, the Department of Health's food content detection standard of 2.5 ppm is indeed quite stringent.
He explained that if acute toxicity intensity is divided into extremely toxic, highly toxic, moderately toxic, and low toxicity, the allowable exposure level of melamine in rat experiments is 3161 mg per kilogram of body weight (at which point half of the test rats would die). For a 60 kg adult, this would mean consuming 189.7 grams at once to potentially be fatal, classifying it as a low-toxicity substance.
In terms of chronic toxicity, animal experiments also show that 90% of melamine is excreted from the body within a day of ingestion. In other words, melamine does not accumulate in the body and does not have genotoxic effects such as causing birth defects. The only concern is that continuous daily intake might lead to urinary tract stones.
Dr. Yang emphasized that according to the U.S. Food and Drug Administration's (FDA) daily allowable intake recommendation for melamine, it is 0.63 mg per kilogram of body weight. This figure is derived from rat animal experiments divided by 100 (as a tenfold safety factor is required for cross-species or individual differences).
Based on the above allowable intake and the detection standards announced by the Department of Health, a 60 kg adult could consume 15 kg of food containing 2.5 ppm melamine every day for 70 years without any issues.
Dr. Lin Bingxi, director of the Nephrology Department at Shin Kong Wu Ho-Su Memorial Hospital, stated that melamine has poor water solubility, which can lead to crystal formation during human metabolism, potentially causing stones. However, for nephrologists, as long as one drinks plenty of water or undergoes extracorporeal shock wave lithotripsy, stones are a completely curable condition.
Dr. Zheng Jihui and Dr. Yu Meijing from the Pediatric Nephrology Department, and Dr. Wang Damin and Dr. Chen Xiaowen from the Pediatric Urology Department at Linkou Chang Gung Children's Medical Center jointly stated yesterday that pharmacological and animal experimental evidence shows that melamine is almost entirely metabolized by the kidneys, with 90% excreted in urine within 24 hours of ingestion. This indicates that the kidneys clear melamine at a very fast rate. As long as it is not consumed in large amounts over a long period, there is no need for excessive concern. The best prevention is to develop habits of drinking plenty of water and urinating frequently.
Source: http:/ / times. hinet. net/ times……id=1758023& option=recreation