Is ractopamine toxic? What is the upper limit of safe dosage? Can the human body metabolize it? Analysis of the exclusive interview with Professor Zhao Mingwei

Interviewed Expert/Zhao Mingwei (Associate Professor of Department of Biotechnology, Chung Yuan University)

1. What is ractopamine? What are its current uses?

Ractopamine was originally developed for use as an asthma drug, but during clinical trials it was found that its drug efficacy was not as expected and it could not be marketed through relevant regulations, so it was developed as a feed additive for the livestock industry.

During the 20th century, the U.S. public health unit found that people in this country had a high risk of cardiovascular disease, which may be related to the saturated fat in fat meat. Most Americans eat beef, pork, and turkey as their staple food, so they must find appropriate methods. , reduce people’s cholesterol and triglyceride problems.

In experiments in breeding institutions, it was found that ractopamine can increase the protein in meat and reduce the fat ratio. Therefore, by adding ractopamine to feed, the protein ratio of beef, pork, and turkey is increased, and the nutritional content of edible meat is adjusted. Currently, ractopamine is only allowed to be used as a feed additive.

2. Does ractopamine have toxic effects on organisms?

The United States has conducted preclinical trials and human trials on ractopamine. The experimental results show that at extremely high concentrations, ractopamine can indeed cause adverse reactions.

From the data of human experiments, when “injecting” 5 mg of ractopamine, there will be reactions such as hand shaking, palpitations, and arrhythmia, but there is no fatal danger. In fact, there are no reports of deaths caused by high doses of ractopamine in any studies.

However, scientific research must set extreme values ​​to define the scope of reasonable use of a substance. Although adverse reactions do occur under high doses of ractopamine, reasonable and safe usage standards can be defined.

3. Can ractopamine be excreted from the body through metabolism?

Ractopamine has water-soluble properties, which means that like vitamin C, it is metabolized very quickly in the body. On average, the human body can metabolize 95% of ractopamine within 24 hours. That is, because it is easily metabolized, ractopamine is not as effective as expected as an asthma drug.

4. Is ractopamine a safe food additive?

Ractopamine has no concerns about toxicity at legal and safe doses. When discussing the safety of additives, we must return to their chemical nature. As mentioned above, ractopamine has water-soluble characteristics, is easily metabolized by the human body, and has a low accumulation amount. When the accumulation risk is not high, toxicity concerns naturally fall into a lower range.

5. Is ractopamine easy to accumulate in the internal organs of animals?

Ractopamine does accumulate in the guts of animals. In proportion, the amount accumulated in the internal organs is 4 times higher than that in the muscles. Therefore, when international regulations stipulate the residual amount of ractopamine, the limit for visceral parts is 40ppb, and the limit for muscle parts is 10ppb. To avoid excessive intake, the recommended limit for eating offal is 1/4 of muscle. However, Taiwan does not open the import of animal offal.

6. Is there a safe intake limit for ractopamine?

For pork containing ractopamine, the residue level must be less than 10 ppb to meet the standard. Converted into the ADI “maximum daily intake”, adults per meal are limited to 1 microgram per kilogram, and the amount that a 60-kg adult can consume in one meal It is 60 micrograms, which is approximately equivalent to 6 kilograms of pork; pork liver or internal organs are 0.25 micrograms per kilogram (the residue standard is 4 times that of meat). Ractopamine will only exceed the standard if you consume more than 1.5 kilograms of animal offal per meal.

In addition, it must be emphasized that ractopamine is water-soluble. Take the popular Taiwanese delicacy “pork liver soup” as an example. The ractopamine remaining in the pig liver will dissolve into the water (Editor’s note: Taiwan currently does not allow the import of animal offal containing ractopamine. ), so the calculation standard requires drinking all 1.5 kilograms of pork liver and soup before it exceeds the standard.

7. Will the liberalization of ractopamine affect food safety issues in Taiwan?

Ractopamine does not pose any food safety risks under legal regulations. It is not a chemical that can cause serious harm like poisons such as plasticizers or dioxin, and even toxic substances have safety regulations. Generally speaking, as long as the content of ractopamine is within a safe range, it will not cause physical effects, and it will not cause neurotoxicity to consumers as rumored on the Internet. This has not been seen in animal experiments and clinical trials. situation.

Opening up the import of U.S. pork containing ractopamine will have a greater impact on the trade level, including whether it will affect the livelihood of pig farmers. As a free trade market, Taiwan’s openness to meat imports corresponds to the segmentation of the consumer market. Some ethnic groups prefer meat with more fat, while others prefer meat with lower fat. It depends on whether the public pays for it. On the contrary, if “Laizhu” is not open to imports, whether it will affect other aspects of trade cooperation between Taiwan and the United States requires careful consideration by the government and the people.

From the perspective of international trade, when meat is exported, the exporting country must submit inspection reports for antibiotics, animal drugs, bacterial counts, and ractopamine residues, etc., and only if it meets the importing country’s specifications is it allowed to be imported. Therefore, the most important key is whether the competent authorities use scientific data as the control standard to ensure that the amount of ractopamine residues in meat products is within specifications. Then the opening of “Lai Zhu” is basically the same as that of “Lai Niu”. The residual amount All are limited to 10 ppb, which can ensure food safety to the greatest extent.