Why do national standards repeatedly appear so lenient

Recently, the CCTV Finance Channel program "Is It True" broadcast a report about strawberries, saying that 8 samples of strawberries randomly purchased by the program team's reporters in Beijing were all detected to contain two pesticides, chlorothalonil and acetochlor. The program said that the content of the former met national standards, while the latter is not registered in the national strawberry residue standards, but compared with EU standards, some strawberries exceeded the limit by 6 times. Experts said that the United States has classified acetochlor as a B2 carcinogen, and long-term consumption of food with acetochlor residues may lead to poisoning by acetochlor metabolites and has carcinogenicity.

What is acetochlor? Can strawberries still be eaten safely? Acetochlor is a commonly used herbicide, first invented by the United States, and many countries use it, including the United States. Acetochlor is not unique to China.

Compared with US standard regulations, China's regulations on the use of acetochlor are stricter, allowing it only in brown rice, corn, soybeans, peanuts and rapeseed, and the residue limits are also lower.

However, neither China nor the United States includes strawberries in the scope of permitted use of acetochlor. If it really was used, then that would be an illegal act and should be severely cracked down on.

Doubtful points about acetochlor being detected in strawberries

However, there are also some doubtful points in this report about strawberries being detected with excessive acetochlor.

First, acetochlor is a pre-emergence soil-sealing herbicide, generally used before crops sprout, and acetochlor has a very short degradation period, usually just a few days, so by the time strawberries ripen there would generally not be very high residues.

Second, acetochlor also causes some harm to strawberry seedlings. If too much is used, it will also kill the strawberry seedlings. Farmers can hardly use large doses during planting, otherwise it would also kill the strawberry seedlings and directly affect the harvest.

Third, most strawberry cultivation now uses ground mulching film, mainly for fear that strawberries will mold after touching the ground, reducing quality and yield. Another effect of mulching film is to suppress weed growth. Basically, weeds under the film cannot grow, and there is almost no need to apply herbicides.

Therefore, detecting such a high level of acetochlor in strawberries is a very strange matter, and the possibility of error cannot be ruled out.

Do we need to worry about the safety of strawberries?

The oral acute toxicity LD50 (median lethal dose) of acetochlor in rats is 2.59 grams. Even for the strawberries with the highest detected value (0.367 mg/kg), to reach the poisoning dose, one would have to eat more than 7 tons at once.

In fact, the B2 carcinogen classification of acetochlor was the standard used by the EPA (US Environmental Protection Agency) before 1996. The current classification of acetochlor is “suggestive evidence of carcinogenic potential, but not sufficient research to confirm it.”

In the media report, the highest detected acetochlor residue value was 0.367 ppm. The report said that eating such strawberries with excessive pesticide residues “in large amounts over the long term” would cause poisoning and cancer. But exactly how large an amount is required?

China's standard considers the ADI (acceptable daily intake) of acetochlor to be 0.02 mg/kg bw. According to this reference value, a 60 kg adult would have to eat 3.27 kg of such strawberries every day to exceed the safe range.

Under the stricter European assessment (the EU does not allow the use of acetochlor), EFSA (European Food Safety Authority) considers the ADI of acetochlor to be 0.0036 mg/kg bw/day. A 60 kg adult would still have to eat 580 grams of strawberries every day to exceed this range.

So before worrying about whether it is unsafe, first look at exactly how many strawberries you eat every day.