Soaking in 20 times the amount of water is best for removing preservatives and bleaching agents

The Dragon Boat Festival is approaching, and health authorities have been announcing the results of random inspections of rice dumpling fillings. Among them, preserved radish and dried shrimp had the highest failure rate, mainly because the preservatives and bleaching agents exceeded the standard. The Taipei City Health Bureau has confirmed through experiments that soaking in 20 times the amount of water for 10 minutes is most effective in removing preservatives and bleaching agents.

Shrimp is a common filling for rice dumplings. The Health Bureau reminds people to soak it in 20 times the amount of water before use to remove preservatives and bleach. (Photo/taken from the Yangtao Culture website)

Xu Chaokai, director of the Health Bureau's laboratory, said that the preservative "benzoate" and the bleaching agent "sulfite" are both water-soluble and can be easily removed by soaking in water, but how much water is needed to be effective? The laboratory conducted the experiment by weighing 5 grams of preserved radish and dried shrimp, and soaked them in 5 times, 10 times and 20 times the amount of water for 10 minutes respectively. The results found that the removal effect was achieved after soaking in 5 times the amount of water; if soaked in 20 times the amount of water, it can even reach the qualified standard, which is the best effect.

Xu Chaokai explained that people can use a simple method to calculate 20 times the amount of water: for example, if you fill a cup of preserved radish with a rice cup, the amount of water to soak it is 20 rice cups; or if you regard the preserved radish in the pot as one layer, the amount of water to soak it must reach five layers.

Although soaking in water can indeed remove the residues of preservatives and bleach, the Department of Health still urges the public to choose reputable vendors or merchants when purchasing such products. It is best to buy products with complete packaging and labels, and soak and wash them in 20 times the amount of water before use to ensure the hygiene and safety of consumption.