On July 8, according to Lychee News, the "Brothers Lobster Xianhe Store" in Nanjing had a rating of 4.9 on food delivery platforms with over 1,000 monthly sales. However, according to insider information, this internet-famous store was using oxalic acid, commonly known as "lobster washing powder," to clean crayfish. Undercover reporters discovered that employees at the store were cleaning crayfish in a corridor using a solution that emitted a sour odor, next to which white powder labeled "Oxalic Acid AR Analytical Pure" was placed. The cleaning employee admitted they had already cleaned about 150 jin (75 kg) of shrimp that day. Reporters observed over several days that the store did not change the cleaning solution or add new oxalic acid. The same pool of liquid, reused, emitted a strong sour smell. The store's processing volume was very large, cleaning lobster twice daily, in the morning and afternoon, with each session cleaning over 100 jin (50 kg). Although the store's main hall was under renovation, kitchen operations were unaffected, and processed lobster continued to be sold through delivery platforms. During a joint inspection by local authorities, faced with evidence provided by reporters and empty oxalic acid bottles on site, staff insisted they used tap water for cleaning. Law enforcement determined the kitchen had serious hygiene issues and ordered suspension for rectification. The store (self-destructed) over 100 jin (50 kg) of problematic lobster. Currently, market supervision departments are further investigating the case and have notified delivery platforms to remove the store. According to Jiangsu News, an expert from the National Processed Food and Food Additives Quality Inspection and Testing Center stated in an interview regarding this incident that a 2019 reply from the General Office of the State Administration for Market Regulation clearly stated: "Oxalic acid is an allowed auxiliary component for food disinfectants in China, but auxiliary components cannot be used alone as disinfectants in the absence of main active ingredients. Meanwhile, from the perspective of the crayfish processing process, using oxalic acid as a disinfectant lacks (process necessity)." The reply from the General Office of the State Administration for Market Regulation also clearly stated that China's "Food Safety Law" (stipulates) that food production and operation should comply with food safety standards, and the detergents and disinfectants used should be safe and harmless to humans. If oxalic acid is used as lobster washing powder, it combines with calcium to form a precipitate that the human body cannot absorb and must (excrete). If the amount is particularly large, it may burden the kidneys and, in severe cases, cause kidney stones, posing health risks to consumers. According to a related 2019 report by The Beijing News, a food engineering (Ph.D.) explained that oxalic acid comes in food-grade and industrial-grade, differentiated by impurity control during production. Industrial-grade oxalic acid cannot be used in food cleaners. If too much oxalic acid residue remains after cleaning crayfish, it can cause a sour and astringent taste. Additionally, oxalic acid is corrosive and harmful to the person washing the shrimp. Furthermore, in the report, reporters searching for "lobster washing powder" on e-commerce platforms found that several (merchant customer service) claimed their products did not contain oxalic acid and used food-grade citric acid. However, reporters found that some products were clearly labeled as 99.5% industrial oxalic acid powder for cleaning toilets, tiles, and rust removal, with no mention of shrimp cleaning, yet customer service said, "Others use it; just slowly adjust the ratio of water to oxalic acid. Shrimp vendors and restaurant owners buy it." (By Shen Xiaoge)