Numerous e-commerce platforms in mainland China have been found to sell bullfrogs with excessive antibiotic residues. Some samples were detected to have values reaching 5.09 times the current food safety standards set by the Chinese Communist Party, while another sample was found to contain the metabolite of the veterinary drug furazolidone.
According to a report by “The Paper” on August 3, testing on bullfrog products from various e-commerce platforms revealed the issue of excessive drug residues in multiple samples.
Among them, a bullfrog product from Duoduo Mai Cai (a community group-buying platform under Pinduoduo) had an enrofloxacin detection value of 509 micrograms per kilogram. This value is calculated by adding enrofloxacin and its metabolite ciprofloxacin, far exceeding the limit of 100 micrograms per kilogram as stipulated by China’s food safety standards.
A bullfrog product sold by Pinduoduo’s “Monkey Brother Bullfrog Farm” had a fluoroquinolone detection value of 278 micrograms per kilogram; enrofloxacin was detected at 211 micrograms per kilogram, both exceeding the limit of 100 micrograms per kilogram.
Another Pinduoduo store selling bullfrogs was found to contain the metabolite of furazolidone, with a level of 3.42 micrograms per kilogram. Furazolidone is strictly prohibited in bullfrog farming, and its metabolite should not be detected in bullfrog products.
Similar issues have arisen before. In March 2025, the non-profit organization “Natural Field” tested 51 batches of bullfrogs, of which 21 batches exceeded the standard for antibiotic residues, accounting for over 40%.
Investigators visiting bullfrog supply chains in Fujian, Guangdong, and Jiangsu found that processors categorize bullfrogs into three grades.
The head of a processing company in Shantou, Guangdong, stated that the company classifies bullfrogs into export, “antibiotic-free,” and “regular” categories with decreasing prices respectively. Export products have the best quality with almost no antibiotic residues. “Antibiotic-free” does not mean complete absence of residues but that they do not exceed the limits set by China’s food safety standards; the “regular” category is more prone to exceeding the limits of drug residues.
The company head mentioned that the “regular” category accounts for about half of their supply, mainly sold to wholesale markets and takeaway stores. When facing inspections, they only need to prepare a small amount of “antibiotic-free” products to pass.
Another company head mentioned that their company can provide customers with samples labeled as “antibiotic-free” for testing. If a customer buys regular products but requests a testing report, the company can provide a “qualified” report for display, although the corresponding batch may not actually meet the standard.
Another supplier’s head admitted that the company does not track the withdrawal period of purchased bullfrogs and does not conduct third-party testing batch by batch. They typically perform third-party testing once a year and reuse the qualified report throughout the year.
Behind the bullfrog supply chain lies a huge consumer market. The “China Bullfrog Industry Report” shows that in 2025, mainland China’s bullfrog breeding amounted to about 600,000 tons, with over 40,000 bullfrog-themed restaurants and an industry value of approximately 48 billion RMB.
Lu Liping, Deputy Chief Pharmacist at the Fourth Hospital of Zhejiang University School of Medicine, stated that consuming food with excessive enrofloxacin residues over a long period or in large amounts may cause gastrointestinal discomfort, headaches, dizziness, liver damage, increase the risk of bacterial resistance, and potentially affect the cartilage development of fetuses and children.
She explained that the metabolite of furazolidone can bind with animal tissue proteins, which are difficult to remove through regular cooking and may pose risks of carcinogenicity, teratogenesis, and mutation.
An article on the science popularization platform Guokr.com mentioned that thorough cooking cannot reliably eliminate drug residues. Prolonged consumption of bullfrogs with excessive drug residues may harm health, and resistant bacteria and genes may propagate along the food chain.
The related news has sparked discussions among netizens. Some expressed concerns, with one saying, “I used to eat bullfrogs for their tenderness, but after seeing the news, my heart is trembling.” Others questioned why the issue of drug residues in aquatic products has been repeatedly highlighted despite long-term attention.