Can you tell whether the “oyster” in delicious oyster omelette comes from Taiwan or Vietnam? In recent years, Vietnamese oysters, which belong to the Portuguese oyster (scientific name: Magallana angulata) species and are sold at a lower price than Taiwanese oysters, have accounted for more than half of the total imported oysters. In order to prevent confusion, the Fisheries Laboratory of the Ministry of Agriculture held a press conference on the 6th to announce a newly developed oyster origin identification technology. By analyzing 14 elements in a total of 595 oyster samples from the two places, the identification rate reached 97.3%.
The Fisheries Department stated that it will jointly develop an inspection mechanism with the Food Safety Office of the Executive Yuan and the Food and Drug Administration of the Health and Welfare Bureau in the future. If there is any fraud, penalties will be imposed according to the Food Safety Act.
Imports of Vietnamese oysters raise concerns about fraud and food safety
Local oyster production has declined in the past decade, from 36,000 metric tons in 2010 to 16,700 metric tons in 2022. Oyster imports continue to rise, from 1,931 metric tons in 2019 to 5,217 metric tons in 2022 and 4,525 metric tons in the first nine months of 2023.
The period from October to February every year is the off-season for domestic oyster production, and it is also the peak season for imported oysters.
Vietnam is currently China’s largest oyster importer, rising from 201 metric tons in 2019 (accounting for 10.4% of total imports) to 2023 metric tons in 2022 (accounting for 57.9% of total imports). The import volume far exceeds that of Japan, South Korea, the United States or Other countries. The price of Taiwanese oysters is about 160 yuan per catty, while the price of Vietnamese oysters is about 120 yuan. Since the oysters from both places are of the same species, they are difficult to distinguish with the naked eye, causing suspicion among unscrupulous traders.
Food safety issues are also a concern for consumers. Since 2021, the Food and Drug Administration of the Ministry of Health and Welfare has received 14 reports of non-compliance with regulations on the microbial content and heavy metal content of imported Vietnamese oyster meat.
The most difficult thing is to confirm the origin of “Vietnamese oysters”
In order to protect consumers, the Ministry of Agriculture’s Water Testing Institute obtained 380 domestic oyster samples from 5 administrative regions in Taiwan including Changhua, Yunlin, Chiayi, Taiche and Penghu from June 2022 to September 2023, and North Vietnam ( Halong Bay and Vinh City), China-Vietnam (Da Nang), South Vietnam (Nha Trang), etc. collected 215 samples. After using DNA identification technology to confirm that they were Portuguese oysters, they then used inductively coupled plasma mass spectrometry (ICP-MS) technology to analyze Based on the contents of 14 elements in clean meat samples, including cadmium (Cd), chromium (Co), copper (Cr), iron (Fe), etc., a database of 1,785 characteristic element analyzes was established.
Since the edible tissue of oysters accumulates various elements in their growth and habitat environments, this characteristic can reflect the place of origin and serve as an important basis for identification of origin, with an identification rate of up to 97.3%.
Cai Huijun, researcher and leader of the aquatic products processing group, said that the most difficult part of the entire testing process is to confirm the true origin of the oyster samples. “In Taiwan, you can find samples at the farms, but in Vietnam, you have to confirm that what they are selling is Even if they are grown purely in Vietnam, there are still fake ones.” After the authorities find shucked oysters from genuine sources in the Vietnamese market, they will pack them and freeze them and send them back to the laboratory for testing.
Less than 40% of Taiwan’s oyster farmers have non-mandatory labels for traceability
Zhang Jinyi, director of the Water Testing Institute, said that the new technology has not yet been used on the market and is only used for sample testing. Since there was no technology in the past that could identify the origin of oysters, there have been no cases of fines for violating labeling. The Fisheries Department has also provided guidance to domestic oyster operators in the past to introduce aquatic product traceability systems. So far, a total of 702 households have passed production and sales records and aquatic product traceability labels, accounting for more than 35% of the total oyster farmers.
Regarding issues such as “If you don’t label, you won’t be caught”, or products with traceable labels are more expensive, Zhang Jinyi said that the labeling system is not mandatory, but “I believe people are willing to pay more to buy food with guaranteed origin.” It means that the new technology can also be applied to other aquatic products in the future.
This article is reproduced with permission from the “Environmental Information Center” (Original text: Ministry of Agriculture’s new technology helps “Taiwan Oyster” verify its authenticity and those who pretend to be fake will be fined)