Abstract Food fraud encompasses economic fraud and can produce health problems for consumers, as well as conservation problems for the involved species. Nevertheless, few studies tested for mislabeling in restaurants. In this study, we tested for mislabeling of fish species in restaurants. We sampled 77 fish dishes from 53 different restaurants located in 9 different districts of Madrid, Spain. A short fragment of the 16S rDNA was employed for DNA amplification leading to species or genera identification. Results showed that 7 species or genera and almost 30% of the samples were mislabeled. Mislabeling was present in 37% of the sampled restaurants and in 71% of the sampled districts. Mislabeling was common and it was not correlated with a districts’ economic status (i.e. with the official average square-meter price of apartments). The analyses also showed that some species were more prone to be mislabeled than others.

中文翻译：

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16S rDNA 的扩增揭示了马德里餐馆中重要的鱼类标签错误

摘要 食品欺诈包括经济欺诈，会给消费者带来健康问题，也会给相关物种带来保护问题。然而，很少有研究测试餐馆中的错误标签。在这项研究中，我们测试了餐馆中的鱼类标签错误。我们从位于西班牙马德里 9 个不同地区的 53 家不同餐厅抽取了 77 种鱼类菜肴。16S rDNA 的一个短片段被用于 DNA 扩增，导致物种或属的鉴定。结果表明，7 个物种或属以及近 30% 的样本被错误标记。37% 的抽样餐馆和 71% 的抽样地区存在贴错标签。贴错标签很常见，而且与地区的经济状况（即公寓的官方平均平方米价格）无关。