Fish is among the most counterfeited foods. The differences between a cod fillet and a cheaper pangasius are barely visible to the naked eye. Suitable test systems such as real-time PCR are needed for fishery products to be identified without doubt.
Studies have shown for years that adulteration is widespread in the fish industry. Again and again, expensive fish species such as cod, sole or Bluefin tuna are substituted by cheaper species. The analysis of fish samples from restaurants in Brussels revealed that one out of three fish dishes wasn’t what is said on the menu, and a Canadian study has found that almost 50% of the fish samples were mislabeled (read more).
The problem with fish products is the long production chain from catching to filleting, processing and selling which often includes several intermediaries from different countries. Furthermore, some fish species are difficult to distinguish even for experts, and for many fish species, a variety of names are in use. In order to ensure transparent consumer information despite these difficulties, fishery products must be labeled with both the commercial name and the scientific name according to EU regulation No. 1379/2013. Fish processing plants and traders are obliged to ensure correct labeling and therefore need to perform appropriate analyses. The method of choice in this case is real-time PCR, a rapid and specific method for analyzing DNA sequences. In this video, Ronald Niemeijer explains the method in more detail: