2. Analytical methods
2.1. Extraction of ADF from food matrices
A wide variety of food products contain azo dyes as colorants. As a consequence, there is no generally accepted/standard method for their extraction in laboratories. Nevertheless, most extraction procedures follow a common path involving the release of desired analytes from their matrices, followed by removal of extraneous matter and a suitable extraction method (solid–liquid or liquid–liquid extraction) (Thompson and Trenerry, 1995 and Wu et al., 2013).