Presence of nitrofurans and their metabolites in gelatine

Abstract

Following the detection of semicarbazide (SEM) in gelatine by Italian Authorities, at levels exceeding by three times the reference point for action (RPA) of 1 μg/kg, set out by Commission Regulation (EU) 2019/1871 for nitrofurans and their metabolites, the European Commission mandated EFSA to investigate the available sources of nitrofurans and their metabolites in gelatine. European Commission also asked EFSA to provide approaches that would distinguish SEM occurring due to illegal treatment with nitrofurazone from SEM produced during food processing. The literature indicates that SEM, both free and bound to macromolecules, could occur also in food products such as gelatine, during food processing, arising from the use of disinfecting agents and/or from reactions of various food components and, therefore, SEM cannot be considered as an unequivocal marker of the abuse of nitrofurazone in animal production. It is recommended to investigate in more detail which processing conditions lead to the formation of SEM in gelatine during its production and what levels can be found. One potential approach to distinguishing between SEM from nitrofurazone and SEM from other sources in food products, such as gelatine, might be based on determining the ratio of bound:free SEM in a sample of gelatine. However, whether the ratio of bound:free SEM would unequivocally distinguish between SEM arising from nitrofurazone abuse or from other sources still needs to be demonstrated.

Keywords: SEM; analytical approach; gelatine; illegal treatment; nitrofuran metabolites; nitrofurans; nitrofurazone; semicarbazide.

Figure 1

Putative formation of nitrofurazone‐derived protein‐bound residues from (i) reduction of the nitro‐group and generation of an open chain cyano‐metabolite (left) and (ii) release of the side chain (SEM) under acid hydrolysis (right). Unstable metabolites are between square brackets (modified from Hoogenboom et al., 2002)

Figure 2

Flowchart of the process for pigskin gelatine extraction (modified from Chung et al., 1990)