A sensitive and robust electrochemical cholinesterase-based sensor was developed to detect the quaternary ammonium (QAs) biocides most frequently found in agri-food industry wash waters: benzalkonium chloride (BAC) and didecyldimethylammonium chloride (DDAC). To reach the maximum residue limit of 28 nM imposed by the European Union (EU), two types of cholinesterases were tested, acetylcholinesterase (AChE, from Drosophila melanogaster) and butyrylcholinesterase (BChE, from horse serum). The sensors were designed by entrapping AChE or BChE on cobalt phthalocyanine-modified screen-printed carbon electrodes. The limits of detection (LOD) of the resulting biosensors were 38 nM for DDAC and 320 nM for BAC, using, respectively, AChE and BChE. A simple solid-phase extraction step was used to concentrate the samples before biosensor analysis, allowing for the accurate determination of DDAC and BAC in tap water with limits of quantification (LOQ) as low as 2.7 nM and 5.3 nM, respectively. Additional assays demonstrated that the use of a phosphotriesterase enzyme allows for the total removal of interferences due to the possible presence of organophosphate insecticides in the sample. The developed biosensors were shown to be stable during 3 months storage at 4 °C.

A sensitive and reliable electrochemical biosensor for the detection of benzalkonium chloride (BAC) and didecyldimethylammonium chloride (DDAC), the most commonly used disinfectant biocides in the agri-food industry, is described. Acetylcholinesterase from Drosophila melanogaster (DM AChE) and butyrylcholinesterase from horse serum (BChE) were immobilized by entrapment in a photocrosslinkable polymer on the surface of carbon screen-printed electrodes. Preliminary tests conducted in phosphate buffer showed limits of detection (LODs) of 0.26 µM for BAC using the BChE-based sensor and 0.04 µM for DDAC using the DM AChE sensor. These performances comply with the European regulation for dairy products, which sets a maximum allowable concentration of 0.28 µM for biocides. However, when tested directly in milk samples, a dramatic decrease in the sensitivity of both sensors towards BAC and DDAC biocides was reported. To overcome this problem, a simple liquid–liquid extraction was necessary prior to biosensor measurements, ensuring that the biosensors met European regulatory standards and provided an unbiased response.

A sensitive and robust electrochemical cholinesterase-based sensor was developed to detect the quaternary ammonium (QAs) biocides most frequently found in agri-food industry wash waters: benzalkonium chloride (BAC) and didecyldimethylamonium chloride (DDAC). To reach the maximum residue limit of 2.8 10-8 M imposed by the European Union (EU), two types of cholinesterases were tested, acetylcholinesterase (AChE, from Drosophila melanogaster) and butyrylcholinesterase (BChE, from horse serum). The sensors were designed by entrapping AChE or BChE on cobalt-phthalocyanine-modified screen-printed carbon electrodes. The limits of detection (LOD) of the resulting biosensors were 3.8 10-8 M for DDAC and 3.2 10-7 M for BAC, using respectively AChE and BChE. A simple solid phase extraction step was used to concentrate the samples before biosensor analysis, allowing the accurate determination of DDAC and BAC in tap water with limits of quantification (LOQ) as low as 1.3 10-9 M and 5.3 10-9 M, respectively. The biosensor was shown to be stable during 3-months storage at 4°C.

Aunque los antimicrobianos son grandes aliados en producción animal, su uso masivo ha contribuido a la aparición de antibiorresistencias. Además, cuando los periodos de supresión no se respetan, sus residuos pueden llegar a la cadena alimentaria, provocando toxicidad directa, alergias y/o disbiosis en la microbiota intestinal de los consumidores.Puesto que España y Francia son los mayores productores de carne en la UE y están entre los principales consumidores a nivel mundial, el objetivo de nuestro estudio fue investigar la presencia de antimicrobianos en carne comercializada en el área transfronteriza España‑Francia. Se recogieron 5.357 muestras de carne de diferentes especies animales en España (Zaragoza, Bilbao y Logroño) y Francia (Toulouse y Perpignan), que se analizaron por un método de cribado (Explorer®+QuinoScan®, Zeulab S.L., Zaragoza, España), obteniendo 194 muestras positivas, que se analizaron por cromatografía UPLC‑QTOF para su confirmación. Los análisis cromatográficos revelaron presencia de residuos en 30 muestras, aunque solo 5 de ellas (0,093 % de las muestras iniciales) fueron no‑conformes de acuerdo a la legislación. Análisis posteriores sugirieron que esta divergencia entre el cribado y la confirmación se debe a la presencia de metabolitos biológicamente activos derivados de los antimicrobianos originales, no identificados por el método dirigido UPLC‑QTOF, generando la inhibición del test Explorer®. Así, aunque las técnicas cromatográficas detectan el compuesto marcador indicado por la legislación y son los métodos de elección para control oficial de antibióticos en alimentos, sus metabolitos pueden escapar al monitoreo, lo que sugiere que los test biológicos son más adecuados para proteger la salud de los consumidores.