Antimicrobial residue assessment in 5, 357 commercialized meat samples from the Spain-France cross-border area: A new approach for effective monitoring

Although antimicrobials are valuable allies in animal production, their extended use has led to unexpected threats associated with the emergence and propagation of antimicrobial resistance. Moreover, when withdrawal periods in food-producing animals are not observed, antimicrobial residues can access the food chain, causing direct toxicity, allergies, and/or intestinal microbiota dysbiosis in consumers. Given that Spain and France are the largest meat producers in the EU and also count among the top consumers of meat, our study''s aim was to investigate the presence of antimicrobials in commercialized meat purchased in the Spain-France cross-border area (POCTEFA region). 5, 357 meat samples were collected from different animal species and a variety of different retailer types in Spain (Zaragoza, Bilbao, and Logroño) as well as in France (Toulouse and Perpignan). Meat samples were analysed by a screening method (Explorer®+QuinoScan®), yielding 194 positive samples, which were further evaluated by UPLC-QTOF (Ultra Performance Liquid Chromatography-Quadrupole Time of Flight) for confirmation. Chromatographic analyses found antimicrobial residues in 30 samples, although only 5 of them (0.093% of initial samples) were non-compliant according to the current legislation. Further studies suggested that this mismatch between screening and confirmatory analyses might be due to the presence of biologically active metabolites derived from degradation of antimicrobials that were not identified by the targeted UPLC-QTOF method, but which might play a decisive role in the inhibition of the biological Explorer® test. Although chromatographic techniques detect the marker compounds determined by European and national regulations, and although they are the methods selected for official control of antimicrobials in food, certain unknown metabolites might escape their monitoring. This thus suggests that biological tests are the most adequate ones in terms of ideal consumer health protection

Ultra-sensitive biosensor based on genetically engineered acetylcholinesterase immobilized in poly (vinyl alcohol)/Fe–Ni alloy nanocomposite for phosmet detection in olive oil

International audienceAn ultra-sensitive screen-printed biosensor was successfully developed for phosmet detection in olive oil, based on a genetically-engineered acetylcholinesterase (AChE) immobilized in a azide-unit water-pendant polyvinyl alcohol (PVA-AWP)/Fe-Ni alloy nanocomposite. Fe-Ni not only allowed amplifying the response current but also lowering the applied potential from 80 mV to 30 mV vs Ag/AgCl. The biosensor showed a very good analytical performance for phosmet detection, with a detection limit of 0.1 nM. This detection limit is lower than the allowable concentrations set by international regulations. In addition to the good reproducibility, operational and storage stability, the developed biosensor was successfully used for the determination of phosmet in olive oil samples without any laborious pre-treatment. The phosmet recovery rate was about 96% after a simple liquid-liquid extraction

Oxovanadium–salen and –salan complexes as effective labels for electrochemical immunosensing: a case study for estradiol detection

International audienceOxovanadium complexes are presented as new labels for the development of electrochemical immunosensors. The concept was successfully applied to the accurate detection of estradiol, an emerging environmental pollutant, at concentrations ranging from 4 ng L−1 to 5 μg L−1

Acetylcholine detection at micromolar concentrations with the use of an artificial receptor-based fluorescence switch

An inclusion complex between water-soluble p-sulfocalix[n]arene (C-n, n = 4, 6, 8) and the chromophore trans4-[4-(dimethylamino)styryl]-1-methylpyridinium-p-toluenesulfonate (D) formed the basis for a highly sensitive sensor for the selective detection of neurotransmitter acetylcholine (ACh). Formation of the [C-n center dot D] complex (K-a = similar to 10(5) M-1) was accompanied by a drastic increase (up to 20-60-fold) in the chromophore relative quantum yield and by a large hypsochromic shift of the emission band maximum. The observed optical effects are fully reversible: ACh displaces the chromophore molecules from the calixarene cavity as shown by the reappearance of the free chromophore emission band. Formation and dissociation of the complex were studied by fluorescence, H-1 NMR, and UV-vis absorption spectroscopies. The [C-n center dot D] complex is capable of sensing ACh selectively in solution at sub-micromolar concentrations. Immobilization of monocarboxyl p-sulfocalix[4]arene (C-4m) on an oxide-containing silicon surface is in keeping with its properties, such as chromophore binding and the ability of the immobilized inclusion complex to detect ACh. The unique [C-m center dot D] complex optical, switching paves the way for application in ACh imaging and optoelectronic sensing