Lebanon's agricultural sector, known for its diverse crop and livestock production, faces challenges in the international market due to the presence of chemical residues and contaminants in its food exports. Recent rejections of these exports have raised global concerns about food safety, increasingly seen as vital for public health and economic prosperity. This review focuses on examining scientific studies about the levels of various chemical residues including pesticides, and veterinary drugs and contaminants like mycotoxins, and polycyclic aromatic hydrocarbons, and heavy metals in Lebanese food products. Findings indicate that these residues and contaminants often exceed both the maximum residue limits (MRLs) and maximum limits (MLs) set by the Codex Alimentarius and the European Union. The review concludes with recommendations for reducing these contaminants and residues to enhance Lebanon's food safety and quality, aligning with international standards, and mitigating the risk of export rejections.

A new multi-residue method based on solid-phase extraction (SPE) with centrifugation was developed for determination and quantitation of 67 pesticides in water samples. Two SPE cartridges were tested: Chromabond C18 and Oasis HLB. Parameters that influence the extraction efficiency such as the eluent volume, the sample loading volume, the addition of organic solvent to water sample, sorbent drying and elute concentration were optimized. The innovation of this work was the examination of the use of a centrifugation technique in both the drying and elution steps. When combined with centrifugation, the volume of the elution solvent was reduced to 2 mL and the time for sorbent drying decreased also to 10 min under vacuum. Under the optimized conditions, this method showed good recoveries higher than 65% - 68% for the 67 analyzed pesticides using the C18 and HLB cartridges with relative standard deviations lower than 9.7% - 12.3%. Limits of quantification were between 2 and 20 ng.L–1. The simplicity of the described method, use of less of organic solvent, short procedure time, and good recoveries demonstrate the advantages of this environmentally friendly approach for routine analysis of numerous samples.

Nitro compounds were usually determined electrochemically using the mercury drop with DPP technique. An alternate way to toxic mercury is the increasing use of the bismuth electrode as thin film electrodeposited on glassy carbon or copper for example, or as bulk bismuth disc. In the present paper several nitrocompounds were investigated: mononitrophenols, dinitrophenol, nitrobenzoic acid, nitrobenzaldehyde and a well known pesticide, parathion, which has a nitro group in para position on a phenyl cycle. Bulk bismuth electrode was a disc (cross section of a rod of 5mm diameter embedded in Teflon (R)) polished with silicon carbide disc (P2400) and sonicated to remove any abrasive particle. The supporting electrolyte was the acetic buffer (pH 4.7), which was found suitable for all these compounds. Using cathodic sweep differential pulse voltammetry, it was noticed that according to the position of the nitro group on the cycle, the peak potentials might range between -300 to -750mV vs. SCE. Limits of detection (LOD) and limits of quantification (LOQ) were determined for each compound whose response for increasing concentration was linear in the similar to 3-50 mu molL(-1) whatever the considered molecule. Adsorptive differential pulse voltammetry was found very efficient to determine parathion, because this molecule adsorbs on bismuth at -0.2V vs. SCE. Bulk bismuth electrode was compared to the hanging mercury drop electrode and led to an identical behaviour.