Detection of ciprofloxacin residues in milk by sensitive and rapid methods is of great interest due to its use in the treatment of dairy livestock health. Current analytical approaches to antibiotics detection, are laboratory-based methods and they are time-consuming and require trained personnel. To cope this problem, we propose an assay, based on fluorescence polarization principle, able to detect the presence of ciprofloxacin in diluted milk sample without any pre-treatment. The proposed method is based on the use of ciprofloxacin-protein conjugate labeled with near infrared fluorescence dye, which upon binding to specific antibody causes an increase of the fluorescence polarization emission signal. The developed assay allows for the detection of ciprofloxacin at a concentration of 1ppb, which represents an amount lower than the maximum residual limit (MRL) of ciprofloxacin in milk, as set by the European Union regulation (100 ppb).The antibiotics treatment plays a crucial role in dairy livestock health 1 . It is being used for therapeutic purposes as well as for improving breeding efficiency. However, this treatment can leave residues of antibiotics in foods of animal origin (milk and meat), and consequently an increase of the human exposure to antibiotics 2 . While assessing the usage of antibiotic residues, the exceptional use of such drugs was legally considered 3 . Hence, the risk of the presence of antibiotic residues in milk and dairy products could increase in case that a required elimination period of them in food is not properly defined.Antibiotic residues in milk and dairy products present detrimental consequences on the consumer health, causing disturbances in the intestinal flora as well as allergic reactions that could lead to anaphylaxis 4 . Moreover, antibiotic residues might increase microbial resistance, a major health risk 5 . Among anti-bacterial agents used for the management of infections in dairy livestock, ciprofloxacin, belonging to the fluoroquinolone class, is the common antibiotic used in case of pulmonary, urinary and digestive infections 6 . However, ciprofloxacin could cause hypersensitivity in humans 7 . Due to the importance of considering the presence of ciprofloxacin in milk, a residue surveillance of anti-microbial presence is crucial to support food-farming practices, upraising consequently the food safety level. It is to be noted that the maximum residual limit (MRL) for ciprofloxacin in milk has been fixed at 100 ppb (Council Regulation EEC/2377/90). In Lebanon, few studies have investigated the presence of antibiotic residues in milk [8][9][10] . A recent study showed that ciprofloxacin and oxytetracycline are mostly found antibiotics in milk in Lebanon (personal communication).Currently, laboratory-based methods, such as liquid chromatography-mass spectrometry (LC-MS), high performance liquid chromatography (HPLC) [11][12][13] and microbiological assays 14 are the common used approaches for ciprofloxacin detection. These methods have different restrictions that make the...

Background and Aim: Cheese is considered an essential component of the Lebanese table, however, several foodborne illnesses have been reported due to cheese consumption. This study aimed to assess the microbiological quality and the occurrence of antibiotic and pesticide residues in two traditional Lebanese cheeses, Akkawi and Baladiyeh. In addition, drug resistance of isolated pathogens from the cheese samples was evaluated. Materials and Methods: Fifty Akkawi and Baladiyeh cheese samples were obtained in duplicate from 37 different commercial brands in supermarkets and shops from various regions of Lebanon. Samples of different weights were either individually vacuum packed or soaked in brine unpacked where it was placed in plastic bag after being purchased. Samples were homogenized to determine antibiotic and pesticide residues using liquid and gas chromatography coupled to mass spectrometry, and microbiological evaluation was performed according to the International Organization for Standardization reference analytical methods. The disk diffusion method was used to determine the susceptibility of these isolates to antibiotics. Results: Microbiologically, 17% of Akkawi and 14% of Baladiyeh samples were found to be non-conforming. The bacterial isolates (n = 29) were tested for their susceptibility to 11 different antibiotics commonly prescribed in the Lebanese community or used for treating infections caused by Gram-negative bacteria and listeriosis. Each isolate was found to be resistant to at least three antibiotics. Liquid and gas chromatography coupled to mass spectroscopy analysis showed the absence of pesticide residues in all samples. However, sulfamethazine antibiotic residue was found in 14% of the samples. Conclusion: The results suggest that the cheese samples tested could cause foodborne illnesses due to the detection of pathogenic bacteria and are a public health concern due to the presence of antibiotic residues and the transmission of multidrug-resistant organisms.