Occurence of antimicrobial residues in milk and labneh consumed in Lebanon

ABSTRACT

Antimicrobials are administered in livestock for different uses leading to milk contamination and several undesirable effects. Because there is a lack of surveillance of antimicrobial residues (AMRs) in milk and dairy products in Lebanon, this study aims to determine the occurrence of AMRs in 90 Lebanese samples of milk and labneh (concentrated yoghurt). Multi-residue screening methods with suitable sample preparations were applied to detect 71 AMRs in milk and labneh, respectively, using LC-MS/MS. Of the total number of samples, 71% was contaminated with AMRs and (fluoro)quinolones and macrolides were the most detected families. Additional confirmation tests proved that 6.7% of the milk samples were non-compliant for the macrolides tilmicosin, tulathromycin and spiramycin. Moreover, some labneh prepared from contaminated milk samples was analysed to determine the fate of AMRs during the manufacturing process. The results showed that some AMRs could be concentrated, eliminated or degraded, based on their physicochemical characteristics.

KEYWORDS:

• Antimicrobial residues
• milk
• dairy products
• multi-residue control
• LC-MS/MS

Acknowledgments

This paper is dedicated to the memory of Professor Mohamad Al Iskandarani (passed away March 4, 2021), for his valuable contribution. We also wish to thank the institutions “PHC-Cèdre France-Liban”, “Région Bretagne” and “Rennes Métropole” having partially supported financially this project.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the French Ministry of Agriculture and Food (MASA BAI 2022, 2023) under Grants [numbers 22-37 and 23-41] and by the French Ministry of Foreign Affairs under PHC-Cèdre Grant [number 41963PG].