The effect of the technological steps used in making and during the storage at 6°C for 15 days of concentrated yoghurt (Labneh) from reconstituted skim milk being spiked with veterinary residues, namely ciprofloxacin at concentration 100 ppm to study the behavior of this residues. In addition, the effect of the technological factors on residues stability during storage period was studied. Samples were analyzed for total solids, pH, organic acids namely formic, pyruvic, lactic and acetic acids and drug residues recovery at time intervals after 3, 7, 10 and 15 days. The obtained results revealed that the presence of the ciprofloxacin residues had no effect on the chemical parameters of concentrated yoghurt (Labenh) namely total solids, pH and the recoveries of organic acids. On the other hand, data indicated that this drug showed high thermal stability by separation using HPLC under the conditions of this study. The recovery of ciprofloxacin residues after 15 days of storage period may indicate that the reaction between drug residues and protein is chemical reaction.
Thus, the application of HACCP system in milk production and processing must be taken into consideration to insure a safe product for the consumer.