Dietary exposure to tetracycline residues through milk consumption in Iran

The abundant use of tetracycline antibiotics in veterinary medicine may result in the presence of their residues in milk at unsafe concentrations that can adversely affect public health. The aim of the current study was to evaluate the risk of tetracycline residue (TET) intake via milk consumption amongst different age groups of human consumers in Iran.

To quantify the drug residues, HPLC analysis was performed under isocratic conditions using UV detection at 355 nm. Milk consumption patterns were determined using a recent nutrition survey in Iran.

The average concentration of total TETs in milk was determined to be 252.41 μg/kg, which is approximately 2.5 times greater than the maximum residue limit (MRL) set by codex. Of the four different tetracycline antibiotics analyzed, oxytetracyclin had the highest share (86 %) of the determined contamination.

Daily exposure to TETs through milk using an average data on milk consumption was estimated to range from 58-62 μg. but, distribution based exposure to TETs in milk appeared as 0-99.3 μg per day.

Risk characterization of dietary exposure to TETs residue via milk intake in different age groups showed that considering the standard dietary recommendation that advices on two servings of milk per day (480 ml), consumers may receive 7-30 % of the determined ADI via bovine milk consumption.