Antibiotic residues and aflatoxin M1 contamination in milk powder used in Tehran dairy factories, Iran

BACKGROUND: The presence of aflatoxin M1 (AFM1) andantibiotic residues in milk and milk products is a public healthconcern. Milk and milk powder have the potential forintroducing AFM1 and antibiotic into human diet. In recentyears, milk powder has been used on a large scale in dairyfactories. Consequently, antibiotic residues and aflatoxincontamination control in these products has gained importance.OBJECTIVES: The aim of this survey was to determine the levelof β-lactam and tetracycline antibiotic residues and also AFM1contamination of milk powder used in Tehran dairy factories.METHODS: During 12 months (September 2011 to September2012), 240 samples of milk powder were collected from tenTehran dairy factories. All samples were analyzed for thepresence of AFM1 using ELISA technique. In addition,antibiotic residues were determined by BetaStar Combo test, arapid assay for both β-lactam and tetracycline antibiotics.RESULTS: The samples depicted positive results i.e. 30% and17.5% for β-lactam and tetracycline antibiotics, respectively.Also, AFM1 was found in 155 cases (64.6%) with an averageconcentration of 29.85 ± 18.99 ng/ L. CONCLUSIONS:The resultsshowed the milk powder used by dairy factories is safe in respectof AFM1 contamination and antibiotic residues in Tehran.