Introduction: Despite the beneficial effects of antibiotics in the treatment of infectious diseases, their residuals in food such as meat, milk and its transmission to human body have harmful effects. The purpose of this study was to monitor the residual antibiotics in raw and pasteurized milk of Maragheh and Bonab townships by four-plate test method (FPT).

Materials & methods: For this purpose, 7 Dairy industries in Maragheh, 7 Dairy industries in Bonab, 4 traditional dairies in Maragheh, 5 traditional dairies in Bonab, a unit of milk processing plant in Maragheh, and a unit of milk processing plant in Bonab were chosen randomly. 25 milk samples were collected at 4 repeated different times of the remaining four antibiotics and were studied by plate method (FPT).

Findings: 7 (94/24%) samples of raw milk dairy industries of Maragheh, 15 cases (47/53%) samples of raw milk dairies industry of Bonab, 6(5/37%) samples of raw milk dairies of traditional type in Maragheh 4 (20%) samples, and Bonabtraditionaldairymilk1 (25%) samples of pasteurized milk contaminated Maragheh antibiotic residues were detected and Bonab pasteurized milk samples were found as negative. The results showed that the maximum residual antibiotic in the penicillin and macrolid groups (p>0.05) and the least residual antibiotic was confirmed in enrofloxazin group.

Discussion & conclusions: According to Iranian milk consumption per capita, these rates of contamination affect considerable part of population especially vulnerable groups like children, pregnant women, the elderly, and patients. This research shows the necessity of legislative and food inspecting organizations to control and minimize these contaminations.