Study of aflatoxins incidence in cow feed and milk in Serbia during 2013

Atypical weather and climate conditions during the spring and summer 2012th were assumed to be the main reason for the aflatoxins contamination of corn crops in Serbia. High humidity in spring, and summer temperatures above the average contributed to the increased possibility of mycotoxins occurance in cereals in the fields. As a consequence, at the begining of 2013th contaminated corn used for dairy cows diet had negative impact on the safety of cow milk. The routine laboratory control data revealed an increased content of aflatoxin M1 in milk samples. Large number of raw milk and various feedstuff samples were collected from February to April 2013th and were analysed for the presence of aflatoxin M1 (AFM1) and aflatoxin B1 respectively. The collected samples were a part of enhanced self-control plans of the large dairy farms. Quantitative competitive and sandwich types of ELISA tests were used for the screening analysis of the feed and milk samples. Confirmation of the positive results obtained by ELISA tests was performed by UPLC-MS/MS method. Out of 281 samples of complete mixtures for dairy cows, 67 samples (24%) contained aflatoxin B1 quantities higher than the MRL of 0,005 mg/kg [4]. Corn samples were also tested for the presence of aflatoxin B1 revealing contamination of 22% above the MRL (0.03mg/kg). Aflatoxin M1 content in the 934 positive milk samples ranged from 0,005- 1,25 μg/kg. The corresponding feed samples of sunflower meal, hay silage, corn silage and sugar beet pulp were screening negative, with the content of aflatoxin B1 less than 2 μg/kg. The main source of aflatoxins were corn samples, wholemeal and feed mixtures derived from contaminated corn. The contamination peak was during March 2013, when 65% of milk samples contained amounts of aflatoxin M1 higher than 0,05 μg/kg, and 13% of milk samples contained amounts higher than 0,5 μg/kg.