Effect of season and farming system on aflatoxin M1 content and raw milk quality

The quality of raw milk plays an important role in the quality of dairy products. The current study was aimed to investigate the effect of season and farming system on aflatoxin M1 content and raw milk quality. For this reason, 600 samples were collected from 5 industrial farms and 5 milk collection centers of Khorramabad city during the summer and winter of 2017 (300 samples in each season). The contamination level of aflatoxin M1 was measured by high-performance liquid chromatography (HPLC) in 40 samples (4 samples from each farm). All samples were investigated in terms of acidity, density, protein, water percent, protein, fat and total bacterial count. The results showed the aflatoxin M1 in 5 samples (12.5%), was higher than the permitted level of National Standard (50 ng / ml). The amount of fat, protein, and density of samples collected in the winter was higher than those collected in the summer (P< 0.05). There was no significant difference between the aflatoxin M1 level in milk samples of industrial farms and milk collection centers. Moreover, the total bacterial count of 93% and 100% of the samples collected during summer and winter has exceeded the permissible limit specified in the National Standard, respectively, It could be concluded that in order to reduce the microbial load of raw milk, appropriate methods should be applied and the livestock breeders should be provided with the necessary training on how to milk and feed the animal. Moreover, the raw milk delivered to dairy factories should also be considered for aflatoxin M1.