The aim of this study was to investigate the fungi and algae isolated from milk samples in dairy cows with clinical and subclinical mastitis from dairy farms around Mashhad, Iran. A total of 503 milk samples were obtained from 10 industrial dairy farms. All samples were simultaneously cultured on the surface of Blood agar, Macconkey agar, and Sabouraud dextrose agar supplemented with chloramphenicol. Fungi and algae were identified using phenotypic characteristics. In the examined samples, the bacterial contamination (338 out of 503 samples; 67.20%) was the most dominant followed by algae (93 out of 503 samples; 18.5%), filamentous fungi (32 out of 503 samples; 6.4%) and yeast fungi (26 out of 503 samples; 5.2%). Penicillium spp. (2.8%), Aspergillus spp. (2.6%), Cladosporium spp. (1.2%), Geotrichum spp. (0.4%), Ulucaladium spp., Scopolariopsis spp. and Alternaria spp. (0.2% each), Cryptococcus neofermenes (3%), Candida spp. (1%), Trichosporon spp. (0.8%) and Rhodoturula spp. (0.4%) were the filamentous and yeast fungi isolated from milk samples. Of the 93 algae isolated from 503 milk samples (18.5%), 83 (16.5%) samples were positive for Prototheca zopfii and 10 (2%) samples for Prototheca wickerhamii. According to the results of this study, yeast fungi, filamentous fungi and algae, especially Prototheca spp. are important contaminant factors in milk and contribute to clinical and subclinical bovine mastitis. Therefore, proper sanitation practices and management of dairy herds and judicious use of antibiotics is essential to control the fungal and algal contamination both in the environment and the breast.

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