Aflatoxin M1 Content and Mastitis-Causing Bacteria in Milk from Skopelos Dairy Goats Reared in Extensive and Intensive Farming Systems

This study assessed the impact of farming systems on aflatoxin M1 (AFM1) content and the prevalence of mastitis-causing bacteria in goat milk. A total of 233 milk samples were collected from two Skopelos goat farms-one intensive and one extensive farm-and analyzed for AFM1 content using a competitive ELISA. An additional 219 samples from goats suspected of subclinical mastitis were tested for bacterial prevalence with microbial culturing. The results showed that AFM1 concentration was significantly higher in the intensive farming system (7.76 ± 0.76 ng/kg) than in the extensive farming system (3.78 ± 0.79 ng/kg), though it remained below the legal limit of 50 ng/kg. The main effects of season and year were not significant, though higher levels of AFM1 were observed during winter. The interaction effects of season-farming system and year-season-farming system on AFM1 levels were significant. The prevalence of mastitis-causing bacteria varied by system, with <i>Streptococcus</i> spp. being more common in the extensive farming system, and <i>Staphylococcus aureus</i> was more frequently detected in milk samples from the intensive farming system. Binomial regression indicated that both the farming system and lactation stage significantly influenced <i>Streptococcus</i> spp. prevalence (<i>p</i> = 0.05; OR = 1.9 and 2.7, respectively). It is concluded that the farming system affects those quality parameters in goat milk.