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

## TL;DR

This study found that intensive farming systems had higher levels of a harmful toxin in goat milk, while extensive systems had more bacteria linked to udder infections.

## Contribution

The study is the first to compare AFM1 levels and mastitis-causing bacteria in goat milk from intensive and extensive farming systems.

## Key findings

- AFM1 levels were significantly higher in intensive farming systems but remained below legal limits.
- Streptococcus spp. was more prevalent in extensive systems, possibly due to hand-milking practices.
- Lactation stage and farming system both significantly influenced bacterial prevalence.

## Abstract

Mycotoxins are toxic substances produced by molds on feed. Mycotoxins ingested by dairy animals are transformed into aflatoxin M1 (AFM1) and pass onto milk, degrading its quality and safety. Pathogens such as Streptococci and Staphylococci contaminate milk through mastitis or poor milking practices. Understanding the factors influencing the presence of mycotoxins and pathogens in milk is crucial for improving dairy quality and ensuring consumer safety. This study investigated the effects of the farming system (intensive vs. extensive), year, and season on AFM1 levels as well as the impact of the farming system on the prevalence of mastitis-causing pathogens. The results revealed that AFM1 content was significantly higher in the intensive farming system, potentially due to feeding and storage practices. Interactions between year and season had a notable impact on AFM1 levels, which may reflect variations in climate conditions and animal management strategies over time. Milk AFM1 levels in both farming systems remained below legal thresholds. The prevalence of bacterial pathogens was significantly influenced by both the farming system and the stage of lactation. Streptococcus spp. appeared more frequently in the extensive system, potentially due to hand-milking practices. Its presence increased as lactation progressed, possibly due to heightened udder susceptibility in the later stages.

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 Streptococcus spp. being more common in the extensive farming system, and Staphylococcus aureus 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 Streptococcus spp. prevalence (p = 0.05; OR = 1.9 and 2.7, respectively). It is concluded that the farming system affects those quality parameters in goat milk.