What our latest peer-reviewed study in the Journal of the Hellenic Veterinary Medical Society tells us about managing feed risks in modern dairy systems.
Aflatoxins present a challenging issue related to climate, feed management, and food safety. They are produced by toxigenic strains of Aspergillus in maize and other feed materials, especially when heat and moisture stress occur. When these contaminated feeds enter dairy rations, some of the aflatoxin is transferred into milk as aflatoxin M1. It is a molecule subject to strict maximum residue limits in the EU and very low tolerance from consumers and regulators alike.
In everyday farm practice, however, aflatoxins often remain an abstract concern. Nutritionists discuss “risk factors”, veterinarians worry about chronic health effects, and dairies observe milk tanker samples. Nonetheless, the quantitative relationships between specific feedstuffs and the final milk delivered to the plant are not always clear.
Our latest peer-reviewed article in the Journal of the Hellenic Veterinary Medical Society addresses this exact gap. It offers a data-driven analysis of how aflatoxin levels in key feed components relate to those in cow’s milk on actual farms in Northern Greece.
What the study actual did
The research team collected a large set of paired feed and milk samples from commercial dairy farms in Central Macedonia and Thessaly during 2021–2022. In total, the dataset includes:
- Corn grain
- Cottonseed
- Maize silage
- Total mixed rations (TMR)
- Fresh cow’s milk
All samples were analysed using ELISA methods to determine aflatoxin content. The aim was precise: to assess the covariance and correlation between aflatoxin levels in each feed component (and in the TMR) and the aflatoxin M1 levels found in bulk tank milk. Pearson correlation coefficients and scatter plots were employed to illustrate the strength and linearity of these relationships.
This is not a purely theoretical modelling exercise. It is an effort to measure, under Greek field conditions, how much the mycotoxin issue in the silo and feed store “shows up” in the milk tank.
Key findings in simple language
First, the reassuring part: across all farms and sampling points, aflatoxin concentrations in milk did not exceed the maximum permissible EU limit. Even when aflatoxin levels in certain feed ingredients were measurable, the final milk remained within the legal safety margin.
However, within that “safe” band, the relationships were clear and statistically significant:
- Higher aflatoxin levels in corn grain were associated with higher aflatoxin levels in milk.
- The same was true for cottonseed and for the total mixed ration as it is finally delivered at the feed bunk.
- The correlations were linear and robust: as aflatoxin concentration in these feeds increased, aflatoxin M1 in milk rose accordingly, without erratic outliers or signs of non-linear behaviour.
In other words, the study confirms in a real-farm dataset what toxicologists and nutritionists have been arguing for years: the milk aflatoxin problem is, to a large extent, a feed management problem- particularly around high-risk ingredients such as corn and cottonseed and the way they are combined in the TMR.ncerning high-risk ingredients like corn and cottonseed and how they are combined in the TMR.
Why this matters for veterinarians and nutritionists
For field veterinarians, aflatoxins often manifest as part of a broader range of subclinical health issues: immune suppression, fertility problems, and increased susceptibility to disease. The nutritionists represent an additional constraint when designing cost-effective rations. The evidence from this study offers a common quantitative language for both. nutritionists,
Three practical implications stand out:
- Targeted monitoring beats generic testing. Rather than testing everything lightly, it makes more sense to focus sampling and analytical budgets on the ingredients and TMRs that statistically drive milk aflatoxin levels. Corn grain, cottonseed and the final TMR deserve priority in routine mycotoxin monitoring plans.
- Ration design is part of food safety. The study underscores that the way we construct the TMR is not only a matter of energy, protein, and fibre balance, but also of how much aflatoxin risk we carry forward into the tank. When a high-risk ingredient is included at substantial inclusion rates, mitigation strategies (binders, sourcing policies, storage management) become a core food-safety decision rather than a “nice to have”.
- “Below the limit” does not mean “irrelevant”. All milk samples were compliant with EU limits, yet the correlations were strong. That means day-to-day variation in feed contamination still produces measurable differences in milk aflatoxin levels. For dairies building premium brands, establishing export reputations, or meeting stricter private label standards, these internal variations matter.
Broader lessons for the dairy chain
At a system level, this work indicates a more integrated approach to mycotoxin control:
- For farmers, it reinforces the importance of agronomic and storage practices around maize, as well as careful procurement, drying, and preservation of cottonseed and other susceptible ingredients.
- For cooperatives and feed companies, it supports the case for shared monitoring schemes, supplier auditing and data-driven risk maps that reflect regional and seasonal patterns.
- For dairies, it justifies investment in upstream technical support: helping their supplying farms manage feed risk may be more cost-effective than dealing with rejected consignments or downstream reputation damage.
Finally, the study is also a small example of what the agricultural knowledge and innovation system (AKIS) is supposed to look like in practice: universities, practitioners and the industry working together to generate knowledge that is both scientifically solid and directly usable on farms.
Where we go from here
Aflatoxins will not disappear from dairy farming. Climate volatility, pressure on feed costs and the expansion of maize in many regions mean that the underlying biological risk is here to stay. What can change, and must change, is how we manage that risk.
By quantifying the links between specific feeds, the TMR and the milk tank under Greek conditions, this research provides a firmer basis for designing monitoring plans, ration strategies and advisory services that are truly evidence-based. It also opens the door for more granular work: seasonal analyses, farm typologies, and the integration of mycotoxin data into broader farm-level decision tools.
For those interested in the full methodology, statistical outputs and detailed results, the article is available open-access in the Journal of the Hellenic Veterinary Medical Society.
→ Read the full paper in the Journal of the Hellenic Veterinary Medical Society