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Aflatoxins in Milk: The Hidden Food Safety Challenge Dairy Systems Cannot Afford to Ignore

A mould toxin you cannot see, smell, or boil away is quietly moving from feed troughs into milk bottles across the world’s biggest dairy economies. Here is what the science says, what it means for India and the wider Global South, and what can actually be done about it.

India is the world’s largest milk producer, contributing more than a quarter of global output and underpinning the livelihoods of over 80 million rural households. Milk in India is not a discretionary purchase. It is a staple, a source of daily protein for children, and one of the few cash-generating assets available to smallholder families. Which is precisely why a contaminant that most consumers have never heard of deserves far more attention than it currently receives: aflatoxin in milk.

This is not a fringe concern raised by a handful of researchers. It is a documented, measurable, and recurring finding across dairy testing programmes in India and in many other milk-producing regions of the Global South. It is also, importantly, a solvable problem – but solving it requires understanding where the toxin comes from, why it is so persistent, and why the usual food-safety reflexes (boiling, pasteurising, “trusted brands”) do not make it disappear.

From Field to Glass: How a Fungal Toxin Ends Up in Milk

Aflatoxins are toxic compounds produced by two common fungi, Aspergillus flavus and Aspergillus parasiticus, which grow on cereal grains and oilseeds under warm, humid conditions. Of the various aflatoxins these fungi produce, Aflatoxin B1 (AFB1) is the most potent and the most frequently encountered in stored feed ingredients such as maize, groundnut cake, and cottonseed cake.

When a dairy animal eats feed contaminated with AFB1, a portion of the toxin is metabolised in the liver and converted into Aflatoxin M1 (AFM1), which is then excreted in milk. The International Agency for Research on Cancer (IARC) classifies AFB1 as a Group 1 carcinogen – the same category as tobacco smoke and asbestos – based on its demonstrated link to liver cancer. AFM1 is classified separately as a possible human carcinogen (Group 2B), reflecting its lower potency relative to AFB1 but still significant toxicological profile.

The detail that makes AFM1 a genuine food-safety concern, rather than a purely agronomic one, is its heat stability. Unlike many bacterial contaminants, AFM1 survives pasteurisation, boiling, and even ultra-high-temperature (UHT) processing largely intact. A review of AFM1 levels across raw milk, pasteurised milk, and infant formula confirms that standard thermal processing does not meaningfully reduce AFM1 concentrations once it is present. The contamination event has already happened by the time the milk reaches a kitchen, and no amount of household cooking can reverse it.

This means the entire control strategy for AFM1 has to sit upstream – in the feed, the storage shed, and the farm – rather than in the processing plant or the kitchen.

Why the Risk Runs Higher Across the Global South

Aflatoxin contamination is not unique to any one country. Exposure to aflatoxins is most prevalent across Southeast Asia, Sub-Saharan Africa, and parts of South America, regions that share a combination of climatic and structural factors that make contamination both more likely and harder to manage.

A growing body of climate research adds urgency to this picture. A comprehensive review of aflatoxin risk under climate change finds that rising temperatures and shifting rainfall patterns are expected to expand the geographic range and severity of aflatoxin contamination in staple crops, with modelling studies projecting that monetary losses in some maize-growing regions could increase several-fold within the next two decades. For a country whose dairy economy already runs on feed sourced from climate-exposed, rain-fed agriculture, this is not a distant scenario – it is a trend already underway.

What the Evidence Shows: A Look at the Numbers

The scale of the issue becomes clearer when looking at peer-reviewed surveillance data rather than anecdote. Several independent studies conducted across India in recent years have tested raw and bulk milk samples directly against both Indian and international regulatory limits.

That gap between standards is not a footnote. It shapes how the same data gets reported, and it has direct consequences for export markets, consumer trust, and how urgently a finding gets acted upon.

Two Standards, One Toxin: Why the Regulatory Gap Matters

The Codex Alimentarius Commission, the joint FAO-WHO body that sets international food standards, and India’s Food Safety and Standards Authority (FSSAI) both currently permit up to 500 ng/kg (0.5 µg/L) of AFM1 in milk. The European Union sets its limit ten times lower, at 50 ng/kg (0.05 µg/L), with an even stricter 25 ng/kg limit for infant formula and follow-on formula.

Source: FAO/WHO Codex Alimentarius documentation on AFM1 maximum levels and comparative regulatory analysis of AFM1 limits.

This gap matters for two reasons. First, it means a sample that would trigger a recall in the EU can pass comfortably under Codex and FSSAI thresholds – which is exactly what the Jammu study found. Second, as India’s dairy sector pursues export ambitions and as global supply chains become more interconnected, the gap between domestic and international thresholds becomes a competitive and reputational issue, not just a technical one. Closing this gap, even gradually, would align India’s dairy quality assurance with the markets it increasingly wants to serve.

The Cost Nobody Sees on the Farm

Most discussions of aflatoxin focus on the consumer end of the chain, but the first and often largest economic impact lands on the farm itself – usually invisibly. Chronic, sub-acute aflatoxin exposure in dairy animals has been associated with reduced feed intake, impaired immune function, decreased reproductive performance, liver dysfunction, and measurably lower milk yields, even at exposure levels well below those that cause visible illness.

A review of aflatoxin toxicity in dairy cows notes that these effects are frequently subclinical – meaning a farmer sees lower output, a missed heat cycle, or a herd that seems “off,” and attributes it to genetics, season, or general management, without ever suspecting feed contamination as the cause. The economic damage compounds quietly across an entire lactation cycle before anyone thinks to test the feed.

At a macro level, the numbers are substantial. A comprehensive review of worldwide aflatoxin contamination estimates that aflatoxin-related losses in Sub-Saharan Africa alone amount to roughly USD 450 million annually – around 38 percent of all global agricultural losses attributed to aflatoxin contamination. Separately, a well-documented 2013 contamination episode in Serbia led to product recalls and a sharp drop in milk purchases, with losses to the farm-level dairy sector estimated at over EUR 96 million across the following two years. These figures illustrate how quickly a feed-quality issue can escalate into a sector-wide economic shock once it surfaces in finished milk.

The Human Health Stakes, Especially for Children

The health implications of AFM1 exposure extend well beyond the cancer-risk classification that headlines tend to focus on. Because milk is disproportionately consumed by children – often as a primary protein source in the first years of life – and because children are more vulnerable per unit of body weight to toxin exposure, the public health stakes are weighted heavily toward the youngest consumers.

Research from Sub-Saharan Africa has linked chronic dietary aflatoxin exposure to childhood growth faltering and stunting. A study estimating the health burden of aflatoxin-attributable stunting in low-income African countries found that aflatoxin exposure accounted for an average of 16 percent of the disability-adjusted life years (DALYs) lost to stunting in the populations studied. The proposed mechanisms include impaired immune function, increased susceptibility to infection, and reduced absorption of micronutrients – effects that compound during the critical growth window of early childhood and have been linked to longer-term consequences for cognitive development.

This is the context in which the comparatively low awareness of AFM1 among consumers becomes a genuine public health gap. A toxin that is invisible, untasted, and unaffected by boiling – present in a food that is specifically given to children for its nutritional value – is exactly the kind of risk that requires upstream, systemic intervention rather than consumer vigilance.

Closing the Gap: From Reactive Testing to Proactive Feed Systems

The good news is that aflatoxin contamination in milk is not an intractable problem. It is, fundamentally, a feed quality and supply chain management problem, and the interventions that work are well documented in the scientific literature.

1. Systematic feed testing as standard practice

The single highest-leverage intervention is testing feed ingredients – particularly maize and oilseed cakes – for aflatoxin before they enter the ration. This needs to move from an occasional, reactive activity to a routine part of procurement across organised and semi-organised dairy supply chains. Investment in drying infrastructure, moisture monitoring, and proper warehouse management at the point of feed aggregation can prevent contamination from ever reaching the farm.

2. Scientifically validated mycotoxin binders

Where contamination cannot be entirely prevented, feed additives known as mycotoxin binders can reduce the proportion of AFB1 that converts to AFM1 in milk. A network meta-analysis of 28 studies comparing different binder types – including hydrated sodium calcium aluminosilicate (HSCAS), bentonite clay, and yeast cell wall preparations – found that several formulations meaningfully reduced AFM1 concentration in milk following an AFB1 challenge, with bentonite and HSCAS among the more consistently effective options. These binders are not a substitute for clean feed, but they provide a genuine additional layer of protection, particularly during high-risk seasons.

3. Fresh, traceable nutrition systems

The third lever is structural: reducing how long feed ingredients sit in storage before being consumed. Aflatoxin accumulation is fundamentally a function of time, temperature, and moisture acting on stored grain. Feed that is grown, harvested, and consumed within a short cycle has a substantially smaller window in which fungal contamination can develop, compared with grain that may sit in a warehouse or on a farm floor for weeks or months.

This is one of the reasons that controlled-environment fodder production – including hydroponic green fodder systems – has attracted interest as part of a broader risk-reduction strategy. It is worth being precise here: a hydroponic system does not make contaminated seed safe. If the seed grain entering a hydroponic unit is itself carrying Aspergillus or existing aflatoxin load, sprouting it does not remove that risk, and the warm, humid conditions inside a fodder unit can, without proper protocols, themselves support fungal growth. The benefit of fresh fodder systems is realised only when they are paired with robust seed quality assurance at intake – tested, clean seed grown on a short cycle, rather than untested seed grown in a controlled environment.

A Challenge Shared Across the Global South

While this article draws heavily on Indian data because India’s scale and surveillance density make it one of the better-studied dairy systems in the developing world, the underlying problem is not India-specific. The same combination of warm climates, maize- and groundnut-cake-based rations, fragmented smallholder supply chains, and informal feed markets characterises much of dairy production across East and Southern Africa, parts of Southeast Asia, and segments of Latin America.

For institutions and dairy enterprises operating across these geographies, the lesson from the Indian data is transferable: aflatoxin risk in milk correlates closely with feed sourcing practices, storage duration, and climate exposure – all of which are manageable through the same set of interventions, regardless of which country’s regulatory limit applies. Shunya’s work on distributed, fresh fodder infrastructure and documented production protocols is built around exactly this principle: that feed quality and traceability are infrastructure problems first, and food safety outcomes follow from how that infrastructure is designed.

Key Takeaways

• Aflatoxin M1 (AFM1) in milk originates from Aflatoxin B1 in feed, primarily maize and oilseed cakes contaminated by Aspergillus fungi during growth or storage.
• AFM1 survives pasteurisation, boiling, and UHT processing – control has to happen at the feed and farm level, not in the kitchen or processing plant.
• Peer-reviewed surveys in Punjab and Jammu found 56.2% and 75.8% of milk samples respectively exceeded the EU’s AFM1 limit, though most remained within the more permissive Codex/FSSAI limit.
• The EU’s AFM1 limit (50 ng/kg) is ten times stricter than the Codex and FSSAI limit (500 ng/kg) – a regulatory gap with real implications for export readiness and consumer protection.
• Chronic low-level exposure causes subclinical losses on dairy farms – reduced yield, fertility, and immunity – that often go undiagnosed as feed contamination.
• In children, chronic aflatoxin exposure has been linked to growth stunting, with estimates attributing up to 16% of stunting-related DALYs in some African populations to aflatoxin.
• Feed testing, validated mycotoxin binders, and fresh, short-cycle nutrition systems with strong seed quality assurance are the three evidence-based levers for reducing risk.

Building Toward Safer Milk, One Feed Decision at a Time

Aflatoxin contamination in milk is a solvable problem, but only if it is treated as the systemic, feed-chain issue that the evidence shows it to be. For a dairy sector as large and as economically important as India’s – and for the many dairy economies across the Global South that share its risk profile – closing the gap between current practice and what the science recommends is not just a food safety upgrade. It is an investment in the productivity, income security, and long-term resilience of the millions of households this sector supports.