Aflatoxins in Dairy Feed: The Risk Quality Teams Cannot Inspect Away

What Aflatoxins Are, and Why Dairy Watches Them So Closely

Aflatoxins are toxic secondary metabolites produced by fungi, chiefly Aspergillus flavus and Aspergillus parasiticus, that colonise cereal grains and oilseed cakes under specific conditions: moisture stress in the field, delayed harvest, or humid storage. Across India and other tropical and sub-tropical dairy belts, maize, groundnut cake and cottonseed cake, staple ingredients in compounded cattle feed, are especially exposed to this risk, as a recent review of aflatoxins in livestock feed documents in detail.

Aflatoxin B1 (AFB1) is the most toxic member of this family. It is associated with hepatotoxic, immunosuppressive and carcinogenic effects in both animal and human studies, which is why regulators worldwide treat it as the aflatoxin of primary concern in feed and food safety programs.

What makes AFB1 a dairy-specific concern is metabolic transfer. Once ingested, a fraction of the AFB1 present in feed is converted by the cow’s liver into aflatoxin M1 (AFM1), which is then excreted directly into milk. Published estimates of this feed-to-milk carryover vary with milk yield, feed intake and other physiological factors. A review of carryover studies published in Toxins puts the average transfer rate at roughly 1 to 2 percent, rising to 6 percent or more in high-yielding animals, while a field monitoring study of high-yielding dairy cows recorded a mean carryover of 8.79 percent across matched feed and milk samples, with individual outliers above 30 percent.

In practice, this means aflatoxin control in feed is not a feed-quality question alone. It is a milk-safety question, and one that begins well before the animal is fed.

Two Standards, One Widening Gap

Regulators have responded to this transfer risk differently across geographies, and the difference is instructive for any quality team benchmarking its own specifications.

Under Indian Standard IS 2052:2009, the Bureau of Indian Standards caps aflatoxin B1 at 20 µg/kg (ppb) in compounded cattle feed. The Food Safety and Standards Authority of India applies a far tighter limit, 0.5 ppb, to aflatoxin in food intended for direct human consumption, a gap that exists precisely because of the feed-to-milk carryover risk described above.

The European Union has gone a step further and written that carryover risk directly into its feed regulation. Under Directive 2003/100/EC, general compound feed is capped at 20 µg/kg AFB1, similar to the Indian limit. But for compound feed specifically intended for dairy cattle, sheep and goats, the EU sets a considerably tighter ceiling of just 5 µg/kg, a quarter of the general limit, explicitly because of AFM1 carryover into milk. The EU’s own limit for AFM1 in finished milk is 0.05 µg/kg.

For quality leaders benchmarking their own feed specifications, this is a useful marker. Compliance with a general national feed standard is not the same as compliance with the tighter standard that regulators, once they examined the biology closely, decided dairy animals specifically need.

How Common Is Contamination in the Field?

Aflatoxin contamination in feed grain is not a rare event confined to isolated outbreaks. It shows up consistently across independent surveys, and in patterns that repeat across tropical and sub-tropical dairy geographies well beyond India, from maize belts in Eastern Kenya to specialised dairy farms in Eastern Ethiopia, wherever maize, groundnut and cottonseed cake move through humid harvest and storage conditions.

Within India specifically, a national-scale survey of 2,074 maize samples, cited in subsequent aflatoxin detection research, found that roughly one in four samples exceeded the country’s safe aflatoxin threshold. Feed samples tested at the National Dairy Development Board’s laboratory in Anand, drawn specifically because they were suspected of contamination, averaged 68 µg/kg of aflatoxin B1, more than three times the BIS limit. A 2023-24 survey of compound livestock feeds in Andhra Pradesh found that cattle feed carried the highest incidence of contamination among compound feed categories, with groundnut cake and maize the most affected raw ingredients. A household-level study spanning four districts and 160 households across India found that, depending on district, 30 to 80 percent of households had at least one aflatoxin-contaminated grain sample in store, again concentrated in groundnut and maize.

None of this reflects negligence on the part of any single actor in the chain. It reflects the physics and biology of a supply chain in which grain travels through weeks or months of harvesting, drying, storage, transport and distribution before it becomes feed, and every additional day in warm, humid conditions widens the window for fungal growth.

What an Independent Lab Found in Nutri Ankurit Feed

Against this backdrop, a recent laboratory finding on Shunya Agritech’s Nutri Ankurit Feed (NAF) is worth examining closely.

An independent analysis conducted by SGS India, one of the world’s leading testing, inspection and certification companies, examined NAF for all four regulated aflatoxins: B1, B2, G1 and G2. Every one of them came back below the laboratory’s limit of quantification (LOQ), meaning the analytical method used could not detect aflatoxins above its own sensitivity threshold. Total aflatoxins were measured at less than 2 µg/kg.

The distinction between “compliant” and “below the limit of quantification” is not a technicality. Many feed samples across the industry are compliant with the 20 µg/kg limit while still carrying detectable, quantifiable contamination. A result below the LOQ places NAF at the very low end of what current analytical methods can even measure, a materially different, and materially safer, category of result.

Why Production Method May Explain the Difference

The obvious question is why. The likely answer has less to do with chemistry and more to do with how the feed is made.

Conventional feed ingredients typically spend weeks, sometimes months, moving through harvesting, drying, storage, transport and distribution before reaching an animal. Every additional day under warm, humid conditions increases the opportunity for fungal colonisation and toxin production. This is precisely the storage-and-handling window that the surveys cited above consistently identify as the point of contamination.

Nutri Ankurit Feed follows a different production pathway. It begins with carefully screened cereal grain, moves through a controlled hydroponic growing environment, and reaches the farmer as fresh feed within roughly seven days. The crop is never subjected to prolonged warehouse storage, nor does it pass through the multiple handling stages typical of conventional feed supply chains. Controlled protocols, daily harvesting and rapid consumption together create conditions that are inherently less favourable to fungal growth than the storage-heavy pathway conventional feed usually travels.

It would be scientifically incorrect to claim that hydroponic production alone guarantees the absence of aflatoxins. Feed safety still depends on the quality of incoming grain, production hygiene, environmental control and operational discipline; a single laboratory report, however clean, is a data point and not proof of causation. What can reasonably be said is that a well-managed, short-cycle production system removes several of the environmental windows in which aflatoxin-producing fungi typically establish themselves, and that this SGS result is consistent with that expectation.

What This Means for Feed Safety Programs at Scale

For a quality leader managing feed safety across a large, multi-tier sourcing network, three implications follow.

First, acceptance testing at the plant gate, however rigorous, is a control of last resort. It catches contamination after the exposure window has already closed; the feed has been produced, stored and often partly consumed by the time a certificate of analysis is reviewed.

Second, the choice of feed production model is itself a food-safety lever, not merely a nutrition or cost decision. A production system that compresses the time between harvest and consumption, and removes multiple storage and handling stages, structurally reduces the number of opportunities contamination has to occur. This holds whether the dairy operation sits in India, in Sub-Saharan Africa, or in any tropical or sub-tropical geography where maize, groundnut and cottonseed cake form the backbone of the ration. Shunya Agritech’s own comparative analysis of livestock feed options looks at this trade-off in more detail across cost, nutrition and safety.

Third, benchmarking against the general national feed standard may understate real risk. Regulators who have examined the biology closely, as the European Union has, apply a materially tighter standard to feed destined for dairy animals specifically. Large dairy companies with export ambitions, or with quality programs designed against global rather than purely domestic benchmarks, may find it useful to hold their own suppliers to that tighter line rather than the general one.

Perhaps the most encouraging aspect of the SGS report on Nutri Ankurit Feed is not that it complied with regulatory limits. Many feeds achieve compliance. What stands out is that the measured aflatoxin concentrations fell below the laboratory’s own ability to quantify them, placing this sample at the very low end of contamination typically reported for livestock feed anywhere in the world.

As dairy sectors across the global south increasingly compete on productivity, milk quality and international food safety standards, feed safety will draw more scientific attention, not less. The conversation is shifting from “how much nutrition does this feed provide” to an equally important question: how safe is that nutrition, and how far upstream does that safety actually begin?

Sometimes the most significant food safety innovation is not something added to a feed. It is what has been engineered out of the supply chain that produces it. In the case of Nutri Ankurit Feed, one of those absences appears to be a contaminant that has challenged dairy nutrition across the tropics for decades. For quality leaders, farmers and consumers alike, that absence may prove to be one of the most valuable attributes the feed has to offer.