Mycotoxin Binders and Deactivators: Clays, Yeast Cell Walls, Enzymes, How They Work and How to Choose

Mycotoxin binders and deactivators are feed additives that adsorb mycotoxins in the gut or transform them into less toxic metabolites, and the EU Register lists only bentonite, fumonisin esterases and one bacterial strain in functional group 1m. Each of these 1m entries names one toxin group and fixed target animals: bentonite 1m558 names aflatoxin B1 at a maximum of 20 000 mg/kg complete feed, the fumonisin esterases name fumonisins at legal minimum contents measured in entry-specific units (for example 10 U/kg for 1m03i), and the strain DSM 11798 names trichothecenes at a minimum of 1.7 x 10^8 CFU/kg.

"Toxin binder" is the market term, and it covers more than the EU group. Yeast cell walls, clinoptilolite, sepiolite and activated charcoal are all sold as binders, yet none holds an EU 1m entry, and in the US no regulation, approval or GRAS notice grants any product a mycotoxin claim. This page sets out what each tool is, how it works, which toxin and species it fits, which inclusion figure is a legal limit and which is a trial result, and what to check before buying.

Every value on this page is compiled from the EU authorising acts, the EU Register of Feed Additives, EFSA opinions, the eCFR and named peer-reviewed studies, checked on 3 November 2026; the sources and checks are described in the methodology.

What Is a Mycotoxin Binder?#

A mycotoxin binder is a feed additive that reduces the absorption of mycotoxins from the gut, either by adsorbing them or, as a deactivator, by converting them into less toxic metabolites. In EU law the group is functional group 1m, a functional group of category 1 among the five feed additive categories of Regulation (EC) No 1831/2003. Its legal name is "substances for reduction of the contamination of feed by mycotoxins", and its definition reads "substances that can suppress or reduce the absorption, promote the excretion of mycotoxins or modify their mode of action".

EU functional group 1m and the US classification#

In the EU, mycotoxin binders form functional group 1m of category 1 technological additives, added by Commission Regulation (EC) No 386/2009 of 12 May 2009. A feed additive is a substance, micro-organism or preparation other than feed material and premixtures that is intentionally added to feed or water to perform a listed function (Article 2(2)(a) of Regulation (EC) No 1831/2003). A 1m entry is the only EU legal route to a mycotoxin claim. Category 1 authorisations are generic, so a 1m entry names a substance and its conditions, never a holder.

In the US, no CFR section, new animal drug approval (NADA) or GRAS notice grants a mycotoxin-binding claim to any product. Clays sold as toxin binders appear only as GRAS substances or food additives for anticaking or carrier use: bentonite under 21 CFR 582.1155 and hydrated sodium calcium aluminosilicate (HSCAS) under 21 CFR 582.2729. The same bentonite therefore carries an aflatoxin B1 condition in its EU 1m entry and no toxin claim at all in the US.

The word "binder" has a second meaning in feed. Mycotoxin binders are not to be confused with pellet binders, which hold feed pellets together and belong to EU functional group 1g; some clays, such as sepiolite and clinoptilolite, hold only that binder or anticaking entry and no 1m entry.

Mycotoxins in feed and why binders exist#

Mycotoxins in feed cut feed intake by 12 % and weight gain by 14 % in broilers, and by 18 % and 21 % in growing pigs, according to two meta-analyses by Andretta and colleagues (Poultry Science 2011; Animal 2012). The broiler meta-analysis pooled 98 papers and 37,371 birds; the pig meta-analysis pooled 85 articles and 13,196 pigs. Effects differ by toxin: deoxynivalenol cut pig feed intake and gain by 26 % each, aflatoxins cut pig intake by 16 % and gain by 22 %, and ochratoxins cut broiler intake by 17 % and gain by 20 %. The toxins come mainly from maize and other cereals contaminated by moulds in the field or in storage. Seven toxin groups matter most in feed; each is matched to its EU value and EU tool in the second table of the next section.

• Aflatoxins (aflatoxin B1 and its milk metabolite M1)
• Zearalenone
• Deoxynivalenol (DON, vomitoxin)
• Fumonisins
• Ochratoxin A
• T-2 and HT-2 toxins
• Ergot alkaloids

Member Table: Mycotoxin Binders, Deactivators and Toxins#

The 14 additive members below cover the additive types sold against mycotoxins in feed, with the EU entry, species and content, expiry and US status side by side; the 9 pages in the second table cover the toxins themselves, the limits and testing. Doses in the first table are EU legal minimum or maximum contents per kg complete feed (12 % moisture where the act says so).

The 1m03i and 1m04 units are measured differently and are not comparable. The second table maps each toxin and control page to the EU value that applies now, its instrument and the EU 1m tool that names the toxin.

How Do Mycotoxin Binders Work?#

Mycotoxin binders work in two ways: adsorbents such as bentonite hold the toxin in the gut so it leaves with the faeces, and deactivators such as fumonisin esterase convert it into a less toxic metabolite. Both routes match the wording of the 1m definition, which covers substances that "suppress or reduce the absorption, promote the excretion of mycotoxins or modify their mode of action".

Adsorption by clays, yeast cell walls and charcoal#

Clays adsorb planar, polar aflatoxin B1 in the smectite interlayer, while yeast cell walls bind less polar toxins such as zearalenone through their beta-glucan and mannan fraction. In bentonite the aflatoxin is chemisorbed between the smectite layers, which lowers its absorption and its carry-over into milk as aflatoxin M1. This binding is non-specific: the same clay surface also binds some drugs, such as macrolides and robenidine, and some micronutrients. Clinoptilolite, a microporous zeolite, has poor affinity for large or non-polar mycotoxins, and it holds only binder and anticaking entries in the EU.

Yeast cell walls of Saccharomyces cerevisiae adsorb zearalenone and other less polar toxins through beta-(1,3/1,6)-D-glucan and mannan, by hydrogen bonding and van der Waals forces. Yeast products are EU feed materials, so a yeast cell wall product has no 1m entry and no legal mycotoxin claim; outside toxin control the same yeast cell walls are sold as a prebiotic source of mannan-oligosaccharides. Activated charcoal, the third adsorbent sold as a binder, has no EU register entry and no US mycotoxin claim.

Conversion of the toxin by enzymes and a bacterial strain#

Deactivators break the toxic part of the molecule: fumonisin esterase cleaves the two tricarballylic acid side chains of fumonisin B1, and the bacterial strain DSM 11798 reduces the 12,13-epoxide of deoxynivalenol to DOM-1. Fumonisin esterase (EC 3.1.1.87) turns fumonisin B1 into hydrolysed fumonisin B1, and EFSA concluded in 2017 that DSM 11798 reduces the 12,13-epoxide of representative trichothecenes. A mycotoxin deactivator therefore acts on a single toxin family, unlike a clay that adsorbs by surface chemistry.

The deactivator identification numbers are 1m01 (DSM 11798) and the fumonisin esterases 1m03i and 1m04 from Komagataella yeasts; the older esterase act for 1m03 (Implementing Regulation (EU) 2017/913) prints an expiry of 2027-06-19. No deactivator exists for zearalenone in the EU: the zearalenone hydrolase ZenA has no register entry, because EFSA (2022) could not conclude on its safety when the production strain carried a kanamycin resistance gene. None of these agents is approved in the US.

Evidence from meta-analyses#

Bentonite lowered aflatoxin M1 transfer into milk from 1.7 % to 0.6 % in the network meta-analysis by Kihal and colleagues (Journal of Dairy Science, 2023), the largest effect of the binders compared. The analysis pooled 28 papers and 131 data points from dairy cows fed aflatoxin B1. HSCAS and clay mixes lowered transfer to 1.04 %, while yeast cell wall reached 1.4 %, a value not significantly different from the 1.7 % control. Reductions of aflatoxin M1 ranged from 25 % for yeast cell wall to 40 % for bentonite.

A second meta-analysis, by Weaver and colleagues (Poultry Science, 2022), covered yeast cell wall extract in broilers under mycotoxin challenge: 25 experiments and 10,307 birds showed 59 g more body weight gain, a feed conversion ratio lower by 0.05 and a mortality change of -1.74 %. The analysis is manufacturer-authored, which a reader weighs against the independent dairy result. Neither meta-analysis covers the EU deactivators; the efficacy findings for those rest on the EFSA opinions behind each 1m entry.

Which Binder for Which Mycotoxin?#

Each 1m entry acts on one toxin group: bentonite 1m558 on aflatoxin B1, fumonisin esterases on fumonisins and DSM 11798 on trichothecenes, while zearalenone and ochratoxin A have no 1m entry. The table below pairs each toxin with its EU 1m entry, the species the entry names and the act behind it.

Selection follows a fixed order: test the feed first, ideally with a multi-toxin LC-MS/MS method, then match the tool to the toxin found, check that the entry names the species, and check interactions with drugs and coccidiostats. Clays fit aflatoxins and little else. Kansas State University extension calls clay binders "vastly ineffective against vomitoxin" and notes that sodium metabisulfite is not FDA-approved for deoxynivalenol; in the EU the only 1m entry that names trichothecenes, including DON, is DSM 11798. Attribute-by-attribute differences between bentonite, yeast cell wall, the enzymes and activated charcoal, with charcoal trial data, sit in mycotoxin binders compared.

Selection by Species and Diet#

Species decides which 1m entry applies, because each entry names its target animals: bentonite names ruminants, poultry and pigs, the enzymes and DSM 11798 name pigs and poultry, and only fumonisin esterase 1m03i in maize-based silage names all species. The table lists the 1m entries per species and the programme page for each.

Toxin binder for poultry#

Three 1m entries name poultry: bentonite 1m558 for aflatoxin B1, DSM 11798 for trichothecenes and fumonisin esterase 1m03i (all poultry species, min 10 U/kg) for fumonisins. DSM 11798 carries a legal minimum content of 1.7 x 10^8 CFU/kg complete feed for poultry and ornamental birds under Implementing Regulation (EU) 2026/549. The older 1m03 act, Implementing Regulation (EU) 2017/913, sets a minimum of 15 U/kg for all avian species with a printed expiry of 2027-06-19.

Bentonite carries the one poultry-specific ceiling in the group. The 1m558 conditions contraindicate coccidiostats other than robenidine above 5 000 mg/kg bentonite in poultry, and they tell users to avoid robenidine itself and simultaneous oral use with macrolides. A broiler diet with a coccidiostat other than robenidine therefore stays at or below 5 000 mg/kg bentonite, a quarter of the 20 000 mg/kg general maximum. No 1m entry names ochratoxin A, although ochratoxins cut broiler intake by 17 % and gain by 20 % in the Andretta meta-analysis.

Toxin binder for pigs#

Pig feed has the widest choice of EU tools: bentonite, DSM 11798, fumonisin esterase 1m03i at 10 U/kg and, for piglets and pigs for fattening, 1m04 at exactly 60 U/kg. The 1m04 entry (Implementing Regulation (EU) 2024/2184) sets 60 U/kg as both minimum and maximum, so it is the only fumonisin esterase with a fixed inclusion. Its units measure hydrolysed fumonisin B1 release at pH 6.0 and 37 °C, while 1m03i units measure tricarballylic acid release at pH 8.0 and 30 °C, so 10 U/kg and 60 U/kg cannot be compared.

Deoxynivalenol cut pig feed intake and gain by 26 % each in the meta-analysis by Andretta and colleagues (2012), and DSM 11798 is the only 1m entry that names it. Zearalenone has no 1m entry, although piglets and gilts carry the lowest EU guidance value for it, 0.1 mg/kg under Recommendation 2006/576/EC.

Toxin binder for cattle and dairy cows#

For cattle compound feed the only 1m entry is bentonite 1m558, for aflatoxin B1 alone; maize silage for cattle can also carry fumonisin esterase 1m03i, an entry that covers all species in maize-based silage. The pressure comes from milk: compound feed for dairy cattle may contain at most 0.005 mg/kg aflatoxin B1 (Directive 2002/32/EC), and raw milk may contain at most 0.050 µg/kg aflatoxin M1 (Regulation (EU) 2023/915).

Bentonite cut aflatoxin M1 transfer from 1.7 % to 0.6 % in the Kihal network meta-analysis. In a single named trial, 60 g bentonite per cow per day decreased milk aflatoxin M1 in Boran and Friesian-Boran cows fed aflatoxin B1 (Kemboi and colleagues, 2023, Journal of Agricultural and Food Chemistry). The same trial fed fumonisin esterase at 120 U per cow per day, a use outside every EU authorisation, since no 1m entry names cattle compound feed for fumonisins.

Horses, maize silage and other species#

No 1m entry for compound feed names horses; the only 1m use open to horses is fumonisin esterase 1m03i in maize-based silage, at a minimum of 40 U/kg fresh material. Equines share the lowest current EU guidance value for fumonisins B1 and B2 with pigs, rabbits and pets: 5 mg/kg under Recommendation 2006/576/EC. From 2027-07-01, Recommendation (EU) 2026/1801 sets 1.0 mg/kg for equines, porcine animals and leporids.

The silage entry (Implementing Regulation (EU) 2021/363) applies to maize-based silages only and runs to 2031-03-21. Compound feed for fish, rabbits, dogs and cats has no 1m entry, and ornamental birds are covered only by DSM 11798.

Dosing Logic: Legal Minimum, Legal Maximum and Trial Doses#

Mycotoxin binder inclusion figures come in three kinds that are never interchangeable: clays carry a legal maximum content (bentonite 20 000 mg/kg complete feed), enzymes and the bacterial strain carry a legal minimum content (fumonisin esterase 1m03i 10 U/kg), and every other figure is a US listing limit, an applicant range or a trial dose. The table gives each figure with its basis and source.

A legal maximum is a ceiling, not a target, and a legal minimum is the lowest content at which the authorisation applies, not a recommended dose. The bentonite applicant range of 500 to 3 000 mg/kg, with 0.5 % considered safe, comes from the EFSA FEEDAP opinion of 2011, and it sits well under the 20 000 mg/kg maximum. EFSA could not conclude in 2017 that bentonite is efficacious for all species, so the 1m558 entry, adopted in 2013, still names only ruminants, poultry and pigs. Clinoptilolite and sepiolite maxima apply to their binder and anticaking functions, so they say nothing about toxin efficacy. Yeast cell wall has no legal or verified dose, and the 120 U per cow per day fumonisin esterase figure is a trial value only.

Regulation Summary: EU Authorisations and US Status#

An EU mycotoxin claim exists only through a 1m authorisation under Regulation (EC) No 1831/2003, while in the US no regulation, approval or GRAS notice grants any product a mycotoxin-binding claim. The EU side carries dated entries and expiries, and the US side carries anticaking and carrier listings with percentage limits.

EU 1m entries, expiry and renewal status#

Six EU acts set the 1m conditions: Implementing Regulations (EU) No 1060/2013 (bentonite), 2017/913, 2018/1568, 2021/363 and 2024/2184 (fumonisin esterases) and 2026/549 (DSM 11798). For bentonite 1m558 the printed expiry is 2023-11-19; the EU Register records a renewal application and still lists the entry pending the Commission decision (Article 14 of Regulation (EC) No 1831/2003). Three EFSA renewal opinions from 2025 and 2026 are positive on safety, but they are opinions, not acts, and no renewal regulation was found as of 3 November 2026. The 1m03 act 2017/913 prints an expiry of 2027-06-19.

DSM 11798 moved to Implementing Regulation (EU) 2026/549, authorised from 2026-04-05 to 2036-04-05, with transitional periods: additive and premixtures labelled before 2026-10-05, feed for food-producing animals labelled before 2027-04-05 and feed for non-food-producing animals labelled before 2028-04-05. EFSA assessed 1m04 in 2026 as safe for all terrestrial species at 360 U/kg, an opinion only, since no extension act exists and 1m04 stays limited to Suidae. How Article 14 renewals work is explained under EU feed additive regulation. In Great Britain, SI 2025/361 revoked the bentonite act (EU) No 1060/2013 and the earlier DSM 11798 acts (EU) No 1016/2013 and 2017/930 from 1 April 2025, and regulation 23 of that instrument carries the authorisations made under them forward with no end date.

US status: no mycotoxin claim for any product#

In the US, clays used as toxin binders are listed only as GRAS substances or food additives for anticaking or carrier use, and none carries a mycotoxin claim. The three US listings that cover binder clays are set out below.

• Bentonite: GRAS under 21 CFR 582.1155 when used in accordance with good manufacturing or feeding practice.
• HSCAS: GRAS under 21 CFR 582.2729 at no more than 2 %.
• Diatomaceous earth: food additive under 21 CFR 573.340 as an inert carrier or anticaking agent at no more than 2 % of the total ration, with lead at most 15 ppm, arsenic at most 20 ppm and fluorine at most 600 ppm.

Deactivators, including fumonisin esterase and DSM 11798, hold no CFR section, animal food GRAS notice or AAFCO definition, and sodium metabisulfite is not FDA-approved as a DON-detoxifying agent.

A binder does not lift a limit: the dilution ban#

A binder never lifts a mycotoxin limit: every 1m additive may only be used in feed that already complies with EU law on undesirable substances, and feed above a maximum content may not be diluted. Article 5 of Directive 2002/32/EC prohibits mixing a non-compliant lot with clean material, so a binder may only be used in feed below the limit. Physical, chemical or microbiological detoxification processes for feed are a separate route, governed by Commission Regulation (EU) 2015/786 and assessed by EFSA.

Binders also face contaminant limits of their own. Directive 2002/32/EC caps binder and anticaking additives at 30 mg/kg lead (60 mg/kg for clinoptilolite of volcanic origin and natrolite-phonolite), 2 mg/kg cadmium, 0.75 ng WHO-PCDD/F-TEQ/kg dioxins, 1.5 ng WHO-TEQ/kg dioxins plus dioxin-like PCBs and 10 µg/kg non-dioxin-like PCBs; these binder ceilings sit with the other undesirable substances in feed.

Sourcing Checklist for Mycotoxin Binders#

Source a mycotoxin binder in seven checks, from the legal claim on the label to the contaminant certificate. The checks below follow the order in which a buyer meets them.

1. Confirm the EU identification number and the target species on the label, for example 1m558 for ruminants, poultry and pigs or 1m01 for pigs, poultry and ornamental birds.
2. Ask for the 1m558 grade data: at least 70 % smectite by X-ray diffraction and aflatoxin B1 binding capacity over 90 % (pH 5.0, 4 mg/L aflatoxin B1, 0.02 % w/v); a 1m558i grade (at least 50 % smectite) is a binder and anticaking clay only.
3. Request a certificate against the binder ceilings of Directive 2002/32/EC for lead, cadmium, dioxins and PCBs.
4. Check the enzyme unit definition and the pelleting stability data, because 1m03i and 1m04 units are not comparable.
5. Check interactions with the coccidiostat programme: the 5 000 mg/kg bentonite ceiling in poultry, and the named coccidiostats with which DSM 11798 may be used.
6. Sample feed before the binder goes in, because bentonite apparently interferes with the analysis of aflatoxin B1 (EFSA 2017); EU official sampling needs an aggregate sample of at least 4 kg and a final sample of at least 500 g.
7. Ask for FAMI-QS or GMP+ certification and the certificate of analysis for each lot.

A buyer should read any "broad-spectrum" claim on a clay or yeast product as a seller's statement, since only the 1m entries carry an EU toxin condition. Bentonite is heat and pellet stable, and enzyme products should come with their own heat-treatment data.

Mycotoxin Binder Questions#

The four questions below cover the legality, interactions, composition and price of mycotoxin binders.

Do binders make contaminated feed legal?#

No: an EU 1m additive may only be added to feed that already meets the maximum contents of Directive 2002/32/EC, and mixing for dilution is prohibited. A binder reduces absorption in the animal; it does not change the measured toxin content of the feed lot. Mould inhibitors do not help either, because they do not remove toxins already formed.

Do mycotoxin binders bind coccidiostats, drugs or nutrients?#

Clays can, because their binding is non-specific: the bentonite act says to avoid simultaneous oral use with macrolides and robenidine in poultry, and contraindicates other coccidiostats above 5 000 mg/kg bentonite. Some micronutrients are bound in the same way. DSM 11798 may be used only with the coccidiostats its act names: narasin/nicarbazin, salinomycin sodium, monensin sodium, robenidine hydrochloride, diclazuril, narasin and nicarbazin.

Handling risks also differ: EFSA renewal opinions of 2025 and 2026 describe bentonite as an eye irritant and a skin and respiratory sensitiser, and EFSA (2025) describes DSM 11798 as a potential skin and respiratory sensitiser. Approved uses, programmes and withdrawal for coccidiostats sit on their own page.

What is toxin binder made of?#

Toxin binders are made of clays (bentonite, HSCAS, clinoptilolite, sepiolite, diatomaceous earth), yeast cell walls, activated charcoal, enzymes or bacteria, often blended. Only three of these materials hold EU 1m entries: bentonite of the 1m558 grade, the fumonisin esterases and DSM 11798. Clinoptilolite and sepiolite hold binder and anticaking entries, yeast cell walls are feed materials, and activated charcoal has no EU register entry.

What drives the price of a toxin binder?#

Toxin binder prices depend on the grade (a 1m558 grade with its aflatoxin B1 condition or a 1g/1i binder clay), the smectite content and binding capacity, the contaminant certificate, enzyme activity and certification, so no single price per kg applies. Offers become comparable on activity per gram for an enzyme product and on grade and test data for a clay. A quote request that names the identification number, the grade and the yearly volume lets suppliers quote on the same basis.