In this chapter: why a mistake in a feed mill can end up on people's tables, what the regulations of the European Union, the United States, the Codex and Argentina require, what the four main hazards are (cross-contamination, mycotoxins, Salmonella and pests), and how to organize cleaning, traceability and records. At the end, a short section for wood pellet plants.
Animal feed is food, too
A feed mill does not sell a final product. It sells the first link in a chain that ends in the milk, eggs and meat any family buys. If the feed is contaminated, the animal eats it, the contaminant passes into its tissues or into what it produces, and the problem keeps moving down the chain.
The cases that prove it are well known:
- Belgium, 1999. In mid-January, a tank of animal fat was contaminated with PCBs and dioxins, probably through mineral oil. That fat was sold to feed mills in Belgium, France and the Netherlands, and it ended up in about 500 tonnes of feed. The authorities only learned of the problem at the end of April, when the animals had already eaten that feed. The highest levels appeared in chicken fat and in eggs1. After the crisis, the European Commission set new maximum limits for dioxins.
- Salmonella Agona, 1972. The first Salmonella Agona outbreak recorded in the United States was traced back to animal feed made with contaminated imported fish meal2.
- Aflatoxins in milk. When a dairy cow eats feed containing aflatoxin B1, part of it is transformed and comes out in the milk as aflatoxin M1. The European Food Safety Authority (EFSA) estimated that transfer at 1 to 2%, and it can reach 6% in high-yielding cows3. That is why the limits for dairy cow feed are the strictest.
What the regulations require
European Union
- Regulation (EC) 183/2005, on feed hygiene. Article 6 requires manufacturers to put in place and maintain a permanent written procedure based on HACCP principles (Hazard Analysis and Critical Control Points)4. Article 5(6) requires sourcing only from registered or approved establishments. Its Annex II requires facilities, equipment, containers and vehicles to be kept clean, with effective pest control programs, and measures to prevent cross-contamination between batches5.
- Regulation (EC) 178/2002, general food law. Article 18 establishes traceability at all stages. Every feed business operator must be able to identify who supplied each raw material and which businesses received its product, and provide that information to the authority on request6.
- Directive 2002/32/EC, on undesirable substances in animal feed, sets mandatory maximum levels, including the one for aflatoxin B1. Recommendation 2006/576/EC gives guidance values for other mycotoxins7. From July 1, 2027, it is replaced by Recommendation (EU) 2026/1801, which lowers several of those values. We cover them below.
United States
- 21 CFR Part 507. This is the FDA rule under the Food Safety Modernization Act (FSMA), published as a final rule on September 17, 2015. It requires good manufacturing practices and preventive controls for animal food. The manufacturer must have a written food safety plan (§507.31) based on a hazard analysis (§507.33)8.
- 21 CFR Part 225. These are the good manufacturing practices for medicated feeds. Section 225.65 requires adequate cleanout procedures for all equipment to prevent contamination of feed with drugs9.
- Compliance Policy Guide CPG 690.800 (2013). It guides FDA staff on the presence of Salmonella in all animal food, including pet food10.
Codex Alimentarius
The Code of Practice on Good Animal Feeding (CXC 54-2004) aims to ensure the safety of food for human consumption through good animal feeding practices on the farm and good feed manufacturing practices, along the whole chain11. Where there is no detailed national regulation, it is the international reference.
Argentina
Resolución SENASA 1416/2024 sets the standard for establishments that handle products for animal feed. Those who manufacture, repackage or store these products must be authorized and have a technical director. For those who manufacture or repackage, Good Manufacturing Practices (GMP) are mandatory, with a period of twelve months from authorization to implement them. Warehouses must apply sanitation standard operating procedures (SSOP) and integrated pest management. SENASA can also require a HACCP system when the establishment's risk justifies it12. This resolution replaced Resolución 594/2015, which had already made GMP mandatory13.
In other countries, check with the local health or agricultural authority (Chapter 2).
The four main hazards
1. Cross-contamination
A feed mill usually makes many formulas on the same line: for broilers, for pigs, for dairy cows, with and without drugs. Whatever remains inside the mixer, a conveyor or a hopper passes into the next batch. This is called carryover.
The most sensitive case is veterinary drugs. A drug residue in the feed of laying hens or dairy cows can leave residues in eggs or milk. Regulation (EU) 2019/4, on medicated feed, requires measures against cross-contamination, written cleaning plans and separate storage, with stricter levels for animals that produce milk or eggs and those close to slaughter14.
The regulations recognize three tools, which are usually combined9:
- Physical cleanout: vacuuming, sweeping or washing the equipment.
- Flushing: running a quantity of drug-free material through the line to clean it. That material is identified, stored separately and used in a way that does not contaminate other feed.
- Sequencing: ordering production so that, if there is any carryover, it goes into a feed where it does no harm.
Line design also matters: the less material that stays inside mixers, conveyors and hoppers, the less carryover there is.
2. Mycotoxins
Mycotoxins are toxic substances produced by some molds on grain, in the field or in storage: aflatoxins, deoxynivalenol (DON), zearalenone, ochratoxin A, T-2 and HT-2 toxins, and fumonisins. Do not count on the process to remove them: control happens beforehand.
Some European Union reference values, all based on a feed with 12% moisture7:
| Mycotoxin | Product | Value (mg/kg) | Type |
|---|---|---|---|
| Aflatoxin B1 | Feed materials | 0.02 | Mandatory maximum |
| Aflatoxin B1 | Complete and complementary feed (general) | 0.01 | Mandatory maximum |
| Aflatoxin B1 | Compound feed for dairy cattle, sheep and goats, calves, piglets and young poultry | 0.005 | Mandatory maximum |
| Deoxynivalenol | Feed for pigs | 0.9 | Guidance |
| Ochratoxin A | Feed for pigs | 0.05 | Guidance |
| Ochratoxin A | Feed for poultry | 0.1 | Guidance |
The guidance values in the table are those of Recommendation 2006/576/EC, which applies until June 30, 2027. Recommendation (EU) 2026/1801 applies from July 1, 2027, and from October 1, 2027, for corn, sorghum, soybeans, sunflower and their products. The new recommendation lowers several of these values. If you export to the European Union or make feed with raw materials headed there, it makes sense to work with the new values now.
In the United States, the FDA uses action levels, not fixed legal limits. For aflatoxins, the general level is 20 parts per billion (ppb), which includes feed for dairy animals; the highest, 300 ppb, is for corn and peanuts intended for finishing beef cattle in feedlots15.
The defense against mycotoxins starts at receiving: known suppliers, sampling of every lot, testing when the risk justifies it, and rejection of goods that do not comply. It continues in storage: dry grain, clean silos, no water leaks and no condensation.
3. Salmonella
In 2008, the EFSA Panel on Biological Hazards concluded that Salmonella is the main biological hazard in animal feed, and that contaminated feed can be a source of infection for animals and for the products obtained from them16. It identified oilseed meals and animal-derived proteins as the main routes of entry into compound feed.
Heat treatment is the most effective decontamination method, and conditioning and pelleting heat the feed. But the same report warns that feed can become contaminated again afterward, during cooling and handling16. That is why the cooler, finished product conveyors, load-out silos and trucks need the strictest hygiene.
The usual measures are to separate raw material areas from finished product areas, control condensation inside coolers and silos, clean at a defined frequency, and take environmental and product samples according to a plan.
4. Pests
Rodents, birds and insects find food and shelter in a feed mill. They soil the product, can transmit pathogens, and damage bags and cables. Regulation 183/2005 requires effective pest control programs, and Resolución 1416/2024 requires integrated pest management in warehouses512.
A serious program includes a map with numbered bait stations and traps, inspection at a fixed frequency, a record of findings, sealing of openings, and cleanup of spills. Baits never go where they could fall into the product.
Cleaning: a program, not a habit
Cleaning works both against combustible dust (Chapter 3) and for product hygiene. Both are handled with a written program that states, for each piece of equipment and area, what is cleaned, how often (per shift, per day, at each formula change), how, who does it, who checks it and where it is recorded.
The areas that tend to be forgotten are the inside of the mixer, the bucket elevator boots, hoppers, the cooler, cyclones and finished product silos. Before going in to clean a hopper or a silo, you must apply energy lockout (Chapter 4) and, where applicable, the confined space entry permit (Chapter 7).
Lot traceability and records
If a problem arises, the question will always be the same: where did it come from and where did it go? To answer it in hours rather than weeks, every product lot must be traceable to:
- the lots of raw materials, additives and premixes used, with their supplier and date received;
- the date, shift and line on which it was made;
- the formula and the production sequence for that day;
- the customers and trucks that received it.
The minimum records are: receiving of goods (with tests and rejections), production by lot, cleanouts and formula changes, pest control, maintenance, complaints, and product recalls. The official UK guidance on Regulation 183/2005 recommends keeping them until the products are likely to have been consumed, which in some cases means several years17.
In Chapter 12, we look at how to organize all of the plant's records.
Wood pellet plants: workplace and product hygiene
Wood pellets are not food, but they have their own hygiene too.
The workplace. Fine wood dust is combustible (Chapter 3) and affects the respiratory tract. Housekeeping is the first measure; respiratory protection is covered in Chapter 10.
The product. Pellet quality starts with the raw material. The international standard ISO 17225-2:2021, on graded wood pellets, only covers pellets made from virgin wood, by-products and residues from the wood-processing industry, and chemically untreated used wood18. Painted, varnished, glued or preservative-treated wood can contribute heavy metals and other compounds that do not belong in a clean fuel. That is why raw material receiving must check its origin and reject what does not belong.
The other common contaminant is metal: nails, staples, wire and loose parts. They damage the die and rollers, can cause sparks in the mill (Chapter 3), and end up in the product. Magnetic separators ahead of the mill and the pellet mill, with periodic, recorded cleaning, are the basic measure.
Chapter checklist
- Do we have a written food safety plan based on a hazard analysis (HACCP or whatever our regulations require)?
- Do we buy only from registered or approved suppliers, and can we prove it?
- Is every incoming lot sampled and recorded, with written rejection criteria?
- Do we have a procedure against cross-contamination (cleanout, flushing, sequencing), and is every formula change recorded?
- Is flush material identified and stored separately?
- Do we test for mycotoxins in the highest-risk raw materials and according to the feed's intended use?
- Is the finished product area separated from the raw material area, and is condensation controlled in coolers and silos?
- Is there a pest control program with a map, frequency and records?
- Is there a written cleaning program with frequency, method, person responsible and record?
- Can we trace a lot backward (raw materials) and forward (customers) within a few hours?
- In wood pellet plants: do we check the origin of the wood, and do we clean the magnetic separators and record it?
What to leave to a professional
The hazard analysis and the food safety plan must be prepared by people trained in HACCP, with the actual data from your plant, your raw materials and your customers. Validating cleanout against drug carryover, the sampling plan for mycotoxins and Salmonella, and approval by the health authority also require a professional, and in Argentina, the technical director that SENASA requires.
At Meelko, we design feed mill lines with hygiene in mind as well: equipment that empties well, access for cleaning and inspection, and separation between the raw material area and the finished product area. If you are planning a plant or want to review yours, tell us about your project.
Chapter sources
- Van Larebeke, N. et al. The Belgian PCB and dioxin incident of January-June 1999: exposure data and potential impact on health. Environmental Health Perspectives, 2001, 109(3): 265-273. https://webarchive.library.unt.edu/eot2008/20090118181958/http://www.ehponline.org/members/2001/109p265-273vanlarebeke/vanlarebeke.pdf ↑
- CDC. Multistate Outbreak of Salmonella Serotype Agona Infections Linked to Toasted Oats Cereal — United States, April-May, 1998. MMWR, 1998 (background). https://www.cdc.gov/mmwr/preview/mmwrhtml/00053368.htm — Original paper cited there: Clark, G. M., Kaufmann, A. F., Gangarosa, E. J. and Thompson, M. A. Epidemiology of an international outbreak of Salmonella agona. The Lancet, 1973;2(7827):490-493. doi: 10.1016/s0140-6736(73)92082-5. PubMed: https://pubmed.ncbi.nlm.nih.gov/4125005/ ↑
- Zentai, A., Jóźwiak, Á., Süth, M. and Farkas, Z. Carry-Over of Aflatoxin B1 from Feed to Cow Milk — A Review. Toxins, 2023, 15(3): 195. https://pmc.ncbi.nlm.nih.gov/articles/PMC10053009/ ↑
- Regulation (EC) No 183/2005 of the European Parliament and of the Council of January 12, 2005, laying down requirements for feed hygiene, Articles 5(6) and 6. https://eur-lex.europa.eu/legal-content/ES/ALL/?uri=CELEX:32005R0183 ↑
- Regulation (EC) No 183/2005, Annex II (facilities and equipment; production). Text: https://legislation.gov.uk/eur/2005/183/annex/II/division/2?view=plain — Food Standards Agency guidance on cross-contamination between batches: https://www.food.gov.uk/sites/default/files/media/document/on-farm-mixinf-guidance-farmers.pdf ↑
- Regulation (EC) No 178/2002, Article 18 (traceability). https://eur-lex.europa.eu/eli/reg/2002/178/2019-07-26 — Text of the article: https://www.legislation.gov.uk/eur/2002/178/article/18 ↑
- Directive 2002/32/EC on undesirable substances in animal feed, Annex I, replaced by Regulation (EU) No 574/2011. https://eur-lex.europa.eu/eli/dir/2002/32/2019-11-28/eng — Commission Recommendation 2006/576/EC of August 17, 2006, on the presence of deoxynivalenol, zearalenone, ochratoxin A, T-2 and HT-2 and fumonisins in products intended for animal feeding (consolidated version 2016). https://eur-lex.europa.eu/eli/reco/2006/576/2016-08-02 — Commission Recommendation (EU) 2026/1801 of July 24, 2026 (OJ L, July 28, 2026), replacing Recommendations 2006/576/EC and 2013/165/EU from July 1, 2027. https://eur-lex.europa.eu/eli/reco/2026/1801/oj — Summary: https://www.csqa.it/en-us/press/micotossine-nei-mangimi-la-ue-aggiorna-i-valori-di-riferimento ↑
- FDA. 21 CFR Part 507, Current Good Manufacturing Practice, Hazard Analysis, and Risk-Based Preventive Controls for Food for Animals, final rule of September 17, 2015, §507.31 and §507.33. https://www.ecfr.gov/current/title-21/chapter-I/subchapter-E/part-507 ↑
- FDA. 21 CFR 225.65, Equipment cleanout procedures. https://www.law.cornell.edu/cfr/text/21/225.65 ↑
- FDA. CPG Sec. 690.800 Salmonella in Food for Animals, July 2013. https://www.fda.gov/regulatory-information/search-fda-guidance-documents/cpg-sec-690800-compliance-policy-guide-salmonella-food-animals ↑
- Codex Alimentarius. Code of Practice on Good Animal Feeding (CXC 54-2004). https://www.fao.org/fileadmin/user_upload/livestockgov/documents/CXP_054e-1.pdf — FAO platform: https://www.fao.org/feed-safety/resources/resources-details/es/c/1054052/ ↑
- SENASA. Resolución 1416/2024, Norma de Establecimientos y de Directores Técnicos de Establecimientos de Productos destinados a la Alimentación Animal, Boletín Oficial, December 4, 2024. Text: https://www.cira.org.ar/?p=21330 — Boletín Oficial: https://www.boletinoficial.gob.ar/detalleAviso/primera/317685/20241204 ↑
- SENASA. Resolución 594/2015. https://www.produccion-animal.com.ar/legales/54-Resolucion_594.pdf — On its replacement by Resoluciones 1415 and 1416/2024: https://www.engormix.com/balanceados/miscellaneous/argentina-nuevo-sistema-aprobar_n30874/ ↑
- Regulation (EU) 2019/4 on the manufacture, placing on the market and use of medicated feed, and its Annex I (written cleaning plans and separate storage). https://www.legislation.gov.uk/eur/2019/4/annexes — Official text on EUR-Lex: https://eur-lex.europa.eu/eli/reg/2019/4/oj ↑
- FDA. CPG Sec. 683.100 Action Levels for Aflatoxins in Animal Food. https://www.fda.gov/regulatory-information/search-fda-guidance-documents/cpg-sec-683100-action-levels-aflatoxins-animal-feeds ↑
- EFSA, Panel on Biological Hazards (BIOHAZ). Microbiological risk assessment in feedingstuffs for food-producing animals. EFSA Journal, 2008, 6(7): 720. Summary: https://www.thepoultrysite.com/news/2008/07/efsa-publishes-advice-biological-feed-hazards ↑
- Food Standards Agency (United Kingdom). Farmers producing animal feed. https://www.food.gov.uk/business-guidance/farmers-producing-animal-feed ↑
- ISO 17225-2:2021, Solid biofuels — Fuel specifications and classes — Part 2: Graded wood pellets. Scope: https://standards.iteh.ai/catalog/standards/iso/268f4ee0-a1ca-40af-b57d-60790cee914d/iso-17225-2-2021 ↑
