Chemical contaminants cover a broad range of contaminants including but not limited to, natural components of ingredients (e.g., glucosinolates) or natural toxins (e.g., mycotoxins), pesticides, or industrial compounds (e.g., dioxins, melamine, etc.). Under the Animal Feed Contaminants program, chemical contaminants that are routinely monitored include: mycotoxins, pesticides, heavy metals, and dioxin.
On this page:
- Ochratoxin A
Mycotoxins are toxic metabolites produced by certain fungi (molds) that can infect agricultural commodities in the field and/or during storage. The occurrence of these toxins on grains and animal food susceptible to mold infestation is influenced by environmental factors such as temperature, humidity levels, and/or rainfall during growing, harvesting, and post-harvesting seasons. When the undesirable infestation occurs, mycotoxins are produced in food commodities; some of which are used in animal food. The mycotoxins will then remain in the food throughout every phase of food production. Mycotoxins are tough to expel from food and are not destroyed by most of the processes used in animal food production. When consumed by animals or humans, the results can be detrimental causing toxicity or even death. Mycotoxin may cause various toxicological problems such as neurological issues, liver failure, kidney failure, and cardiac failure.
To prevent mycotoxins from becoming an animal health hazard, animal feed manufacturers are required to conduct a hazard analysis that identifies potential hazards within the manufacturing process and provide evidence of consistent monitoring and preventive controls for mycotoxins in animal food.
Aflatoxins are the most commonly researched mycotoxins and are products of the Aspergillus species. Aflatoxins are notorious for the many health consequences that occur from consumption of aflatoxin-contaminated food, including aflatoxicosis and liver damage. Aflatoxins can be produced in crops during the growing season and on food ingredients while in storage. The amount of growth on food ingredients are directly related to the temperature and humidity during production and storage. Thus, the level of aflatoxins contamination in grains fluctuate from season to season.
Aflatoxins are a known carcinogen and their presence in food should be restricted to the lowest practical level. Aflatoxins are also known to cause liver failure in animals. Animals that consume aflatoxin-contaminated food can transfer the toxins to meat, milk and eggs resulting in human exposure to a health hazard.
Deoxynivalenol (DON) is known commonly as vomitoxin. DON is produced by molds in the genus Fusarium, specifically F. graminearum, and is commonly known for its impact on grains such as wheat, barley, oats, and corn.
Its most notorious disease commonly affects wheat and is known as Fusarium Head Blight (FHB). Infections can occur throughout the cultivation process and generally initiate decomposition. If wheat infested with fusarium mold makes its way into the diets of both animals and humans, it may cause symptoms such as vomiting, diarrhea, abdominal pain, headaches, dizziness, fever, and immunological issues. In the animal kingdom, swine are often the most susceptible.
Fumonisins are naturally occurring toxins produced by the molds Fusarium moniliforme (F. verticillioides), F. proliferatum, and other Fusarium species that are common natural contaminants of corn. Fumonisins can cause leukoencephalomalacia in horses and pulmonary edema in pigs and have been linked to a variety of significant adverse health effects in other livestock and experimental animals. Fumonisin B1 is known to induce kidney tumors in male rats and liver tumors in female mice when they consume food containing 50 ppm fumonisin and above. A wide variety of significant adverse animal health effects such as neurological symptoms, cardiopulmonary failures, and kidney failure have been associated with fumonisins. Equine (horses) are extremely susceptible to fumonisins.
Ochratoxin A is a fungus produced regularly by both the genera Aspergillus and Penicillium. The contaminant, ochratoxin A, can be found in cereals and is acknowledged as carcinogen in mice.
Although the FDA has placed limitations on the quantity allowed in animal food, there are still complications because of its heat tolerance. Most fungi would be destroyed when properly cooked, avoiding the adverse effects in animals and humans upon consumption, but Ochratoxin A is resistant to these techniques.
Zearalenone (ZEA) is principally resultant of the fungi F. graminearum contamination of food commodities. Zearalenone is commonly produced in food commodities when there are low temperatures coupled with a high humidity, although the mold can be present in other weather conditions as well. When animals or humans are exposed to zearalenone at low levels, there may not be any visible symptoms as it has a low toxicity. However, when zearalenone is present in food at high levels or when there is consistent exposure at low levels, there have been reports of reproductive disorders and estrogenic effects.
- Guidance for Industry: Action Levels for Poisonous or Deleterious Substances in Human Food and Animal Feed - Aflatoxin Action Levels
- Guidance for Industry and FDA: Advisory Levels for Deoxynivalenol (DON) in Finished Wheat Products for Human Consumption and Grains and Grain By-Products used for Animal Feed
- Guidance for Industry: Fumonisin Levels in Human Foods and Animal Feeds
- Notice: Guidance for Industry: Fumonisin Levels in Human Foods and Animal Feeds; Availability
Federal Register, November 21, 2001, vol. 66, pp 56688-9
- CPG Sec. 670.500 Ammoniated Cottonseed Meal-Interpretation of 21 CFR 573.140
Section 408 of the Federal Food, Drug, and Cosmetic Act (FFDCA) authorizes the U.S. Environmental Protection Agency (EPA) to set tolerances, or maximum residue limits, for pesticide residues on foods. Under FFDCA, FDA has the responsibility to enforce EPA-established pesticide tolerances in foods imported into the U.S. and domestic foods shipped in interstate commerce (with the exception of meat, poultry, and certain egg products regulated by the Food Safety Inspection Service (FSIS) of the U.S. Department of Agriculture). To accomplish this task, both the Center for Food Safety and Applied Nutrition (CFSAN) and CVM manage a Pesticide Residue Monitoring Program. Each year, FDA investigators collect a variety of animal food samples as part of CVM’s Feed Contaminants Compliance Program and send them to the Office of Regulatory Affair’s (ORA) laboratories for pesticide analysis. This program allows FDA to gather information on pesticide residues in animal foods and food ingredients; thereby protecting both human and animal health.
- CPG 575.100 Pesticide Residues in Food and Feed - Enforcement Criteria
- 40 CFR 180-Tolerances and Exemptions for Pesticide Chemical Residues in Food
- CFSAN Annual Pesticide Reports
- Summary of Pesticide Residues in Domestic Surveillance and Import Samples of Animal Food and Animal Food Ingredients during Fiscal Year 2015 (FY15)
- Summary of Feed-Through Pesticide Residues in Domestic Surveillance and Import Samples of Animal Food and Animal Food Ingredients During Fiscal Year 2000 Through 2018
- CFSAN pesticide program
- EPA Pesticide Ingredients
- Pesticide Analytical Manual Volume I
- Pesticide Analytical Manual Volume II Index
- Glyphosate Questions and Answers (CFSAN)
Dioxins and polychlorinated biphenyls (PCBs) are groups of compounds. Some of the dioxin and PCB congeners may be carcinogens at low levels of exposure over extended periods of time.
- There are no tolerances or other administrative levels established by the FDA for dioxins in animal food.
- Temporary tolerances for PCBs in animal food can be found in 21 CFR 509.30.
FDA, in conjunction with the European Union and the U.S. EPA and USDA, is addressing both international and domestic dioxin and PCB concerns in animal food. One example of each is provided below.
Domestic Dioxin Concern
In July 1997, FDA found contamination of animal food with dioxin, which resulted in elevated levels of dioxin in chickens, eggs and catfish. Dioxin contamination was found in animal food distributed to over 3,400 consignees throughout the country.
- The source of the dioxin contamination was traced to a mined clay product called "ball clay," which is used as an anti-caking agent in soybean meal, in other feed components, and in complete animal food.
- CVM worked cooperatively with the affected industries to halt any further distribution and use of the animal food known to be contaminated with dioxin. This was carried out across the country.
- In 1999, ball clay was not accepted for use as an ingredient by the Association of American Feed Control Officials, Inc.
- In FY 1998, FDA initiated steps to determine whether other mined clay products and naturally derived anticaking agents were contaminated with dioxin.
- Industry associations met with CVM to determine the type of information needed, which resulted in a compilation of industry sampling of anticaking agents for dioxins.
FDA, with analytical assistance from EPA, surveyed mined animal food ingredients for the presence of dioxins, as a supplement to industry sampling.
International PCB Concern
FDA received information that fat from a rendering company in Belgium was contaminated with PCBs and dioxin in January of 1999. This product was shipped to animal food manufacturers and incorporated into animal food distributed to poultry, hog and cattle farms in Belgium, France, and the Netherlands, with the majority of the product going to Belgium. Analysis of chickens and eggs in Belgium revealed elevated PCBs levels and low levels of dioxins.
- On June 4,1999 FDA issued an Import Bulletin to the field directing animal food, and animal by-products for animal food from France, Belgium and Netherlands, and egg-containing products, from Belgium offered for entry into the U.S. to be held at the port of entry.
- On June 11, 1999 FDA issued Import Alert 99-24, "Detention Without Physical Examination of Human Food Products and Animal Feeds Contaminated with Dioxin and/or PCB Compounds".
On August 23, 1999, FDA issued a guidance representing the Agency's current thinking on possible dioxin/PCB contamination of animal source material in EU countries: Guidance for Industry: Possible Dioxin/PCB Contamination of Drug and Biological Products.
Melamine has been approved by the FDA for use in packaging, adhesives, filters, and use in other food contact surfaces. Thus, there may be low levels of melamine in domestic food as a result of these approved uses in the US. In other countries, melamine is a frequent component of fertilizers. When feed/food become contaminated with both melamine and cyanuric acid, it can be hazardous to both animals and humans via the formation of crystals that block the kidney.
- FY 2008 Nationwide Survey of Distillers Grains for Antibiotic Residues (PDF - 62KB)
- Report of FY 2008 Nationwide Survey of Distillers Products for Antibiotic Residues
- FY 2010 Nationwide Survey of Distillers Grains for Antibiotic Residues
- Report of FY 2010 Nationwide Survey of Distillers Products for Antibiotic Residues
- LIB NO 4423 GC/MS method for melamine and analogues
- LIB NO 4438 Detection of Antibiotic Residues in Distillers Grains (PDF - 228KB)
- Dioxin congener patterns in commercial catfish from the United States and the indication of mineral clays as the potential source
Heavy metals are inherent to the environment and can be both helpful and harmful, nonetheless, they are frequently present in animal food. The difficulty to eliminate these metals from diets is irrefutable as they are naturally absorbed by florae used in animal food production. Under the Feed Contaminant program, the FDA routinely tests animal food, including pet food, for heavy metals.
There are two types of metals that are regulated.
- The first are imperative to the animals’ health. They might help with growth, weight, or be required by the body in its rebuttal of diseases. If the animal is not provided with enough of this type of metal, there may be weight loss or other symptoms that could be fatal.
- The second are non-essential and these consist of metals that neither help nor harm the organisms. These also might be metals that could be tolerated by the animal, but lethal to humans when passed on through their byproducts.