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Food safety: Monitoring feed sources to prevent residues

Tianna Fife and Jackie Owens Published on 01 August 2011
Zilmax equipment

A part of our responsibility as food producers is ensuring the safety and wholesomeness of our product – beef.

Today’s consumers are interested in how their food is produced.

This includes everything from how animals are handled and what they are fed to what they are given to prevent and treat diseases, and everything in between.

Antibiotics and implants have received attention from consumers, some of whom have criticized production practices and management due to their worries about drug and chemical residues.

Therefore, as producers, we need to take a step back and determine the best way to educate consumers about our production practices, why they are important and the science behind them.

What is a residue?

Residues are remnants of compounds in drugs and other substances found in fluids, tissues and feeds.

There are specific tolerance levels for different substances, which are traces of the chemicals and drugs that may be allowed in certain tissues.

The Food Safety and Inspection Service (FSIS) enforces the tolerance and action levels set by the Environmental Protection Agency (EPA) and the Food and Drug Administration (FDA) to ensure meat products do not violate these levels.

Any violation of these legal limits can result in fines, herd quarantine and possible criminal prosecution.

What steps are taken to ensure beef products do not contain violative residues?

There are strict protocols enforced at the time of harvest to monitor for residues. Traditionally, specific animals were tested based on pre-harvest conditions including disability, injury, evidence of a recent surgery or signs of illness.

In those situations, it was likely the animals were treated with some type of product and there was an increased risk of violative residues.

Today, there is also additional testing conducted and animals are randomly selected post-harvest for residue testing. If the marker residue exceeds the tolerance level, then the entire carcass is condemned.

It is important to remember that all of this testing is in addition to those conducted to detect foodborne pathogens, as well as quality assurance monitoring.

Food producers and various government agencies in the U.S. put great emphasis on the safety of the food supply.

Therefore, extensive research is performed and best management practices are implemented by producers and others throughout the beef production chain.

Production practices to consider in preventing violative residues

For most of us, when we think of drug residues, we immediately think of injectable health products. Wrongful administration, not following withdrawal times or extra-label drug use, can all lead to violative residues from an injectable health product. However, our feed sources can also be an element of risk; therefore, the remainder of this article will focus on feed sources.

What are some reasons drug residues may occur from feed sources?

Reasons include: not adhering to appropriate withdrawal times or label directions, miscommunication, inadequate or inconsistent record keeping, pesticide/chemical contaminations or possibly feeding an unapproved combination of medicated supplements.

By following the Beef Quality Assurance (BQA) guidelines listed below, we can reduce the risk of drug residues and ensure the quality of feed sources:

  • Maintain records of pesticides and other chemicals used on pastures or crops
  • Have an adequate quality control program for incoming feedstuffs and analyze suspect feedstuffs
  • Do not feed ruminant-derived protein sources
  • Feed only byproducts whose use is supported by sound science
  • Use only FDA-approved medicated feed supplements and follow all label directions
  • Do not use medicated feed supplements extra-label
  • Adhere to withdrawal times
  • Keep complete records when mixing and feeding medicated supplements
  • Follow proper cleanout procedures for all equipment used to mix medicated feeds

Records of pesticide/chemical applications

It is imperative appropriate records are kept for pesticides applied to fields and pastures intended for feed production use.

Producers need to follow the laws and regulations for applying specific products and maintaining records of product use.

These records, along with any other information that will be beneficial in reducing the risk of violative residues, should be maintained.

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All animal health, feed and application records should be kept for a minimum of three years, as recommended by BQA guidelines.

Quality control program

A quality control program should be in place for all feeds – purchased and home-raised. Collecting samples and conducting a nutrient analysis on all feedstuffs enables the producer to match feed ingredients to the correct class of animals in the most economical way.

Inspect feeds for color, odor, moisture, temperature and evidence of foreign material or other types of contamination from birds, rodents or insects.

A sample of all feedstuffs should be taken and stored (note: high-moisture samples should be frozen and dry samples should be kept in a dry area) in case there is ever a question of feed quality or contamination.

It is recommended that a supplier’s assurance of quality is obtained. Suspect feeds should be analyzed before they are fed.

Some feeds are higher risk for spoilage, as well as nutritional variation. Some examples of those would be fats, oils, high-moisture feeds and byproducts, which should have an analysis and be fed based on sound science.

Molds and mycotoxins can also be problems in grains and forages. When buying and feeding various feed ingredients, it is important to consider the possibility of contamination at any stage: growing, harvesting, handling, transporting, storing or during any other time feed may be altered.

Feeding medicated supplements, following the label and keeping records

As an industry, it is essential all beef producers use only FDA-approved medicated feed supplements and follow all labels accordingly.

An area of concern is combination feeding, which is sometimes referred to as “AM/PM” feeding. This is when one medicated supplement is fed in the morning and another fed in the afternoon.

Combination feeding of medicated supplements must be FDA-approved; otherwise, it violates federal regulations and thus is illegal.

Even the feeding of a medicated pellet on top of a medicated ration is considered combination feeding and is not allowed unless the combination is FDA-approved.

For approved feed supplement combinations, producers can contact their veterinarian, pharmaceutical supplier or go online: Food Animal Residue Avoidance and Depletion Program – or FDA Green Book – Examples of current FDA-approved combinations are:

  • Bovatec (lasalocid) + Aureomycin (chlortetracycline)
  • Deccox (decoquinate) + Aureomycin (chlortetracycline)
  • Rumensin (monensin) + Tylan (tylosin) + Deccox (decoquinate)
  • Rumensin (monensin) + Tylan (tylosin) + MGA (melengestrol acetate)

How can producers prevent drug residues from occurring due to medicated feed supplements?

Follow all label directions, do not use products extra-label and keep appropriate records for a minimum of three years. The following is an example of what information BQA guidelines recommend to keep:

  • Medicated feed supplement used
  • Date used
  • Ration name and number
  • Animals/pen receiving medicated feed supplement
  • Name of person adding/mixing feed that includes a medicated supplement
  • Amount of medicated supplement fed
  • Withdrawal time


It is vital that we follow all label directions and utilize our records to avoid drug residues. Beyond this, it is also crucial that we, as the beef industry, tell our story and educate consumers.

We are producing a safe and wholesome product that is of the highest quality. Let consumers know we are monitoring ourselves as an industry and implementing practices that are humane, economical, safe, environmentally friendly and science-based.  end_mark

Tianna Fife is a county extension educator for the University of Idaho.
Jackie Owens is the Idaho Beef Quality assurance program coordinator.


TOP: Medicated feeds must follow federal guidelines, and producers should closely monitor combination feedings to make sure they are allowable. Photo by David Cooper.

BOTTOM: A quality control program for your feed means conducting nutrient analysis and inspecting feeds for color, odor, moisture, temperature and any foreign material or contamination. Photo by Philip Warren.

tianna fife

Tianna Fife
University of Idaho
Idaho Beef Quality

jackie owens

Jackie Owens
University of Idaho
Idaho Beef Quality