Mycotoxin testing: A primer

Depending on your position within the feed industry, your understanding of how mycotoxin detection works -- and which test best fits your needs -- may vary.

In recent years, mycotoxins seem to be getting more attention than ever. The risks of mycotoxins, a series of toxic chemical byproducts produced by mold in feedstocks, and their impact on animal health are actively combated in the feed and grain industries: feed formulators are increasing their inclusion of additive technology to negate the negative effects of mycotoxins; testing equipment suppliers continue to invest in research and development to improve the process and its results; and feed mills are working to streamline their mycotoxin management programs.

However, depending on your position within the feed industry, your understanding of how mycotoxin detection works -- and which test best fits your needs -- may vary.

“Overall, we’re seeing mycotoxin analysis of finished feed and the various feed ingredients increasing,” explains John Reuther, president, Eurofins Central Analytical Laboratories. “Some years more than others we see a large surge in testing. In those instances, it’s typically the buyer that is concerned, depending on conditions during the crop year, and is looking for more than a standard certificate of analysis for the feed.”

Here, at the onset of the 2014 planting season, the following article serves as a mycotoxin testing refresher, exploring both technology developments and a general overview of when and how feed millers would test their products and ingredients.

What tests are available and why would we use them?

With hundreds of types of mycotoxins on the books, it’s no wonder different testing methodology would be required to best identify which toxins are present and what levels. Here is a list of the most popular test types and their applications:

Lateral flow : Lateral flow tests or lateral flow immunochromatographic assays are simple devices intended to detect the presence or absence of “a target analyte in sample matrix.” In the grain and feed industry, these tests are relatively inexpensive and provide a quick, basic result for the grain being sampled at a grain elevator or feed mill’s receiving station.

“For the feed mill folks, there is still much need for rapid tests because they don't have the time to wait a week for samples to be sent to a lab, analyzed and sent back to them,” says Steve Mobley, 37+ Lab manager, Alltech.

ELISA:  Enzyme-linked immunosorbent assays (ELISA) provides a wet-lab analysis using antibodies to detect a substance in a liquid sample.

“ELISA methods are fast and the accuracy is good. These tests are validated for a number of standard feed ingredients and related byproducts,” Reuther says.

In addition to speed, ELISA tests are popular because they’re easy-to-use and offer a quantitative result; however, it is unlikely that they would be used to analyze finished feed.

HPLC:  High performance liquid chromatography (HPLC) is an analytic technique used to separate, identify and quantify the components of material being tested.

According to Mobley, “Due to increased sensitivity, validated HPLC methods for mycotoxin testing allows the scientist identify more mycotoxins. HPLC is sensitive enough that you can see parts per billion.”

This test requires samples to be sent off to a lab and costs more than a lateral flow test.

“At the low end, you have lower cost, quicker results, but you give up sensitivity and selectivity. So you're going to see fewer mycotoxins and they're going to be there in much higher concentrations to detect them,” Mobley explains. “HPLC is probably the most common commercial laboratory-based test. As you move up in sophistication, you have more sensitivity and more selectivity. You can see maybe a dozen or so mycotoxins at lower concentrations, offering a better picture of the total profile.”

LC-MS-MS:  Liquid chromatography–mass spectrometry (LC-MS-MS) is the most sophisticated type of analytical testing currently available on the marketplace. It is the combination of the separation of liquid chromatography (LC) offered by HPLC, but includes the mass analysis of mass spectrometry. It provides higher levels of selectivity for distinguishing between multiple mycotoxins and higher levels of sensitivity for detecting low levels of the mycotoxins.

“The 37+ lab tested 5,000 samples of a variety of different feed matrices from all regions of the world and we are seeing that consistently we're finding six to eight mycotoxins on average per sample,” says Mobley. “The LC-MS-MS allows us to see more mycotoxins at lower levels. We can detect up to 38 different mycotoxins with our method, and we can detect them at parts-per-billion and parts-per-trillion levels.”

If finished feeds were being tested, either the HPLC or the LC-MS-MS would likely be used. On the ingredient side, LC-MS-MS aids in creating a more accurate dilution of the mycotoxins levels.  

“In a commercial lab, rather than validate an ELISA method for the finished feed, they would choose to use HPLC or LC-MS-MS because the sample will not suffer from the interferences the ELISA method would produce, i.e. generating false positives,” Reuther explains. “LC-MS-MS is a highly controlled, quantitative method that is more rugged and can run for multiple toxins.”

In the end, between choosing HPLC and LC-MS-MS may come down to cost.

“There are some great LC-MS-MS methods out there, but HPLC still does a good job with the major isoforms of the toxin you would be looking for. HPLC is more cost effective; LC-MS-MS costs more because you’re paying for the improved sensitivity,” Kate Plaisance, global analytics director, Cargill Animal Nutrition, which holds select supplier agreements with Charm and one other company.

Aside from cost, the speed at which samples are analyzed is this method’s primary disadvantage.  

Tips running for an effective feed mill mycotoxin management program

Beyond understanding the types of testing available and their best use, there are a number of internal actions that can be set in place to ensure the safety of the finished feed produced in your mill. The following list

ONE: Make sure you know your mycotoxin levels

Once the mycotoxin(s) is bound to the matrix of the material, there’s no way to remove it so the first line of defense is to capture mycotoxin data early and mitigate the risks accordingly.

“It’s important to have a good sampling procedure in additional to protocols when receiving the different grains,” says Jim Topper, Neogen’s market development manager. “Once you’ve accepted the grain the burden falls on you with any issues that arise and there are definite methods for getting a representative sample.”

Plaisance agrees: “There isn’t a good solution for mycotoxin detoxification in a grain, our mycotoxin management strategy is to measure it before it hits the mill. If the supplier tests the grain, we don’t just accept it, we’re going to audit them. If we do that due diligence, then we will accept the proprietor’s certificate of analysis.”

TWO: Mycotoxin test validation

“The No. 1 thing to do when testing for mycotoxins is to make sure that the test you choose is validated to the commodity being tested,” Plaisance says. “In the feed business, we are using a lot of byproducts as well as whole grains.”

For example, a mycotoxin test used for corn should not be used for a corn byproduct.

In choosing a mycotoxin testing vendor, seek out a partner who is transparent in their validation data to ensure the test is appropriate and accurate.

THREE: Detailed information provides balance

As the testing equipment and methodology becomes more sophisticated, feed mills have a better understanding of how many mycotoxins are present and at what levels.

“Testing advancements allow you to see more mycotoxins at lower levels that are present in the sample and have a better understanding of the potential for them to work cumulatively,” Mobley says. “You can have small amounts of half a dozen different types of mycotoxins that work together to affect the health of the animal.”

The ability to know what you’re working with allows for proper grain blending and the additional of mycotoxin binders.

FOUR: Manage your levels beyond the scale

According to Mobley, in-depth, periodic grain analysis gives the feed miller better information for monitoring to ensure “the mycotoxin profile isn’t worsening” as they can develop during transportation and storage.

“Be proactive and anticipate that problems may arise,” Mobley says. “Address those potential problems by periodically testing your grains and product to assure that you are managing the total program: Are you're rotating your stock properly? Are there any variants within the grain where residue could accumulate and create pockets of mycotoxins? Are there areas where moisture might be getting into an area of the storage silo or mill? Identify those areas and change your process.”

He suggests quarterly, seasonal testing of finished feeds.

“If all you’re doing is finished product testing, that is not a quality control program because you’re testing too late. The goal is to keep mycotoxins out so we want to push that testing up the supply chain to have good control,” Plaisance adds.

FIVE: Train your employees

According to Plaisance, 10 percent of the error of accurately describing the mycotoxins levels of a load comes from the actual analytical test used; the other 90 percent of the error is a question of how that truck or railcar was tested.

“The responsibility of the testing is the feed mill’s responsibility and that’s under our control,” Plaisance says.

For this reason testing suppliers, such as Neogen, offers its clients test kit training and certification programs.

How to choose a mycotoxin test

Depending on whether or not you are testing incoming grains or finished feed, your testing needs will vary; however, there are a number of indicators that the vendor or commercial lab will produced the desired results.

“Testing labs need a lot of experience with the various feed types and technologies,” Reuther explains. “Any lab using LC-MS-MS methods there really need to be high-level scientists running the equipment and program quality controls into the run so the data is reliable.”

Lab certification, such as ISO-17205, and participation in mycotoxin check sample programs (AOCS, FAPAS, etc,.) are a good indication you are working with a professional commercial lab.

“The feed mills and the suppliers are in the same business of making sure the animals we feed are healthy, which means we both work to manage mycotoxins to the best of our ability. You need to find a supplier with a good product who is willing to work with you and know your product,” Plaisance advises.

Speed: At grain receiving, operators require a quick response to keep the trucks moving.

Easy-to-use: These technologies do not require sophisticated laboratory setups and can be easily incorporated into the workflow.

Technical support: Rapid tests are only as good as the operator conducting the test. When choosing a mycotoxin test kit provider, make sure the supplier is able to provide training and customer service beyond the sale of the product. 

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