Molds and Mycotoxins - Sampling Feed to Test for Mycotoxins

When to test for mycotoxins:

• When moldy feeds are being fed and/or moldy feeds make up a significant proportion of the ration.

• When substantial changes in production and health are observed in a large proportion of the animals on feed.

• Decline in performance and health that cannot otherwise be readily explained and symptoms typical of the effects of mycotoxins are present.

What to sample for mycotoxins tests:

• Sample individual suspect ingredients.

• Sample concentrate rations.

• Sample the total mixed ration or grain and forages separately when fed conventionally.

Problems with sampling for mycotoxin analysis

• Mycotoxins are often present in very small amounts (ppm and ppb).

• Mycotoxin content is not related to the amount of mold present.

• Mycotoxins are not necessarily evenly distributed in the affected feed. Isolated pockets may exist.

• Some mycotoxins could develop during lengthy transit to the laboratory.

• Some mycotoxins continue to be produced in storage, particularly unfavourable storage.

Wet and dry feeds need to be sampled and handled differently

• Dry feeds are any feeds with 12% moisture or less. For example dry grains, protein supplements, dry hay and concentrates.

• Wet feeds are any feeds with 15% moisture or greater. For example TMR, corn silage, haylage and high moisture grains.

• Feeds between 12 and 15% moisture; grey area. Judgement call as how best to handle. If in doubt, it is safer to handle as a wet feed.

Sampling method #1 for dry feeds (Penn State University)

• Take 8 - 12 samples at each of 3 - 5 feedings or feed removal from storage.

• Mix the subsamples well, take a 500g composite sample and store in a cool dry place.

• Combine at least 3 - 5 composites, mix well and take 500g sample for submission to the laboratory.

• Store all samples in clean double layer paper (grocery store) or cotton bags.

• Keep an additional 500g sample for confirmation or other analyses.

Sampling method #2 for dry feeds (Penn State University)

• Take 12 - 20 stream samples from an entire delivery, or 12 - 20 deep probe samples from a bin. Include samples from the sides of bins or edges of storage where mold is likely to occur.

• Mix samples as above and take a final 500g composite sample for submission to the laboratory.

• Place sample in a clean double layer paper or cotton bag (available at the grocery stores) and keep in a cool dry place. Don't use plastic bags with dry samples.

Agri-Food Laboratory in Guelph

• Sampling must be random but at the same time be aware that molds tend to be at the sides of bins so some samples must be included from these parts of the bin.

• Agri-Food Lab recommends taking a composite sample of 1 kg (1,000g) for submission to the laboratory for mycotoxin analysis.

Always collect a number of samples (up to 20 lbs or 10 kg total), mix and subsample, store in clean paper or cotton bags, keep in cool dry place and get to the lab as soon as possible. The shorter the delay between sampling and analysis, the more reliable the results are likely to be.

Sampling method for wet feeds (Penn State University)

• Take 8 - 12 sub-samples of wet feeds at each of 3 - 5 feedings or feed removal from storage.

• Mix the sub-samples well and take a 750 - 1000g composite sample.

• Place the composite sample in a thick or double plastic bag. Pack the sample tightly, forcing out as much air as possible and seal well.

• Store samples in the freezer till the final composite is prepared.

• Combine the 3 - 5 composite samples and mix them well. Take a final 1kg composite sample to submit to the laboratory for mycotoxin analysis.

• Take a second 1kg sample to submit to a laboratory for moisture analysis.

• Take a third 1 kg sample and store in the freezer for confirmatory or other analyses as required.

• Always store wet samples in the freezer till they are submitted for analysis.

• Always ship wet samples frozen, use an insulated bag with ice packs. If possible hand deliver samples to the laboratory as soon as possible after the final composite sample is prepared and frozen.

   

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