ISSUE FOCUS FEED & ADDITIVE MAGAZINE March 2024 55 Good to know: The chances of identifying mycotoxins in feed increase if the samples are taken from feeders inside the farm. This is because the feed has been stored inside the farm silos for about 5 to 7 days, and for about a day in the feeders inside the rearing facility. The longer feed is exposed to the environmental conditions (high moisture and temperature) present in a farm, the greater the chance of identifying mycotoxins. 3. Laboratory Techniques The choice of laboratory technique impacts results. High Precision Liquid Chromatography (HPLC) is more sensitive than Enzyme-Linked Immunoassay (Elisa), so lower mycotoxin levels can be detected. Advanced techniques – like Liquid Chromatography coupled with Tandem Mass Spectrometry (LC/MS/ MS) – offer specificity and speed, while analysing numerous metabolites and mycotoxins simultaneously. 4. Conjugated or Masked Mycotoxins The presence of these derivatives, formed during plant growth, poses a new challenge. Conventional tests may not detect them due to chemical changes in mycotoxin structures. Enzymes produced by plants during growth contribute to these variations. The mycotoxins adhere to other nutrients, such as sugars (glucose), fatty acids or amino acids. WHERE AND HOW TO TAKE SAMPLES To determine which ingredients are contaminated, or when mycotoxin levels increase during feed preparation in a feed mill, it is necessary to take samples in the following areas: 1. Trucks or railroad cars To take samples from trucks or railroad cars that transport the grains to the feed mill: • Use a bulkhead gauge or probe with a minimum length of 1.5 m, with a minimum of 10 compartments. • Take samples in the areas marked by X in the truck diagram shown below. The probe should go as deep as possible to obtain product from multiple layers of the load. • Most modern plants have pneumatic and automatic probes that take the samples directly. • The more sample points you have, the more accurate the results will be. 2. At the reception area (grains and raw materials) For effective sampling at the reception area, follow this step-by-step process: • From the samples taken from the incoming trucks/ cars, take 21 sub-samples of 200 g each (4,200 g total). • Mix these 4,200 g and divide in half (2,100 g). • Mix and take half again (1,050 g). • Out of the 1,050 g obtained, send 500 g to the lab for testing. 3. In the feed mill and storage warehouse During the manufacturing process, take representative samples after grinding and before mixing. Don’t forget to continue sampling the prepared feed while it is in the storage warehouse. Size of the composite sample, according to EU recommendations 20 - 50 MT load = 10 Kg of composite sample To reduce sampling variability, take two 5 kg composite samples per truck 13 - 20 MT load = 6 Kg of composite sample
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