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The Carry Over Control Procedure, to Guarantee the Quality of Animal Feed Logo Feedia

The carry over control aims to ensure livestock feed safety and to guarantee the compliance of animal feed with regulations. Still, this control is above all an a priori procedure, which does not eliminate the need for constant vigilance. How does this control plan allow us to better secure the production route for animal feed?

We no longer speak of “cross contaminations” but of “carry over”. This expression is less alarming and more appropriate. Indeed, animal feed is often produced on one single production line although it is intended for animals of different ages and species. It can sometimes happen that when certain compounds are transferred from one batch to another, a residual amount of a batch can be found in the following or previous batch. The issue is not strictly speaking about the contamination of one batch by another, but it rather relates to regulatory and zootechnical thresholds that must not be exceeded. These tolerance levels are calculated and controlled according to the species that will consume the feed concerned. Infrastructures and equipment currently available in feed mills cannot totally prevent carry over from occurring. This is why a control plan is absolutely necessary for all feed milling processes.

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Four reasons for a carry over control

What is the purpose of this control procedure?

  • To guarantee animal feed safety
  • To better comply with the directive 2009/08/CE: this directive sets the maximum levels of cocciodiostats in feed for non-targeted species. It was updated with the regulation 574/2011 of June 2011
  • To comply with good practice guides (GBP Feed annex 5, GMP...)  
  • To maintain production lines in good working order

The current protocol

A strict protocol must be respected to correctly estimate the residual quantity of a feed milling process. In France, it is the Tecaliman protocol, used in the Best Practices for Feed Guide that is recommended in this framework (see Annex.4 Technical Rules for assessment of the level of cross-contamination between feeds). This control protocol applies to conditions for the most commonly manufactured feeds (without necessarily looking for extreme conditions). However, for this test to take place properly, several batches need to be planned. 5-6 mixtures must be represented as follows: at least one control batch, a “white”, two “tracer” batches and two “collectors” (batches recovering the amounts of tracer stayed in the tested line). If possible, these batches should be of similar size and made of the same feed, which is not always easy to plan.

How to build this control?

We can also use the second batch with the tracer to proceed to the mixing control (homogeneity check) of the compound feed according to the same protocol. In this case, what size of batch should be used ? Should we work with large batches including tracer, followed by “small” collector batches, or vice versa? Or should the batches be of the same size? The order of batches should be mainly reflected depending on the context of the feed mill. The most important thing is that the compound feed should be checked while it is still in the feed mill circuit, before being given to the animals; samples should be taken as close as possible to the final distribution of the feed. Each production line should undergo an annual carry-over control.

The carry over control is an a priori  procedure        

Yet, the carry over control remains an a priori procedure. It does not guarantee possible non-conformities with regards to the regulations. What does this mean?  Notably, that stage cannot completely prevent carry-over with undesirable substances especially like coccidiostats (directive 2009/08/EC ).

Do you want to ensure the quality of your feed and secure your production process? Whether its advice or assistance in the implementation of your carry-over control plan, our Feed Formulation, Feed Mill Technology and our laboratory are able to assist and recommend corrective actions in case of any deviations detected following results. For more information, do not hesitate to contact our experts !

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