Guidance for the assessment of detoxification processes in feed

2.2. Efficacy of the process

Several feed detoxification processes that detoxify feed have been described in the literature. The principal task of the FBO is to demonstrate the efficacy of their application of the process at an established plant for feed to which the process will be applied. The efficacy may initially be demonstrated in a pilot plant, but it is important to show that the process is transferable and reproducible on an industrial scale.

2.3. Reversibility of the detoxification process

The FBO should consider if the process may be reversible meaning that the levels of the undesirable substance can increase again in the feed or inside the animal.

It is unlikely that a physical process of detoxification, where the undesirable substances are removed, will be reversible and therefore no evidence is required to demonstrate reversibility of physical detoxification processes.

In the case of a chemical or enzymatic process where the degradation products are not removed, these may revert to the target compounds. These can be evaluated in the feed. The applicant should demonstrate that the process is not reversible when the feed is processed, stored or when offered to the animals. In addition, on a case‐by‐case basis, the irreversibility should be confirmed in the target animals fed with decontaminated material followed by analysis of tissues, milk or eggs. In vitro digestion models may be helpful in these studies as a first step.

2.4. Safety of chemical and (micro)biological agents used

If the FBO demonstrates that the residues of the detoxification agents and their metabolites of concern (physical, chemical or (micro)biological) are not detectable in the detoxified feed, safety data will not be needed. Analytical data to demonstrate the absence of the residues in the detoxified feed can be obtained from the samples used in the efficacy studies with the use of up‐to‐date analytical methods.

In case residues remain in the feed product, information on the safety of the agents and their metabolites for the animals fed the feed, the consumers of food products from these animals and for the environment is needed.

Regarding the application of physical and chemical processes, residues of the applied chemicals used could be solvents, adsorbants or other chemical agents (e.g. impurities, metabolites) in the detoxified feed. In case legal limits have been set for the chemical agents to be used, the FBO should demonstrate that these will not be exceeded in feed and in food produced from animals consuming this feed. For other chemicals, a basic set of data from toxicological studies may be required to demonstrate the safety of the chemicals for animals and humans (genotoxicity, sub‐chronic toxicity studies augmented as appropriate by other studies e.g. chronic, reproduction, carcinogenicity etc. studies, on a case‐by‐case basis).

The use of strains of microorganisms belonging to a species that qualifies for the QPS approach (EFSA, 2007; EFSA BIOHAZ Panel, 2023) and for which the qualifications were met, are considered safe for the animals, humans and, if relevant, for the environment and therefore no further data are required.

It is noted that microorganisms such as bacterial strains carrying acquired genes that confer resistance to relevant antimicrobial(s) or pathogenic, virulent or toxigenic strains and those capable of producing relevant antimicrobials may represent a risk for the target animals and humans.

Safety data in animal species may be required taking into consideration the identity and the characterisation of the microorganisms and this could include literature information, toxicological tests or studies in the target animals (following for example the principles of the guidance on the safety for the target species in the Feed Additives area [EFSA FEEDAP Panel, 2017]). The safety for the consumers of food products obtained from the animals may also need to be addressed (e.g. with a basic dataset of genotoxicity and sub‐chronic oral toxicity study).

For enzymes, if the enzyme is present at the end of the process and/or depending on its nature, the source and the preparation, data on the safety for the animals and the consumers of food products obtained from these animals may be required. For example, a basic set of toxicity studies (genotoxicity and sub‐chronic oral toxicity studies) may be relevant.

2.5. Toxicity of products formed during the detoxification process

In any detoxification process, when degrading undesirable substances without any removal of the degradation products, it is in principle required to examine which degradation products are formed and especially if they could present a risk to the target animal or the consumer due to residues in animal‐derived products. Degradation products might be identified using a labelled standard of the target compound added to feed material. Another option is the treatment of a pure standard followed by identification and analysis of the degradation products in the treated commodities. However, degradation products may also react with feed materials. The toxicity of the individual degradation products should be tested.

In practice, it may be not possible to identify degradation products of the undesirable substance(s), especially in the specific matrices. In such cases a more pragmatic approach may be followed by performing appropriate toxicological testing on the product or product extracts before and after the treatment, e.g. genotoxicity evaluation of the extracts of the treated products and/or the identified degradation products. It should be demonstrated by appropriate testing that the process is able to provide a substantial detoxification.

For microbiological based detoxification applications, additional biohazard considerations apply, including the possibility that the microbes used may produce toxins. These should be addressed in accordance with the toxigenicity and pathogenicity requirements of the Section 2.4 of the Guidance on the characterisation of microorganisms used as feed additives or as production organisms (EFSA FEEDAP Panel, 2018) and section 3.5.3 of the Statement on the requirements for whole genome sequence analysis of microorganisms intentionally used in the food chain (EFSA 2021).

2.6. Characteristics and nature of the processed feed

The feed detoxification process should not adversely affect the nutritional value of the feed. The FBO should provide evidence that the detoxification process does not compromise the nutritional value of the product. This evidence should include analysis of at least three samples from three batches of a specific feed before and after detoxification with pre‐ and post‐treatment samples taken from the same batch. For example, such evidence could be provided for the fatty acid composition of fish oil treated with charcoal to remove chlorinated dioxins (EFSA CONTAM Panel, 2017). Depending on the feed, it should be shown that the levels and the profile of essential nutrients are not adversely affected (e.g. fatty acid profile and contents of vitamins for fish oil treated with charcoal).