The use of high expansion foam for stunning and killing pigs and poultry

Background to the opinion

• Pig and poultry farmers, as well as veterinary competent authorities, require humane methods for stunning and killing animals on farms, which include routine slaughter and culling due to infectious disease outbreaks.
• This opinion analyses Nitrogen (high) Expansion Foam Stunning in container (NEFS in container), an innovative method that aims to humanely kill pigs and poultry by creating a low-oxygen environment.
• Currently, using NEFS in container is not allowed for stunning and killing animals in the EU. However, Council Regulation (EC) No 1099/2009 lists approved stunning methods and allows the European Commission (EC) to update this list based on an EFSA scientific opinion.
• Before this opinion, EFSA first considered the use of gas-filled foam for killing poultry in 2019 and pigs in 2020, without carrying out a full risk assessment.

What was EFSA asked to do?

• At the request of a private company (applicant), the European Commission (EC) asked EFSA's Panel on Animal Health and Animal Welfare (AHAW) to evaluate scientifically the use of NEFS in container for stunning and killing pigs and poultry. 
• As per Article 29 (1) (a) of the European Parliament Regulation (EC) No 178/2004, EFSA had to assess the following:
  • Eligibility - Did the applicant’s dossier, proposing the modified stunning method, meet EFSA's relevant established guidance?
  • Animal Welfare - Could this method ensure a level of animal welfare that either meets or surpasses the standards set by existing approved methods? Specifically, EFSA was asked to determine if the method spares pigs and poultry from any unnecessary pain, distress or suffering during the killing process, and if it ensures they remain unconscious until death.

How did EFSA carry out this work?

• EFSA formed an ad hoc working group to: 
  • check the provided data against the criteria laid down in the EFSA Guidance on the assessment criteria for applications for new or modified stunning methods regarding animal protection at the time of killing (EFSA AHAW Panel, 2018)
  • conduct an extensive literature search
  • extract data for quantitative assessment
  • perform a qualitative exercise based on non-formal expert elicitation.
• In the submitted dossier there was an analysis of two published scientific studies that were considered in the assessment. EFSA requested additional information to clarify details about the data and information provided for the stunning method.
• The data gathered also included ongoing research and unpublished field trial data. However, these data comprised only basic summaries of the research and could not be used for the assessment.

What were the limitations/uncertainties?

• It was difficult to compare different group and individual stunning/killing methods. This potentially disadvantaged group methods, as the number of animals affected simultaneously by potential hazards is higher in group methods, which aim for gradual loss of consciousness, in contrast to individual methods.
• The uncertainty analysis of expert findings was based on individual expert judgment (EFSA, 2014) and the overall uncertainty assessment was done according to the EFSA Guidance on Uncertainty Analysis in Scientific Assessments (EFSA Scientific Committee, 2018a, b). 
• There was uncertainty about the performance of killing/stunning methods that had not been extensively researched.
• There were sufficient data to advise only on the welfare of laying hens and broiler chickens of all ages, and pigs weighing between 15 and 41 kg.

What were the outcomes?

• Alternative for on-farm killing: NEFS in container offers a humane alternative for on-farm killing, for situations other than slaughter, such as during an infectious disease outbreak. However, for NEFS in container to be effective, it is essential to ensure proper implementation through the technical conditions specified, staff training and procedure monitoring.

The AHAW Panel concluded with a certainty of >50-100% (more likely than not)^[1]that:

• Welfare comparable to existing methods: NEFS in container seems to offer a level of animal welfare at least equivalent to existing approved methods, such as high-concentration carbon dioxide exposure and electrical water baths.
• Animals are spared avoidable stress: Animals exposed to NEFS in container did not show signs of mucosal irritation, nor did they cough or choke. This implies that the foam does not enter their upper respiratory tract while they are still conscious, thus avoiding unnecessary stress.
• Humane stunning and killing: Used correctly, NEFS in container appears to be at least equally effective as currently legally permitted container gas methods, avoiding pain, distress and suffering for animals during stunning and killing.

What are the key recommendations?

• Ensure adequate staff training: People handling the equipment and animals need proper training and certification to perform the procedures humanely.
• Use proper equipment setup: The equipment must be set up correctly and used according to the Standard Operating Procedures (SOPs).
• Check water quality: The water quality should be controlled to ensure it is suitable for making uniform foam.
• Use automated control systems: Any automated system should check all important settings of the key parameters before NEFS in container is used, to ensure everything is safe and functional.
• Implement proper procedures: Animals must be put in the container only when ready for immediate processing. The nitrogen gas and foam solution should be double-checked before starting. The container should be filled with foam in less than a minute to avoid potential adverse welfare outcomes for the animals. The nitrogen jet stream should be directed towards the sides of the container and not towards the animals. The animals should be dead before opening the container for which a reliable monitoring system is required. Oxygen levels should stay below 2% throughout the process. Oxygen sensors should be regularly tested and the gas system should be protected from freezing in cold weather. 
• Provide available backup killing methods: As with all stunning methods, in case the NEFS system fails to function properly, another appropriate killing method for pigs or poultry should be available.
• Do not overload containers: The container should not be overloaded, all animals should have enough space to lie down, to allow the foam to reach all the animals and prevent air pockets.
• Perform additional research: More research is needed to confirm the findings, to extend the application of this method to other categories of poultry (for example ducks and pigeons) and other types of pigs (i.e. of different weights other than specified above).

Glossary

Stunning methods: Any intentionally induced process which causes loss of consciousness and sensibility without pain including any process resulting in instantaneous death. 

Disclaimer

• This plain language summary (PLS) is a simplified communication of EFSA’s scientific opinion titled The use of high expansion foam for stunning and killing pigs and poultry. The full EFSA opinion can be found here.
• The purpose of the PLS is to enhance transparency and inform interested parties on EFSA’s work on the topic using simplified language to present a summary of the main findings.

Reference

EFSA (European Food Safety Authority), 2014. Guidance on Expert Knowledge Elicitation in Food and Feed Safety Risk Assessment. EFSA Journal 2014;12(6):3734, 278 pp. https://doi.org/10.2903/j.efsa.2014.3734

EFSA AHAW Panel (EFSA Panel on Animal Health and Animal Welfare), More, S., Bicout, D., Bøtner, A., Butterworth, A., Calistri, P., Depner, K., Edwards, S., Garin-Bastuji, B., Good, M., Gortazar Schmidt, C., Miranda, M. A., Nielsen, S. S., Velarde, A., Thulke, H., Sihvonen, L., Spoolder, H., Stegeman, J. A., Raj, M., … Michel, V. 2018. Guidance on the assessment criteria for applications for new or modified stunning methods regarding animal protection at the time of killing. EFSA Journal 2018;16(7):5343, 35 pp. https://doi.org/10.2903/j.efsa.2018.5343

EFSA Scientific Committee, Benford, D., Halldorsson, T., Jeger, M.J., Knutsen, H.K., More, S., Naegeli, H., Noteborn, H., Ockleford, C., Ricci, A., Rychen, G., Schlatter, J.R., Silano, V., Solecki, R., Turck, D., Younes, M., Craig, P., Hart, A., Von Goetz, N., Koutsoumanis, K., Mortensen, A., Ossendorp, B., Germini, A., Martino, L., Merten, C., Mosbach-Schulz, O., Smith, A. and Hardy, A. 2018a. Scientific Opinion on the principles and methods behind EFSA’s Guidance on Uncertainty Analysis in Scientific Assessment. EFSA Journal 2018;16(1):5122, 235 pp. https://doi.org/10.2903/j.efsa.2018.5122

EFSA Scientific Committee, Benford, D., Halldorsson, T., Jeger, M.J., Knutsen, H.K., More, S., Naegeli, H., Noteborn, H., Ockleford, C., Ricci, A., Rychen, G., Schlatter, J.R., Silano, V., Solecki, R., Turck, D., Younes, M., Craig, P., Hart, A., Von Goetz, N., Koutsoumanis, K., Mortensen, A., Ossendorp, B., Martino, L., Merten, C., Mosbach-Schulz, O. and Hardy, A. 2018b. Guidance on Uncertainty Analysis in Scientific Assessments. EFSA Journal 2018;16(1):5123, 39 pp. https://doi.org/10.2903/j.efsa.2018.5123

The use of high expansion foam for stunning and killing pigs and poultry
DOI: https://doi.org/10.2903/j.efsa.2024.8855