Cleaner Broiler Carcasses

The NRC funded project "Cleaner chickens" is a collaboration between Norsk Kylling AS as the project owner and RD institutions being the Norwegian Veterinary Institute, Norwegian University of Life Science and Animalia.

Background and objectives

Background for the project "Cleaner chicken slaughter" are known challenges in chicken production regarding the occurrence of Campylobacter infection in chickens, too high a proportion of slaughter that is discarded due to faecal contamination through the slaughter process and a need to improve biosecurity on farms. The aim of the project was to find effective measures along the value chain that can help reduce the bacteria level in chicken slaughter. This could lead to less wastage at the butchery due to fewer discards of whole slaughter and contribute to longer shelf life of the poultry products, which in turn leads to reduced food wastage in the shop and with the consumer.

Achieved results

The "Cleaner Broiler Carcasses" project has carried out activities as planned in the project description. There were three defined work packages in the project, including experiments and recordings on farms, hygiene measures for transporting chickens to the slaughterhouse, and experiments at the slaughterhouse. The project has resulted in new knowledge about the use of rapid methods for detecting Campylobacter in live broiler chickens. These are valuable contributions to the Action Plan against Campylobacter, although further testing of rapid methods is needed before conclusive statements can be made about the effectiveness and safety of the new analytical method.

In the project, a new protocol for the Hygiene Performance Rating (HPR) on farms was developed. This protocol was used in 2021 for recordings related to infection control and biosecurity at 30 poultry producers in Trøndelag. The recordings showed encouraging results with generally good infection control on the farms. The Hygiene Performance Rating on farms will be a useful tool for working systematically and in detail with infection control. The routine use of the Hygiene Performance Rating on farms by poultry producers will be further investigated. In this project, an examination was conducted to determine if there was a correlation between farms that frequently experience Campylobacter contamination in flocks and a poor score in the Hygiene Performance Rating. It turned out not to match. 

Campylobacter infection still has unclear routes of infection into chicken flocks, via water, insects, feed, and general contamination from the environment, as international literature also describes. Testing of insect nets on farms with recurrent Campylobacter infection showed interesting results with a reduced incidence of Campylobacter in the season where insect nets were installed. It would be appropriate to test insect nets over several coming seasons to see if this positive trend continues and is stable. Good drinking water quality for broilers is important for animal health and food safety.

The project conducted sampling and recording of drinking water quality by testing water for indicator bacteria and mapping water sources, disinfection methods, and maintenance of drinking water systems. Preliminary results indicate that there was good drinking water quality in the sample during the experiment, but there is room for improvement in the operation and maintenance of drinking water systems. A tailored and enhanced cleaning procedure for transport containers was established during the project period. The project owner, Norsk Kylling, derived significant benefits from the adapted cleaning procedure at the old slaughterhouse, making it a practical and valuable outcome that was directly implemented during the project period.

Furthermore, the project conducted testing of four sampling methods for broiler carcasses to determine the best recovery of indicator bacteria. It was concluded that rinsing of whole carcasses yielded the best recovery, but this method is time-consuming. Alternatively, the analysis of neck skins proved to be a quicker and simpler method for regular sampling routines in slaughterhouses. Whole carcass rinsing was used as the method for testing decontamination with hot water. Decontamination with hot water or organic acids is common in poultry slaughterhouses in the USA but not in Europe. There was a relatively good effect of using hot water for decontamination, and dipping the carcasses in 80°C water for 6 seconds yielded the best results. The use of a 5% lactic acid solution significantly reduced bacterial levels on the carcasses. Currently, this is not legally permitted for use on chickens, only for beef and small ruminants. These results are crucial for the cost-benefit analysis of decontamination and proposals for alternatives for a two-step product flow to reduce food waste.

An activity in the project involved describing bacterial quantity and dynamics along the slaughter line. This work was conducted in two slaughter lines through a pilot study in 2020 and the main experiment in 2021. The results were consistent with international studies in the field but also provided new knowledge about bacterial communities along the slaughter line through 16S rRNA sequencing. This type of mapping has not been done in Norway before. This knowledge demonstrates the effects of various measures on the slaughter line, such as scalding at different time/temperature combinations and cooling regimes. This will be valuable information for other poultry slaughterhouses as well. A new method for risk categorization of slaughterhouses was implemented, which can be used by the Norwegian Food Safety Authority for assessing the frequency of inspections. This information contributes further to European collaborations (RIBMINS COST Action).

Most important R&D tasks completed

Research and development participants in the project included NMBU (Norwegian University of Life Sciences) and the Veterinary Institute. NMBU conducted experiments using rapid methods for detecting Campylobacter, including the establishment of experimental protocols, analysis execution, and primary responsibility for writing scientific publications. The Veterinary Institute analysed samples from the slaughter line dynamics experiment using 16S rRNA and indicator bacteria, providing valuable insights into processes on a slaughter line that can reduce bacterial contamination of carcasses.

Implementation of the project and use of resources

The "Cleaner Broiler Carcasses" project was carried out during the corona pandemic, but has still managed to deliver results in accordance with the planned activity. A significant reason for the project's successful progress despite restricted access to the slaughterhouse for external project participants is that personnel from Norsk Kylling have conducted many of the sampling tasks in the project after training via Teams and written instructions. This ensured infection control while allowing us to carry out experiments. Budget funds have been utilised as planned, and there have been sufficient resources to execute all planned activities in the project.

Utility and significance of project results

Slaughter hygiene in poultry slaughterhouses has not previously been scientifically investigated in Norway in the same way as in this project. Infection control and biosecurity on the farm have also been systematically investigated. Food chain information throughout the value chain is becoming increasingly important for food safety. The "Cleaner Broiler Carcasses" project has identified important areas that the company in the project can work on to reduce the occurrence of Campylobacter-positive chicken flocks, improve slaughter hygiene and work further with opportunities to use decontamination of slaughter carcasses to reduce food waste.

Dissemination and utilisation of results

Three scientific articles have been published during the project period, and the results of experiments have also been disseminated through various relevant forums, including conferences, seminars, and in national journals for poultry producers. There has generally been a good interest in the project results.

Results that are finalised after the end of the project

For the work on Hygienic accounting farm, a scientific article will be published about the results. For the experiment with decontamination of slaughter, a scientific article was published in the first quarter of 2023. The drinking water experiment was carried out in autumn 2022, and results from this the trial will also be published. The cost-benefit analysis on the use of decontamination to reduce the proportion of discarded carcasses due to faecal contamination is planned to be carried out after the project

Read more on the project database at the Research Council of Norway (NFR) here.