Causes and Bacteriological Findings in Carcasses Condemned at a Danish Broiler Abattoir

PhD Student: Ahmed Eassa H.  Alfifi
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Modernization of meat inspection has been debated within the EU for the last decade with the aim of achieving new knowledge about control of the relevant hazards and not using resources on matters that are no longer of importance. One of the first steps to ensuring food security is curbing food wastage, which in turn helps facilitate resource conservation and a reduction in the environmental footprint of food production. Slaughterhouse condemnation, however, remains a major challenge in EU countries, where it represents the second largest proportion of whole food waste. The current practice of meat inspection needs to be improved, and this can be achieved through the implementation of guidelines that require an investigation of the root causes of observed lesions and outline recommendations for cases that qualify for partial or total condemnation. This could potentially reduce the amount of food wasted due to unnecessary carcass condemnation. Furthermore, in Denmark, robust data on the entire poultry production value chain are available and can be leveraged for the implementation of policies to improve the production process and reduce the occurrence of diseases leading to wastage. The available data would provide insights on, amongst others, the association of disease prevalence with varying farm management practices and thus allow the design of tailored and efficient mitigation strategies to curb the incidence and spread of poultry diseases.

The overall aim of this Ph.D. project was to determine the causes of carcass condemnation in Danish broiler production inform the modernization of current meat inspection practices and ultimately reduce food wastage in the broiler value chain. 

Three main studies were performed with the following specific objectives:

Study I:

  1. To determine the prevalence of pathological lesions in Danish broilers using the meat-inspection data from the quality assurance system in the Danish broiler production (KIK) database
  2. To analyze three causal models for 'dermatitis,' 'arthritis,' 'systemic infection,' and the possible explaining factors of footpad lesion, age at slaughter, scratches, and thinning of the flock

Study II:

  1. To determine the microbial aetiology of the common disease conditions resulting in carcass condemnation of Danish broilers.
  2. To characterize the genetic diversity and zoonotic potential of the dominant isolated bacteria from the investigated lesions of individual carcasses.
  3. To evaluate conditions for requiring total condemnation in poultry carcasses

Study III:

  1. To characterize the phylogenetic diversity, antimicrobial resistance profiles, and pathogenic potential of A. veronii strains isolated from Danish broiler carcasses


In study 1, we estimated the prevalence of pathological lesions in Danish broilers based on three years of data on meat inspection reports obtained from the Danish Quality Assurance System database. A total of 1,420,812 carcasses were condemned during the study period, representing 1.1% of the total poultry production over that period. The most common reason for carcass rejection was skin lesions, which made up 56.3% of all condemned carcasses. The second most common reason for carcass condemnation was ascites (24.7%), followed by discoloration (9.8%), emaciation (9.6%), hepatitis (9.6%), and arthritis (7.6%).

Microbiological assessment results of the 400 collected carcasses of cellulitis, scratches, acute hepatitis, and healthy control (each code/control group n=100) revealed that a total of 469 bacterial isolates were recovered from different sample types. Bacteria were more frequently isolated from carcasses condemned with cellulitis (184/469) as compared with carcasses condemned with hepatitis (69/469). E. coli was the main isolated bacterial species from all sample types from condemned carcasses, indicating that infection caused by E. coli is the main cause of carcass condemnation in Danish broilers. A clonal relationship was found between E. coli isolated from different sample types of the same carcass condemned with cellulitis and scratches. A dominant clade including 12 isolates was found to be closely related and primarily associated with systemic infection. Isolates from this clade belonged to ST117 and clustered together with strains isolated from diseased and condemned broiler carcasses from Scandinavian countries and UK.

 The highest reported causes of condemnation were found to be among the emerging diseases that are related to fast-growing broilers. This was as a result of continued efforts on improving the growth rate of chicken, which leads to imbalanced body development in muscle and other body systems. Hence, further research needs to be conducted to balance the growth rate of poultry meat with other body systems (especially the skeleton and cardiac systems). This will enhance the broiler's health production and welfare. 

Bacteriological findings of carcasses condemned due to cellulitis, acute hepatitis and scratches (moderate to severe scratches lesions) revealed the needs of total condemnation of carcasses with these conditions. Further investigation need to be done to assess the need for condemnation for carcasses with chronic hepatitis and mild scratching lesions.  

During the study, it was noted that performing error-free post-mortem inspection of poultry is challenging under the current slaughter speed, which is more than three carcasses per second. Therefore, there is a need to develop and apply new technologies that work with full efficiency to adequately monitor inspection at this speed to avoid chances of error during meat inspection. The inspection vision system can be deployed; however, further researches are needed to evaluate the efficiency of this system when compared to current meat inspection practice.