Handling of chronic cases of pyaemia/osteomyelitis in finishing pigs in Denmark – is de-boning necessary to maintain food safety?

Meat inspection is up for debate and one issue deals with how to handle chronic cases of pyaemia/ osteomyelitis in finishing pigs. In Denmark, such carcasses are required to be de-boned to avoid presence of osteomyelitis not found in the rework area. Around 40,000 pigs (0.24%) are subjected to de-boning in Denmark per year, and the associated costs amount to approx. €3 million. The questions are: 1) is the meat from such pigs fit for human consumption? 2) Is de-boning necessary, or do the meat inspectors find what they should in the rework area? And 3) which alternative practices could replace de-boning? To address this, data covering 1 year were extracted from the Danish Slaughterhouse Database including information from the 7 largest Danish abattoirs. Registration schemes covering findings during de-boning and the result of de-boning (approved/ condemned) were provided by the individual abattoirs. Additionally, a questionnaire survey was undertaken regarding the de-boning personals’ experience related to de-boning. Furthermore, samples from 102 pigs sent for de-boning at one slaughterhouse were collected. These samples included abscesses found in pigs at the rework area plus one muscle sample per pig. All samples underwent microbiological investigation. As a control group, microbiological results obtained from a similar study from carcasses unconditionally approved at meat inspection were included. Staphylococcus aureus, which has the potential to cause human illness, was found in 15 abscesses and 1 muscle of the 102 pigs sent for de-boning. S. aureus was also found in 1 of the 60 control samples. The results were included in a risk assessment that revealed the same very low health risk related to consumption of meat from de-boned pigs as from fully accepted pigs. Abscesses were found at de-boning in a low proportion of the pigs, at different sites of the carcass, varying between abattoirs. The vast majority of pigs sent for de-boning were accepted after de-boning (99.7%). If routine de-boning is no longer required, then focus on a thorough inspection at the rework-area will most likely result in a higher probability of finding abscesses at that stage of inspection. Moreover, overlooked abscesses will be found during cutting. Therefore de-boning is not considered necessary and could be replaced by condemnation of the affected part(s) only.