Classification of Vertebral Osteomyelitis and Associated Judgment Applied during Post-Mortem Inspection of Swine Carcasses in Portugal

Abstract

Vertebral osteomyelitis (VO) it is often a suppurative lesion that, in Portugal, represents the main cause of total condemnation of slaughtered finishing pigs. Based on the EU Meat Inspection legislation, meat from generalized VO cases presenting signs of pyemia should be declared unfit for human consumption. For that reason, the main objective of this study is to establish a classification scheme to differentiate between localized and generalized VO cases using macroscopic findings and validate it based on the presence of pyemia. To assist in, a combination of macroscopic characteristics of gross lesions (e.g., presence of pyaemia-related lesions (PRL), acute/chronic characteristics of VO) was used to create a classification scheme to differentiate between localized and generalized VO cases. The scheme was applied to 40 VO cases that had been totally condemned in an undifferentiated way. In those 40 cases, histopathological analysis was used to validate acute/chronic macro-criteria, and microbiological analysis was performed to identify the pyemia cases. From the 40 selected VO cases, 20 were macroscopically classified as chronic and 20 as acute. Cohen’s kappa coefficient (κ = 0.80; p < 0.001), revealed a substantial agreement between macroscopic and histopathology classification. Microbiological analyses identified 13 pyemia cases (13/40; 32.5%). Among those, 12 were macroscopically classified as acute, this association being highly significant (p < 0.001). By using the proposed VO classification scheme, 14 possible cases out of 40 could have been spared from total condemnation. This scheme can be used to harmonize the classification of VO and meat inspection decisions in Portuguese abattoirs. The output would lead to avoidance of unnecessary carcasses condemnation (food waste/economic losses), under an evidence-based approach, without compromising food safety and public health as demanded by the EU Meat Inspection legislation.