ID-9-P-2460 Use of stereological methods for detecting destructured zones in cooked hams

Destructured zones in cooked hams have recently been a major problem for meat industry where they cause significant economic losses. Occurrence of destructured zones in cooked hams is reported between 2-20 per cent. Destructured zones are typically inappropriate for cutting after the heat treatment due to reduced cohesion and they characterized by wavy structure and disrupted muscle fibers. Literature reports that these defects are caused by the quality of meat, especially when PSE (pale, soft, exudative) meat is used. It has been described that these differences in quality of raw materials are caused by different biochemical and physical properties, when muscle myofibrillar proteins are denatured, meat has poor water-holding capacity, has a lighter color, and the texture of the final product is changed. PSE in meat can be determined using a number methods, including methods of muscle fibers microstructure analysis. A possible cause of destructured zones is abnormally rapid post-mortem glycogenolysis, which is also reflected in the increased formation of lactic acid. The cause of destructured zones can also be the technology applied (Valous et al., 2009). The aim of this work was to verify the possibility of distinguishing destructured and non-destructured zones at the microscopic level using stereological methods. In this work, histological examination of cooked hams was utilized with evaluation using a point grid (Ellipse, SVK). Three samples were taken from destructured zones and three samples from non-destructured zones for this research. The samples were processed using paraffin blocks and stained with haematoxilin-eosin staining (Bancroft, 2008). The examination was performed by means of Nicon Eclipse E200 microscope (Nikon, JPN). During the examination of samples using the light microscope, significant differences in the structure of skeletal muscles were observed, namely disorganization and rearrangement of muscle fibers were found in destructured zones. Stereological examination demonstrated a significant difference in the representation of transverse and longitudinal fissures (p≤0.05). In non-destructured zones, transverse fissures were detected in the muscle fiber in the proportion of 4.39 per cent, whereas longitudinal fissures were not observed at all. Nevertheless, in destructured zones, transverse fissures in the proportion of 47.6 per cent and longitudinal fissures in 6.11 per cent were detected in the muscle fiber. Similar changes are also described by Laville et al. (2005) who evaluate them as typical for PSE meat. The results thus show that histological examination can distinguish between destructured and non-destructured zones in ham on the basis of the proportion of transverse and longitudinal fissures.