IDENTIFICATION OF MEAT QUALITY DEFECTS IN PIGS OF DIFFERENT GENOTYPESUSING VARIOUS METHODS OF EVALUATION

Rapid and very accurate detection, if possible, of pork quality defect s is at present important particularly in the process of carcass class ification for successive processing in the meat industry. The aim of t he study was to determine the meat quality in pigs of different geneti c constitution using various methods of evaluation, as well as to anal yze relationships between the used methods. Meat quality was determine d in a group of 148 pigs of three genotypes (White Pork /WP/; syntheti c line /Belgian Landrace x Duroc/; hybrids /WP x D x Yorkshire/) while various methods of evaluation (acidity, electrical conductivity - EC, colour, water-holding capacity) were used. In addition, correlation c oefficients were calculated to evaluate nearness of relationships betw een the used methods of meat quality determination. The pigs were hous ed and fattened under identical conditions, as well as their slaughter and handling with sides of pork were identical and in agreement with standard conditions. The results have confirmed that the pigs had rela tively good characteristics of meat quality at the average slaughter w eight of 110.3 kg (Tab. II). Table III shows the nearness of correlati on coefficients calculated for the whole group altogether. There were highly significant correlations between electrical conductivity measur ed 45 minutes postmortem (EC1) in the m.Ld and EC1 in the m.s.m. (r = 0.72). Medium-high dependence were calculated between pH1 and meat col our determined on a GOFO apparatus (r = 0.34), pH1 and water-holding c apacity (r = -0.27), as well as between pH1 and meat colour determined by means of a Japanese scale (r = 0.48). In the next section of the s tudy the analyzed groups of pigs was divided into subgroups with PSE m eat defect (pH1 < 5.8; electrical conductivity > 8.3; GOFO less-than-o r-equal-to 60) and without this defect (pH1 greater-than-or-equal-to 5 .8; EC less-than-or-equal-to 8.3; GOFO > 60). Tab. IV shows mathematic o-statistical characteristics of the traits in the given subgroups, an d also the significance of differences in the investigated traits (t-t est). As for the values of correlation coefficients in these subgroups (Tabs. V and VI), their nearness was larger in the subgroup of PSE pi gs, and this suggests that the utilization of electrical conductivity is important particularly in individuals with worse meat quality. Thes e correlation coefficients were determined: r = -0.51 for the relation ship between pH, and EC1, r = -0.62 for EC, and GOFO, r = -0.50 for EC 24 and GOFO, and finally r = 0.37 for pH1 and GOFO. Narrow relationshi ps between the GOFO values and the Japanese scale values is a very imp ortant finding (r = 0.65 to 0.68), and this reveals the prospects of J apanese scale use for expeditious determination of meat colour. Tab. V shows the basic characteristics of the evaluated parameters of meat q uality in pigs of different genotypes. The results document that the p igs of the synthetic line (crossbreds of Belgian Landrace and D) had t he worst meat quality while hybrid pigs and the dam breed White Pork h ad the best parameters. The hybrid pigs (boars of Large White Dutch br eed were in the position of final hybrid sires) and pigs of White Pork breed had the lowest portion of PSE meat, while the pigs of the synth etic line had the highest portion of this meat. The results of the exp eriments have confirmed the good prospects of electrical conductivity use for PSE meat detection, while the advantages of the TECPRO QM appa ratus can be profited from: massive stabs, clearly arranged display of value readings, no need of calibration. Determination of statisticall y highly significant correlation coefficients in pigs with PSE meat de fect demonstrated the narrow relationship of electrical conductivity v alues to other indicators of meat quality. The values of electrical co nductivity, and also other methods of meat quality determination, are applicable in practical operating conditions, and they can provide rel atively high accuracy of PSE meat identification in pigs.