MEAT QUALITY IN PIGS - COMPARATIVE INVEST IGATION IN CONSIDERATION OFPRELIMINARY FACTORS OF STRAIN, CARCASS WEIGHT AND LEAN MEAT PERCENTAGE

The factors of strain that pigs destained for slaughter are put under do not only have an effect on the health and welfare but also on the m eat quality of the beasts. For the early post-mortal measurement of me at quality various testing methods are known all of which can be evalu ated differently. The goal of this research was to test the usefulness of different meat quality parameters (such as pH, conductivity (LF) a nd colour) in order to be able ro recognize PSE-meat on the slaughterl ine under practical conditions. Through appointing preliminary factors of strain which had to be easy to register it was at the same time in tended to check whether there is a direct correlation between these pa rameters and the resulting meat quality. From Jan. 6th 1992 to July 10 th 1992 4806 hybrides, which were taken from 232 different fattening g roups and 87 different carriers were measured in the M. longissimus do rsi as well as in the M. semimembranosus and the colour of the M. semi -membranosus was evaluated in one half of the carcass 42 to 45 minutes p.m. directly on the slaughtering line. Furthermore the percentage of lean meat, the carcass weight as well as preliminary factors of strai n such as duration of transport, loading density, lairage time and hum idity factor were noted. The interrelation of the measured meat qualit y parameters were as followes: Most pigs with PSE-features in the exam ined parts are found by measuring the pH. Simply one third (ham) resp. about one half (loin) of the PSE-features are noticed by measuring co nductivity. Through evaluating the colour of ham only one percent PSE is discovered in contrary to 13% discovered with the help of pH-measur ement. The biggest coherance of pH and LF (66.5% ham, 65.5% loin) exis ts when meat is suspected of being of PSE-quality. The smallest cohera nce is shown with meat of PSE-quality (20.2% ham, 42% loin). The perce ntage of PSE after evaluating through colour (< one percent) only corr elates in three percent with the pH- and in 6.9% with LF-measurement r esults. All in all it can be stated that the measurement of conductivi ty 40 minutes p.m. or of colour on the slaughterline are of no value f or the categorization of meat quality. The carcass weight is from 0.7 to 2.5 kg higher (depending on parameteres used) in the PSE-quality cl ass compared to the quality class of normal meat. The percentage of le an meat in the PSE-quality classes lies an average of 2.5% higher than in so called normal quality classes. With regard to the meat quality of the EUROP-classes it becomes clear that the percentage of PSE in cl ass E (highest class) is almost double as high as in the other classes . Thus paying the carcass only depending on weight and lean meat perce ntage is inadequate. The preliminary factors of strain which have a ne gative effect on meat quality are long duration of transport, high loa ding density and high humidity factor: The pH in loin and ham of pigs which are transported longer than two hours is as an average 0.04 to 0 .07 lower than the pH of pigs which were not transported as long. The higher the loading density is the lower the pH and on the other side t he higher the LF turned out to be. Pigs who have lower quality meat cl assified on hand of pH and LF are admitted an average of 0.02 to 0.06 qm/100 kg less room while being transported to the slaughterhouse. The humidity factor is an average of 2.4 (pH) and 5.1 (LF) higher in pigs classified to be lower quality with help of pH and LF than in normal quality pig-carcasses. Considering to this research differences in mea t quality are to be found between the different days of measurement (o n various days more than 50% of the results lie in the 'suspected to b e PSE'-area) as well as between the different farms of Origin and supp liers. A presentation of pH refering to the suppliers of animals can g ive a valuable hint to whether quality abating influences lie within t he origin or whether they are to be found with the carrier or the slau ghterhouse. When examinating this all, preliminary factors of strain a re to be put into relation.