Early post-mortem discrimination of water-holding capacity in pig longissimus muscle using new ultrasound method

Newly developed ultrasound equipment was tested for on-line determination of water-holding capacity (WHC) early post mortem (p.m.). The experiment was based on measurements of m. longissimus dorsi (LD) from 10 pigs, five of which were treated to result in pork with high WHC and five to result in pork with low WHC. Ultrasound measurements were carried out on the carcass of each pig every ten minutes from 15 to 85 min p.m. at three locations of the LD. Low field nuclear magnetic resonance (NMR) measurements were performed on excised samples simultaneously with the ultrasound measurements and at 24 h p.m. Drip loss was measured by Honikel's bag method. The ultrasound experiment demonstrated that classification of meat with high and low WHC was possible, but only at 85 min p.m., and only by the measurements obtained at the posterior end of the LD. NMR measurements underlined that there are structural differences in meat influenced by pre-slaughter treatment prior to 85 min p.m. However, meat properties that determine WHC were apparently not expressed sufficiently to be registered by the applied pragmatic handheld ultrasound equipment before 85 min p.m.