Factors influencing the 18O/16O-ratio in meat juices

With respect to the question of whether the O-18/O-16-ratio of meat water could be used for meat origin analysis, factors influencing its delta(18)O-value have been examined. The O-18/O-16-ratio of meat water differs geographically, similar to known differences in precipitation and ground water. In Great Britain higher enrichments in O-18 were found in southern samples and in Germany in northern samples. However, it was not possible to distinguish between British and German beef: their O-18/O-16-ratios overlapped. British bovine samples the variation range of delta 18 O-values was 2.8 parts per thousand; in porcine samples it was 2.0 parts per thousand. British meat liquids from beef were enriched in O-18 by 1.3 +/- 0.3 parts per thousand compared with pork. In porcine samples of litter mates with identical breeding and age at slaughter, the range in the delta(18)O-values among individuals was 2.4 parts per thousand. Experiments revealed significant influences of the meat's storage and handling conditions on the O-18/O-16-ratio. After 10 h at 21.5 or 18.5 degreesC the delta(18)O-value increased by 0.4 or 0.3 parts per thousand per h, respectively, in samples (50 g) of chopped meat. The observed magnitude of changes might compensate for the geographical and seasonal differences. A precise origin assignment of the affected specimen on the base of delta(18)O-values of meat water is hence bound to be impossible.