Factors affecting the efficiency of pooled sample digestion for the recovery of Trichinella spiralis from muscle tissue

Inspection for Trichinella spiralis in pork, horse and game meats is an important part of veterinary public health programmes in many countries. Variations of the pooled sample digestion test are the most widely used methods of inspection for this parasite. In this study, several aspects of the test, including sample preparation, reagent concentration and sample processing were examined for effect on test efficiency. Current methods using sample blending were equivalent or superior to sample grinding. Increasing the concentration of pepsin improved overall digestion slightly. The most critical factor affecting parasite recovery was sieve size. Currently used methods that employ a #80 (180 μm mesh) sieve limit the recovery of motile or dead parasites and therefore might decrease test sensitivity. It is recommended that a #45 (355 μm mesh) sieve be used to ensure optimal recovery of larvae.