Survival of Trichinella spiralis in raw sausage production

Experimental studies were carried out on survival of T. spiralis in raw sau sage (Mettwurst) in dependence on the period of storage. For this purpose, raw sausage was produced from fresh pork contaminated with muscle larvae, L arval density in sausage was determined by the artificial digestion from th e 1st to 15th day of storage. Then, vitality of isolated larvae was examine d in vitro (cultivation in Dulbecco medium) and results were compared with those of in vivo examination (experimental infection of guinea pigs). Larva l density in raw sausage continuously decreased from the 1st to 7th day of storage with 228 and 58 larvae per gram, respectively and did not essential ly change from the 7th up to 15th day. Besides, vitality and infectivity of larvae which were isolated from raw sausage dropped with a longer storage time. According to the results of in vivo study in guinea pigs, larvae lost their infectivity if sausage was stored more than 8 days. Trichinella larvae will not efficiently be inactivated in raw sausage durin g processing and therefore, might be a risk for consumer. The risk of a foo d borne infection will decrease the longer the storage time of sausage rake s. Nevertheless, an efficient inactivation of larvae will be at a later sta ge of storage at which the sausage has normally been consumed.