Gamma radiation effect on Trichinella spiralis and Trichinella pseudospiralis infected wild boar meat

PASQUALETTI, M; MONTALVO, F; BESSI, C; ARONOWICZ, T; FARIÑA, F; ERCOLE, M; RIBICICH, M.; ACERBO, M.

Cluj-Napoca

Conferencia; 15th International Conference on Trichinellosis; 2019

Irradiation as a method to destroy meat pathogens and to produce secure food for consumption was originally rejected by the consumers. The International Commission on Trichinellosis (ICT) considers an irradiation of 0.3 kGy effective to inactivate T. spiralis muscle larvae (L1). The present study aims to find the effect of irradiation in order to inactivate muscle larvae of T. spiralis and T. pseudospiralis in wild boars. Two animals were inoculated per os with 20000 L1 of T. spiralis and T. pseudospiralis, respectively. Both animals were euthanized 20 weeks post infection (wpi), 20 g of side ribs, boston butt and shoulder were used to determine the larvae burden and the reproductive capacity index (RCI). Besides, samples of 250 g of these muscles were obtained and vacuum packed for further treatment. The irradiation was undertaken at Atomic Centre of Ezeiza (CNEA ? Argentine National Commission of Atomic Energy) and measured with an alanine dosimeter with a minimum and maximum dose of 0.32 ? 0.41 kGy, respectively. After treatment, 20 g were cut from the centre of each muscle sample 24 h, 7, 14 and 21 days post-irradiation. All samples were individually processed by artificial digestion. CF1 mice (n=72) were inoculated with 300 L1 from the recovered larvae. Animals were euthanized 42 days pi and each carcase was digested. Moreover, three mice were inoculated with 600 L1 obtained from the previous irradiated and digested muscle samples in order to recover adult worms. After 72 hours post inoculation, animals were euthanized and the small intestine was removed. The intestine was longitudinally opened and cut in pieces of 5 cm long and placed in falcon tubes with 0.9 % NaCl saline solution to incubate for 5/12 h at 37ºC. Prior to the experiment, the RCI for T. spiralis and T. pseudospiralis was determined as 88.1 and 59.9, respectively. All larvae obtained post-irradiation showed integrity of the cuticle and active motility. No adult worms nor muscle larvae were found of T. spiralis or T. pseudospiralis in the infected mice with irradiated L1. The present results reinforces the importance of irradiation as a method to inactivate encapsulated and nonencapsulated Trichinella species. The present research was approved by the Committee for the Use and Care of Laboratory Animals (CICUAL) of the Facultad de Ciencias Veterinarias, University of Buenos Aires, under permit number 2018/22. This work was supported by Universidad de Buenos Aires, Secretaría de Ciencia y Técnica Subsidio UBACyT 20020130100336BA and UBACyT 220170200331BA and Ministerio de Ciencia y Tecnología, FONCyT Subsidio PICT-2015-2350 and PICT-2015-3469.