Controlled freezing inactivates Trichinella britovi in wild boar meat: Insights from a murine infection model and multiplex polymerase chain reaction.

Abstract

Background and aim: Trichinellosis remains a public health concern globally due to the zoonotic potential of consuming undercooked meat infected with Trichinella spp. larvae. Trichinella britovi, known for its moderate freeze tolerance, presents a food safety challenge, particularly in game meat such as wild boar. This study aimed to evaluate the infectivity of T. britovi larvae in wild boar meat subjected to prolonged freezing under controlled conditions.

Materials and methods: Muscle samples (50 g each) from a wild boar naturally infected with T. britovi were frozen for 56 days at four temperatures: -18°C, -20°C, -29°C, and -40°C. Post-thaw, larval viability was assessed through artificial digestion, and infectivity was tested in a murine model using BALB/c mice. Each experimental group (n = 5 mice) received 120 larvae through gavage over 2 days. After 56 days, mice were euthanized, and muscle tissues were examined histologically. Molecular confirmation was performed using multiplex polymerase chain reaction on formalin-fixed tissues.

Results: Despite larval motility post-thaw, no viable T. britovi DNA was detected in the muscle tissues of infected mice. Histological examination showed structures resembling Trichinella cysts in all experimental groups, but these were not molecularly confirmed. The control group remained negative throughout.

Conclusion: Controlled freezing at temperatures as low as -18°C for 8 weeks rendered T. britovi larvae in wild boar meat non-infectious in a murine model. These findings suggest that freezing may be a viable strategy for reducing the risk of trichinellosis transmission through game meat. However, given species-specific variability and environmental influences, further studies across diverse conditions are warranted to refine food safety protocols.