Viability of Trichinella spiralis in traditional sour pork fermentation and its inactivation by microwave heating: Implications for zoonotic risk and food safety.

Abstract

Background and aim: Cultural dietary practices involving the consumption of raw or undercooked meat, such as traditional sour fermented pork, pose significant risks for foodborne parasitic infections, particularly trichinellosis caused by Trichinella spiralis. This study aimed to evaluate the viability of T. spiralis larvae during sour pork fermentation and to assess the efficacy of microwave heating as a practical method for inactivating the larvae.

Materials and methods: Laboratory-bred hamsters were experimentally infected with T. spiralis to obtain encysted muscle larvae. Infected muscle samples were incorporated into a traditional sour pork recipe and fermented at ambient temperature (28-30°C) for 5 days. Larval viability was assessed daily using propidium iodide staining and confocal microscopy. In a separate experiment, pork slices embedded with infected muscle were subjected to microwave heating at 400 W (1-4 min) and 800 W (0.5-4.5 min). Post-treatment viability was determined similarly.

Results: Encysted larvae remained viable throughout the 5-day fermentation period, with no uptake of propidium iodide observed in any samples. In contrast, microwave heating at 400 W for 3 min or at 800 W for 1 min or longer resulted in complete larval inactivation, as evidenced by positive staining. Non-heated controls retained viable larvae, while boiling served as an effective positive control for inactivation.

Conclusion: Traditional sour pork fermentation does not inactivate T. spiralis larvae within 5 days, underscoring a persistent zoonotic risk. However, microwave heating offers a rapid and accessible intervention for larval inactivation. These findings underscore the significance of public health education and food safety protocols in regions where the consumption of raw meat is culturally prevalent.