The effect of temperature and time on the viability of Taenia solium metacestodes in pork.

OBJECTIVE

Taenia solium taeniosis is a growing health problem in large parts of the world including Sub-Saharan Africa. Humans are infected by eating undercooked pork with T. solium metacestodes, which cause taeniosis. The aim of the present study was to assess the effect of increasing temperatures on T. solium metacestode viability in pork.

METHODS

Heavily T. solium infected pieces of pork were cooked in a water-bath at five different temperatures (40 °C, 50 °C, 60 °C, 70 °C and 80 °C) for 10-60 min. At each temperature/time point, five 5x5x5 cm pieces of pork fitted with thermometers at the core were placed in the water-bath. Controls were kept at 5 °C throughout exposure. After exposure, approximately 100 intact metacestodes were harvested and after a maximum of 6 h incubation at 37 °C in a culture media consisting of 50% porcine bile and 50% saline, the metacestodes were evaluated for viability.

RESULTS

The metacestodes were fully viable after cooking at a core temperature of 40 °C for up to an hour. The metacestodes were non-viable after cooking for >40 min at a core temperature over 50 °C. All metacestodes were dead after cooking for 30 min at a core temperature of 60 °C; at 70 °C, non-viability was found after 20 min and all metacestodes were dead after 10 min cooking at 80 °C.

CONCLUSION

Findings showed that pork pieces cooked at >80 °C for >10 min proved safe for human consumption. This means that dishes consisting of pork pieces in sizes not greater than a 5 cm cube which are immersed in continuously boiling water for at least 10 min would be safe to eat. However, pork deep-fried in oil may entail a risk due to generally shorter cooking time. More research on the cooking practises is needed in order to produce safe guidelines for risk-free pork consumption.