[Effect of temperature on the viability of Trichinella spiralis larvae]

The aim of this work was to study the effect of temperature on the viability of free and encysted larvae of Trichinella spiralis from southwest Buenos Aires province, Argentina. Larvae were treated at variable temperatures (-30 °C, -20 °C, 4 °C, 20 °C, gradual heating between 0-100 °C). The time necessary to kill 100 % of larvae was calculated. During the first days of freezing, larval mortality significantly increased as a function of time. Regardless of temperature, encysted larvae survived longer than the free ones. At -30 °C, -20 °C, and 20 °C there were no significant differences between the survival curves for each larval stage. At 4 °C, mortality was less severe for encysted larvae. All free and encysted larvae died at 61 days and 95 days (-30 °C), 160 days and 180 days (-20 °C), 280 days and 330 days (4 °C) and 460 days and 590 days (20 °C), respectively. Cooking at 90 °C and 100 °C during 15 minutes killed 100 % of free and encysted larvae, respectively. Our results suggest that temperatures and exposure times traditionally used to treat meat products with a potential to transmit T. spiralis are not entirely efficient.