Different meat handling methods can kill the larvae of Trichinella species and thereby prevent spread of trichinosis to humans. Failure to follow these practices can result in human trichinosis.
Several factors may affect the effectiveness of a set of conditions in larval inactivation. A temperature must be achieved throughout the meat, which takes longer with larger pieces. Most government regulations involve the addition of a considerable safety margin.
Cooking
Trichinella spiralis larvae may be killed:
(1) in 47 minutes at 52°C
(2) in 6 minutes at 55°C
(3) in less than 1 minute at 60°C
US Department of Agriculture Code of Federal Regulation times
Temperature |
Time Required |
52.2°C |
2 hours |
55.6°C |
15 minutes |
60°C |
1 minute |
A meat thermometer should be used to document internal temperatures achieved.
Microwave cooking may not give even heating throughout the meat and may be ineffective alone in larval inactivation unless longer times are used.
Freezing
Trichinella spiralis larvea may be killed:
(1) immediately at -23.3°C
(2) in 8 minutes at -20°C
(3) in 64 minutes at -15°C
(4) in 4 days at -10°C
US Department of Agriculture Code of Federal Regulation times
Temperature |
Time Required |
-17.8°C |
106 hours |
-20.6°C |
82 hours |
-23.3°C |
63 hours |
-26.1°C |
48 hours |
-28.9°C |
35 hours |
-31.7°C |
22 hours |
-34.5°C |
8 hours |
-37.2 |
0.5 hours |
time required in hours =
= (0.12878 * ((temperature in °C)^2) + (12.42 * (temperature in °C)) + 284.596
Trichinella nativa is a species that may remain viable after freezing for months or years. This may be a problem for preparation of wild game.
Other Methods
Smoking, salting and curing:
(1) Techniques vary in effectiveness to inactivate larvae.
(2) Some methods may fail to inactivate larvae.
(3) Practices must conform with published regulations (US Department of Agriculture, Code of Federal Regulations, Title 9, Chapter III, 318.10.
Irradiation: >= 30 krad Cesium 137 or other high energy X-ray source will inactivate larvae
Specialty: Infectious Diseases