The parasite was discovered in the 19^th century and is predominantly associated with pork products since the pig is the most common domesticated animal used for food that is known to carry this worm.

Wild game such as rodents, skunk, raccoons, foxes, boar, cougar and bear as well as horse can be carriers.  Cougar jerky in the southwestern United States caused the last large outbreak of this disease in the U.S. in 1998.  Horsemeat has been associated with outbreaks in Europe as eating horse is more common there.  The pork industry is trying to improve the reputation of pork in the U.S. as the incidence of Trichinellosis has been greatly reduced in recent years.

In 1943 the National Institute of Health reported that 16.1% of the United States population was infected with this intestinal disease.  By 1970 the rate had declined to 4.2% and it has declined much further since.   One of the reasons is that pigs are no longer fed the raw intestines from slaughtered hogs.  They are often grain fed.  In fact the major source of Trichinellosis in the U.S. today, and it may well be the only source, is wild game.

Even if the tapeworm infects meat, cooking and storage procedures will kill it.  The Roundworm Trichenella Spiralis is killed at cooking temperatures of greater than 140 degrees Fahrenheit.  Since thermometers can be inaccurate experts recommend cooking temperatures greater then 150 degrees F.  Do not eat rare pork.  In the past recommendations were to cook fresh pork to temperatures greater then 170 degrees F rendering the fresh meat to the texture of shoe leather.  This may have been a bit of an over-kill.

Trichinella is also destroyed if it is frozen to less then –5 degrees F for greater then 25 days or less the – 22 degrees F for greater than 25 hours.  The rise in the home freezer may also play a role in the decline in this disease.  Ordinary curing and smoking procedures do not kill this tapeworm and this is what caused the outbreak of the cougar jerky.

Since all meat and meat products contain a certain amount of contamination it is actually unwise to undercook any meat or meat product.   The bottom line may be to use an accurate thermometer, and cook frozen pork that has been frozen to 150 degrees Fahrenheit.  Fresh pork tenderloin is both lean and nutritious.