I was re-reading Dawn's post about the worst pork chops ever (19594) and did a search on the subject (trichinae internal temperature killed) on Google. Pork needs to be heated to certain temperatures and held there till ALL the meat is that temperature to kill trichinae.
This is pretty dense reading about trichinae in pork but below is a quote from this paper available at the link below. Notice the short time that pork has to be held at 140ºF to kill trichinae, and again remember that the meat has to be evenly heated to that temperature to kill it. This temp is not very high compared to what a lot of recipes recommend (which is in the virtual shoe leather realm, but I can understand the concerns)
Cooking - Commercial preparation of pork products by cooking requires that meat be heated to internal temperatures which have been shown to inactivate trichinae. For example, Trichinella spiralis is killed in 47 minutes at 52° C (125.6° F), in 6 minutes at 55° C (131° F), and in < 1 minute at
60° C (140° F). It should be noted that these times and temperatures apply only when the product reaches and maintains temperatures evenly distributed throughout the meat. Alternative methods of heating, particularly the use of microwaves, have been shown to give different results, with parasites not completely inactivated when product was heated to reach a prescribed end-point temperature. The U.S. Code of Federal Regulations for processed pork products reflects experimental data, and requires pork to be cooked for 2 hours at 52.2° C (126° F), for 15 minutes at 55.6° C (132° F), and for 1 minute at 60° C (140° F).
The U.S. Department of Agriculture recommends that consumers of fresh pork cook the product to an internal temperature of 71° C or 160° F. Although this is considerably higher than temperatures at which trichinae are killed (about 55° C or 131° F), it allows for different methods of cooking which do not always result in even distribution of temperature throughout the meat. It should be noted that heating to 77° C (171° F) or 82° C (180° F) was not completely effective when cooking was performed using microwaves.
Freezing - Experiments have been performed to determine the effect of cold temperatures on the survival of T. spiralis in pork. Predicted times required to kill trichinae were 8 minutes at -20° C (-4° F), 64 minutes at -15° C (5° F), and 4 days at -10° C (14° F). Trichinae were killed instantaneously at -23.3° C (-10° F). The U.S. Department of Agriculture's Code of Federal Regulations, requires that pork intended for use in processed products be frozen at -17.8° C (0° F) for 106 hours, at -20.6° C (-5° F) for 82 hours, at -23.3° C (-10° F) for 63 hours, at -26.1° C
(-15° F) for 48 hours, at -28.9° C (-20° F) for 35 hours, at -31.7° C (-25° F) for 22 hours, at
-34.5° C (-30° F) for 8 hours, and at -37.2° C (-35° F) for 0.5 hours. These extended times take into account the amount of time required for temperature to equalize within the meat along with a margin of safety.
http://www.aphis.usda.gov/vs/trichinae/docs/fact_sheet.htm
This is pretty dense reading about trichinae in pork but below is a quote from this paper available at the link below. Notice the short time that pork has to be held at 140ºF to kill trichinae, and again remember that the meat has to be evenly heated to that temperature to kill it. This temp is not very high compared to what a lot of recipes recommend (which is in the virtual shoe leather realm, but I can understand the concerns)
Cooking - Commercial preparation of pork products by cooking requires that meat be heated to internal temperatures which have been shown to inactivate trichinae. For example, Trichinella spiralis is killed in 47 minutes at 52° C (125.6° F), in 6 minutes at 55° C (131° F), and in < 1 minute at
60° C (140° F). It should be noted that these times and temperatures apply only when the product reaches and maintains temperatures evenly distributed throughout the meat. Alternative methods of heating, particularly the use of microwaves, have been shown to give different results, with parasites not completely inactivated when product was heated to reach a prescribed end-point temperature. The U.S. Code of Federal Regulations for processed pork products reflects experimental data, and requires pork to be cooked for 2 hours at 52.2° C (126° F), for 15 minutes at 55.6° C (132° F), and for 1 minute at 60° C (140° F).
The U.S. Department of Agriculture recommends that consumers of fresh pork cook the product to an internal temperature of 71° C or 160° F. Although this is considerably higher than temperatures at which trichinae are killed (about 55° C or 131° F), it allows for different methods of cooking which do not always result in even distribution of temperature throughout the meat. It should be noted that heating to 77° C (171° F) or 82° C (180° F) was not completely effective when cooking was performed using microwaves.
Freezing - Experiments have been performed to determine the effect of cold temperatures on the survival of T. spiralis in pork. Predicted times required to kill trichinae were 8 minutes at -20° C (-4° F), 64 minutes at -15° C (5° F), and 4 days at -10° C (14° F). Trichinae were killed instantaneously at -23.3° C (-10° F). The U.S. Department of Agriculture's Code of Federal Regulations, requires that pork intended for use in processed products be frozen at -17.8° C (0° F) for 106 hours, at -20.6° C (-5° F) for 82 hours, at -23.3° C (-10° F) for 63 hours, at -26.1° C
(-15° F) for 48 hours, at -28.9° C (-20° F) for 35 hours, at -31.7° C (-25° F) for 22 hours, at
-34.5° C (-30° F) for 8 hours, and at -37.2° C (-35° F) for 0.5 hours. These extended times take into account the amount of time required for temperature to equalize within the meat along with a margin of safety.
http://www.aphis.usda.gov/vs/trichinae/docs/fact_sheet.htm