K Kruger
Senior Cook
(AKA trichina or trichinae)
A couple or three decades ago when many of us in the restaurant biz became aware of the possibility for lower finish internals in pork, 137F became the new number. As commercial pork had been getting increasingly (and unfortunately) leaner over the years, many chefs had all but abandoned bothering with simply preparing loins and tenderloins, instead using more labor- or time-intensive approaches (like marinades) in an effort to maintain moisture. Lower finish internals (which emanated from research but with little further details) were adopted wholesale, and many chefs I knew at the time re-introduced or introduced menu items they'd pretty much given up on--I know I did.
Several weeks ago, while in a discussion about pork, game meats, Trich and Salmonella, it arose that the kill point for Trich, a parisitic worm, is just as much a time @ temp issue as exists for the bacteria that cause food-borne illnesses. (Duh! Of course! I felt like such an idiot.)
In other words, once a particular temp is reached it becomes a matter of time at that temp for the kill step to be completed. Higher temps require shorter times and the times become shorter still as temps increase, till such a temp when the time is so short as to be considered 'instant'. (This is the same for bacteria. See here and here for time/temp info for meats and poultry.)
A gentleman involved in the discussion pointed us to the Code of Federal Regulations (specifically, 9CFR318.10, pp 244-256, revised in January of last year) that includes a time @ temp chart. It is based on the research of Tony Kotula, et al., from the 80s. Here:
Minimum Internal Temp
F ...... C ...... Minimum Time
________________________________
120 ... 49 ... 21 hours
122 ... 50 ... 9.5 hours
124 ... 51.1 ... 4.5 hours
126 ... 52.2 ... 2 hours
128 ... 53.4 ... 1 hour
130 ... 54.5 ... 30 min
132 ... 55.6 ... 15 min
134 ... 56.7 ... 6 min
136 ... 57.8 ... 3 min
138 ... 58.9 ... 2 min
140 ... 60 ... 1 min
142 ... 61.1 ... 1 min
144 ... 62.2 ... Instant
******************************
You'll note there is no 137 (which would come in around 2.3 min). I'm guessing that back then 137 was selected because that was the lowest temp that, when considering the probable time factor (the amount of time between hitting 137 and actually cutting the meat) coupled with the natural increase in internal temp that occurs during this rest, more than amounted to the just over 2 minutes necessary.
I'll reiterate: The instances of Trich in commercial pork are vanishingly rare but should not be assumed to be non-existant. Also: Bimetal analog therms should NOT be used for food safety purposes in thin items. Use a thermocouple or thermistor digital. (I don't use them for items of any thickness. Up to you.) Also: The chart above is for use with commercial pork, not wild game meats. They are susceptible to strains of Trich which are more temp resistant.
A couple or three decades ago when many of us in the restaurant biz became aware of the possibility for lower finish internals in pork, 137F became the new number. As commercial pork had been getting increasingly (and unfortunately) leaner over the years, many chefs had all but abandoned bothering with simply preparing loins and tenderloins, instead using more labor- or time-intensive approaches (like marinades) in an effort to maintain moisture. Lower finish internals (which emanated from research but with little further details) were adopted wholesale, and many chefs I knew at the time re-introduced or introduced menu items they'd pretty much given up on--I know I did.
Several weeks ago, while in a discussion about pork, game meats, Trich and Salmonella, it arose that the kill point for Trich, a parisitic worm, is just as much a time @ temp issue as exists for the bacteria that cause food-borne illnesses. (Duh! Of course! I felt like such an idiot.)
In other words, once a particular temp is reached it becomes a matter of time at that temp for the kill step to be completed. Higher temps require shorter times and the times become shorter still as temps increase, till such a temp when the time is so short as to be considered 'instant'. (This is the same for bacteria. See here and here for time/temp info for meats and poultry.)
A gentleman involved in the discussion pointed us to the Code of Federal Regulations (specifically, 9CFR318.10, pp 244-256, revised in January of last year) that includes a time @ temp chart. It is based on the research of Tony Kotula, et al., from the 80s. Here:
Minimum Internal Temp
F ...... C ...... Minimum Time
________________________________
120 ... 49 ... 21 hours
122 ... 50 ... 9.5 hours
124 ... 51.1 ... 4.5 hours
126 ... 52.2 ... 2 hours
128 ... 53.4 ... 1 hour
130 ... 54.5 ... 30 min
132 ... 55.6 ... 15 min
134 ... 56.7 ... 6 min
136 ... 57.8 ... 3 min
138 ... 58.9 ... 2 min
140 ... 60 ... 1 min
142 ... 61.1 ... 1 min
144 ... 62.2 ... Instant
******************************
You'll note there is no 137 (which would come in around 2.3 min). I'm guessing that back then 137 was selected because that was the lowest temp that, when considering the probable time factor (the amount of time between hitting 137 and actually cutting the meat) coupled with the natural increase in internal temp that occurs during this rest, more than amounted to the just over 2 minutes necessary.
I'll reiterate: The instances of Trich in commercial pork are vanishingly rare but should not be assumed to be non-existant. Also: Bimetal analog therms should NOT be used for food safety purposes in thin items. Use a thermocouple or thermistor digital. (I don't use them for items of any thickness. Up to you.) Also: The chart above is for use with commercial pork, not wild game meats. They are susceptible to strains of Trich which are more temp resistant.