By Dylan Clay
Contrary to popular belief, all beef jerky you buy in a store is cooked in some capacity.
Meaning, the beef jerky reaches an internal temperature at which the pathogens reach necessary log reductions to be deemed safe for consumption (concept explained below).
Beef jerky that’s sold commercially must undergo a lethality heat treatment before it is dehydrated.
The USDA/FSIS has strict guidelines for the sale of beef jerky – that documentation is also pretty hard to digest as a home jerky maker.
From Appendix A, page 10 discusses lethality.
Specifically they note:
“Lethality treatments achieve a specific reduction in the number of Salmonella and other pathogens in the product (i.e., an “X-Log10 colony forming units per gram1 (CFU/g)” reduction).”
FSIS, Appendix A, Pg 10.
Going back to the Jerky Guidelines document:
“For meat jerky, use of the product time-temperature combinations provided in Appendix A, including those temperatures above 158°F in which the time for the desired lethality is instantaneous, should help to ensure the safety of the product.”
FSIS, Compliance Guideline for Meat and Poultry Jerky, Pg. 18
Meaning, by pre-heating beef jerky to 158F, we achieve the desired lethality instantaneously.
To quote the USDA’s website:
“The USDA Meat and Poultry Hotline’s current recommendation for making jerky safely is to heat meat to 160 °F and poultry to 165 °F before the dehydrating process. This step assures that any bacteria present will be destroyed by wet heat.”
USDA.gov
In my opinion, the reason they state those temperatures is because they realize most Home Jerky makers can’t control for things like Relative Humidity in their oven, water activity level testing of their jerky (aside from visual queues), come-up-temperature (CUT), etc.
Rather, they can achieve internal temperatures easily via a kitchen oven that can be verified via a probe thermometer.
Meaning a blanket statement of 158F for beef is adequate.
In the world of beef jerky you’ll see reductions of harmful bacteria expressed in terms of “log reductions.”
Beef jerky specifically must achieve a 5.0 log reduction of Salmonella spp. – as well as 5.0 log reductions in other common harmful bacteria – namely E.Coli.
A “log-reduction” implies a 10-fold reduction of bacteria after every step.
Meaning, a “1-log” reduction would reduce the number of bacteria by 90% – leaving behind 100,000 microbes.
Most dehydrators will have a range of temperatures that go from ~86F to 165F.
I can tell you from personal experience that most won’t reach near an ambient temperature of 158F; Meaning, how can the meat ever reach 158F?
Again, this is likely why the USDA recommends a pre-heat treatment before dehydration.
The USDA also cites case studies where-in beef jerky was dehydrated at 145F for 10+ hours – pathogens like E.Coli were still present.
For some reason the lethality treatments above are a point of contention for a lot of people; Often the people who scoff at the above cite Water Activity as the most important factor, yet they also don’t measure that either.
At the end of the day, it’s up to you with regards to your own safety – especially if you’re immunocompromised.
I’ve made jerky both ways for over 15 years and there is quite literally no difference in taste/texture.
At home, pre-heat treatment for beef jerky is a relatively simple process and takes about 10 minutes.
To do so you will need:
1. Start by pre-heating your oven. I find that 350F works best for pre-heat treatment.
2. Once the oven is up to 350F, I take out my baking sheet and line it with aluminum foil. This is done to make clean-up easier and is totally optional.
3. Place your oven safe cooling racks on top of the baking sheet. This elevates the beef jerky off the baking sheet.
I’ve tested not using these cooling racks and what will happen is you’ll likely case-harden the meat.
Essentially the outside becomes “seared” or “hardened” which prevents the interior meat from drying out.
4. Place your beef jerky on the cooling racks.
I personally DO NOT pat dry my beef jerky. By patting your meat dry you’re taking away the potential for flavor.
If anything, this pre-heat treatment can function as your “pat dry” or “drip dry” as excess will drip onto the baking sheet.
5. When you initially slice your meat – you should leave a single piece thicker than the others. This way you can insert the probe into the meat to get an accurate reading.
If you didn’t have this forethought, simply find the thickest piece and probe it to the best of your ability.
6. Put the baking sheet in the oven and wait for the internal temperature of the thickest piece to reach 158F.
From documentation provided by the USDA (pg 35.) we can see that at 158F, the meat achieves a 7log reduction and instantaneously kills bacteria.
This process will typically take ~10 minutes in an oven at 350F.
7. Once the thickest piece reaches 158F, take the baking sheet out of the oven and then start placing your heat treated jerky in your dehydrator.
You then dehydrate the meat at around 130-140F (temperatures most commercial dehydrators can actually achieve).
