I do my dehyrdrating in my oven, so my "
dehydrator experience" is with that device.
I have an old Thermador oven that has a convection mode which circulates air with a fan. The oven can be set as low as 140 degrees. That is low, but still high enough to kill pathogens but only if you keep it at that temperature for long enough. You have to look at the FDA's time vs. temp charts, which Dave has posted many times. I just looked at the chart he provided, and at 140 degrees, nine minutes is sufficient. When making jerky, it is in the oven for 4-10 hours, so the meat will be quite safe to eat. Also, the meat will spend almost no time in the danger zone because you slice it really thin, and each strip will very quickly get heated to the surrounding air temperature in minutes, not hours.
When I make jerky in my MES smoker, I set it to somewhere between 145 and 160, and let it smoke for at least 1.5 - 2.0 hours. I then move it into the convection oven to finish it because the air movement helps pull the moisture out more quickly.
The real issue, IMHO, with jerky safety is the moisture content, not the temperature (as long as you are heating to above 130 degrees). I didn't read the link that Dave provided, but I'm sure it talks about moisture content.
But the main reason for posting is to point out that if you own a convection oven, you may not need to purchase a
dehydrator.
[edit]
I did just read the link Dave provided, and find that it completely contradicts everything I've read on the FDA site about time vs. temperature and pathogens. I am confused, but my own conclusion is that the recommendations in that pamphlet are not to be taken too seriously. If what they say is true, then everyone doing sous vide cooking, where meat is held at 130-140 degrees for a few hours, without any exposure to any temperature higher than that, would be getting seriously ill.
That is not happening.
So, I think this is another case of providing unnecessary margins of safety because at super high temperatures, pathogens are killed instantly and therefore no one will ever have a problem. Of course if you follow these rules for other food, you'll end up with a dry chicken breast because the temperature at which pathogens are instantaneously killed is 165 degrees. If you instead cook that same breast via sous vide at 142 degrees for a few hours, you'll end up with the tastiest chicken breast you've ever had, and it will be perfectly safe.
So I think the same thing is true for jerky as for chicken and the recommendation to put your jerky strips on a cookie sheet in an oven for 275 for ten minutes, that will significantly alter (and not for the better) the result you get, and for what appears to be a bogus reason.
As is always true in life, it comes down to "who do you trust?" I am getting more and more skeptical of "studies," and this is especially true of things done at universities by graduate students. While I don't always trust the government, the FDA guidelines and rules are done by people with decades of experience, not some graduate student writing a research paper in order to get publication credit.
But I'm a grumpy old man, so who knows ...