I have been interested in sous vide and low temperature cooking lately. However I have been a bit wary of some of the temperatures they cook at as far as food safety goes. One example is Heston Blumenthal's roast chicken. He does it low and slow until the internal temperature reaches 140F. However current FDA recommendations say it should be cooked to 165F. As much as I want my food to taste good I also want to be safe. So I did some research. I found this PDF which summarizes things pretty well.
It turns that it's not just temperature but also time. The standard for chicken is a 7D reduction in bacteria. This basically means the bacteria population is reduced by 99.99999% of the original population. At 165F this is attained instantaneously which is the reason the FDA chooses that temp. However the same standard can be reached by holding it at lower temperatures for a longer amount of time. According to one of the charts on the PDF you can attain this at 140F by holding it there for ~35 minutes. Since Heston cooks this for several hours, he easily meets the time requirement and the chicken is more then safe without drying out the meat. At higher temperature you can shorten the time and you can even go as low as 135F and still kill bacteria although it might be a little too rare for some people. This also means that items that are cooked sous vide for 24 hours easily meet this time requirement as well.
So my argument is that while it's better to be safe then sorry, you should also be rational in your fears. To me cooking at 165F is like walking with a helmet on. You are definitely safer with the helmet but you are also perfectly fine without it. Am I wrong in my thinking?