What's happens at temperatures in both the 'pasteurisation' and 'danger' zone? I am new to cooking and even newer to sous vide cooking. I have been trying to find as much information as I can with regards to cooking steak in the sous vide. One thing I am particularly confused by is certain temperatures in the 'danger' zone, between 40f-140f.
I have seen multiple youtube videos and articles stating not to go over a certain cooking time (usually 2.5h) in a sous vide when cooking under a certain temperature in the danger zone (usually 135f). The claim is for food safety reasons. However, I also found a document (by googling 'usda pasteurisation chart') for which it states that at 130f, for example, you can pasteurise or get a significant reduction in salmonella bacteria by cooking for about 2 hours.
I'm really confused by this as it seems to be that there are certain temperatures at which you can achieve 'pasteurisation', but which fall in the danger zone and so should apparently have way more bacteria and food safety concerns. Can anyone explain what's going on in these temperature ranges? Particularly in the 130f to 140f range where steaks are often sous vide?
I've read through this but I'm still not exactly clear on what's happening in this particular case Can I sous-vide meat (at a temperature between 40&#186;F and 140&#186;F) for more than four hours?.
Thank you!
What you need to understand is that making raw proteins safe for consumption is not simply a function of temperature.  It is a function of time plus temperature.  Because of the precise temperature control of sous vide, one can cook at lower temperatures IF one understands that a longer time at those temperatures renders food safe.  There is no better explanation than the work of Douglas Baldwin.  I would recommend reading that for starters.
Most food pathogens stop growing at 122F (50C).  However, clostridium perfringens can grow up to 126.1F (52.3C).  So, in general sous vide cooking is done above these temperatures.  However, there are exceptions to that.  You would likely not want to cook a steak at that temperature.