I thought that heating uncooked food at a temperature above 135 degrees F for a relatively short amount of time and then keeping it cold right after was the only way to prevent food from making you sick, but I don’t understand how people can cook “low and slow” stews or crockpot food that’s been cooking for like 8+ hours and eat them without any problem.
In: 0
Bacteria and other pathogens start to die at around the temperature you said (135°F) and even a bit below that actually. If you hold food at that temperature for long enough, you will kill off nearly all bacteria that are there (you never kill of 100% but it’s enough to kill 99.9999% or something like that) and the food will be safe to eat. Holding food at a temperature that high (or higher) for longer will only make it **safer**, not less safe.
Temperatures between 40-140°F are usually referred to as the “danger zone”, where pathogens can grow. Now, I just told you pathogens actually start to die at temperatures as low as 135°F. So what gives? Well, what I said is true, but it does require that you are able to control the temperature reliably enough that it won’t dip to, say, 120°F for long periods of time. Official recommendations don’t want to skirt to close to the edge of what’s safe, so they build in a margin of error and put the boundary at 140°F.
Similarly, official recommendations often tell you to heat meat to an internal temperature of 160°F in order to render it safe for eating. Again, that’s to be extra safe, because at that temperature, pathogens are killed off (to safe levels) pretty much instantly. At lower temperatures, like 135°F, it takes longer to reduce the amount of pathogens to a safe level, so it takes more effort, control and precision. It’s also worth noting that lots of foods are habitually cooked to lower internal temps without serious consequences. If you like a medium-rare steak, that steak’s core internal temp hasn’t gone above 135°F (or thereabouts). and if cooked traditionally, it wasn’t held at that temperature for more than a few minutes. So it’s not guaranteed to be safe. However, beef is unlikely to contain parasites, and bacteria don’t tend to penetrate into an intact muscle of beef, staying mainly on the surface. All of which means that you can eat a medium-rare steak with minimal risk of food-borne illness.
Low-and-slow cooking techniques actually typically don’t skirt close to the danger zone anyway, unless you’re talking about something like sous vide cooking. The cooking temperatures are usually well in excess of 160°F, at which point all pathogens are destroyed anyway. Holding food at these temperatures will only pasteurize it further, so regular slow-cooking is actually an incredibly safe way to prepare food, as long as you do it right. (There is a slight risk that e.g. your slow-cooker develops a fault mid-way through the cooking process and then the food hangs out at unsafe temperatures for hours. Although, if the food had already been held at instant-pasteurization temperatures for hours before that, it will likely still be fine as long as you don’t wait too long before eating it.)
Latest Answers