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If there's one thing you need to know when cooking, whether it is using sous vide or any other technique, it is what procedures are important for you follow to be safe when preparing your food. I've put together a list of the top safety points in regards to sous vide. If you follow them, you won't get sick according to the US Government, Harold McGee, Douglas Baldwin, and Serious Eats, whose more scientific-based leads I follow.
Note: If you prefer, you can jump right to the Lesson Recap.
Before I start though, I think it's important to point out that sous vide is no more or less safe than other methods of cooking. There's a lot of talk about the safety of sous vide, but it's just as easy to make yourself sick by under-cooking a chicken in the oven, or not pasteurizing grilled pork. So don't be intimidated, once you know a few rules of thumb you will be all set
From a safety standpoint, food cooking at temperatures below 130°F (54.4°C) isn't cooking at all, it's just being warmed. The bacteria we are trying to remove from cooking thrive from around 40°F (4.4°C) to 126°F (52.2°C), and they stop growing but don't start dying quickly until around 130°F (54.4°C). That range is known as the "danger zone" (cue Top Gun music) and it's often referred to in food safety circles.
Note that sometimes the danger zone is even considered to be up to 140°F (60°C) but that is based on building in a margin of error for restaurants, not the actual growth and death of the pathogens.
Cooking a piece of meat below 130°F (54.4°C) is the equivalent to letting it sit on your counter. It's fine for a few hours but it's not something you'll want to do all day. A generally accepted safe overall time in the danger zone, from leaving the fridge through cooking and eating is generally considered 3 to 4 hours.
Any piece of food that needs cooked longer than a few hours should be cooked at a minimum temperature of 130°F (54.4°C). If there is only one thing to remember about cooking in general, and sous vide cooking specifically, it's to not have your food between 40°F (4.4°C) and 130°F (54.4°C) for more than a few hours.
Note: For a really good look at this process, as well as many other scientific underpinnings of cooking, I highly recommend On Food and Cooking by Harold McGee.
Most sous vide circulators are very precise and the temperature does not fluctuate much at all. However, they can sometimes become uncalibrated and heat to the wrong temperature, usually only by a degree or two.
If you push the limits of the danger zone, that degree could be the difference between safe food and unsafe food.
Because of this potential calibration issue, it's good to double check the temperature of your circulator every few weeks with another thermometer. I also recommend cooking a degree or two above the danger zone for all cooks over a few hours unless you have just calibrated your machine. If you must push the danger zone, I highly suggest getting a second thermometer that you can use to double check the temperature of the water.
Sometimes when cooking you want to ensure your food is pasteurized, not just heated through. This is particularly important for chicken and poultry, blade-tenderized steaks, and low quality fish.
Warning Note: It is very important to always pasteurized food when you are serving it to immuno-compromised people. This generally includes pregnant women, the elderly, babies, or those with weak immune systems.
Pasteurization occurs when the food is held at a specific temperature for a certain amount of time. The higher the temperature is, the faster the food is pasteurized. Even though the temperatures in the chart below range from barely medium-rare to medium-well they are all equally safe to eat when cooked for the indicated times.
These times all start once the middle of the piece of meat has reached the indicated temperature. I will talk more about cooking by thickness in the next lesson, but for now you can use my thickness ruler to determine how long it takes to reach the indicated temperature.
In the past the "recommended cooking times" that the US Government put out were designed to produced pasteurized food instantly. For example, at the generally recommended chicken temperature of 165°F (73.8°C) it will be pasteurized in less than a second. That short amount of time is why the government recommends it, so if a cook pulls a piece of chicken off the grill right as it hits the temperature, it'll still be safe to eat. But chicken cooked to 165°F (73.8°C) and held for one second, is just as safe as chicken cooked to 140°F (60.0°C) and held for 30 minutes.
Showcase Recipe: For a good example of chicken pasteurization, you can look at my Sous Vide Chicken Recipe with Bulgar Salad and Za'atar Onions. It discusses the pasteurization times for chicken and general cooking times.
A main concern of sous vide safety is cooking in plastic and whether or not this is a dangerous practice. Many scientists and chefs believe that cooking in food-safe, BPA-free plastic at these low temperatures does not pose any risk, the temperature is about equivalent to leaving a bottle of water in your car, or in a semi-truck during transport in summer. This included Ziploc freezer bags, sous vide bags, and most food-safe plastics.
However, I find it hard to believe that we know everything about how plastic reacts to heat, water, our bodies, and the environment. As such, I encourage you to read up on the safety of plastic in sous vide and plastic in general and come to your own conclusions about the safety of using these techniques.
I hope this will at least give you some various perspectives on it and you can make an informed opinion of your own!
In this lesson we discussed the four key pieces of safety information to keep in mind when cooking with sous vide. They were:
If you keep those key points in mind, you shouldn't have any health issues related to sous vide, or other methods of cooking!
I also shared some key links with you, namely
Do you know anyone that is struggling with sous vide and would find this information helpful? Why not do them a favor and send them a link to this Exploring Sous Vide email course or get them a printed version of this course!
Thanks again and happy cooking!
Jason Logsdon, Amazing Food Made Easy