Sous Vide Pasteurization Explained: Time and Temperature
By Dana Cole | Reviewed by Chef Daniel Pryce
Published · Last reviewed · 3 min read
Key takeaways
- Pasteurization is time plus temperature together, not just hitting a number, so a lower temperature needs a longer hold to be safe.
- Sous vide can pasteurize at temperatures well below a boil because the food holds at the target long enough to reduce pathogens to a safe level.
- Time to safety is set by thickness, not weight, because heat has to travel to the centre of the food.
- Avoid extended holds below about 130°F (54.4°C); those temperatures are for short cooks only, not long pasteurizing holds.
Sous vide pasteurization is making food safe by holding it at a precise temperature for a set time, so that temperature and time together reduce pathogens to a safe level rather than relying on a single high number. This is the part of sous vide that worried me most when I started, and once I understood it the water bath stopped feeling like a gamble. Here is how it actually works.
What pasteurization means here
Pasteurization is the reduction of pathogens to a safe level, and in sous vide it depends on time and temperature together, not just reaching a temperature. A hot pan makes a steak safe at the surface in seconds because it is searing far above any pathogen’s limit. A water bath works differently: it holds food at a steady, much lower temperature, such as 145 to 150°F (63 to 66°C) for chicken breast, and lets the hold do the work over time. The food cannot exceed the water temperature, so the only variables you control are the temperature you set and how long you keep it there. Our food-safety guide covers the wider rules; this article is about the time-and-temperature core.
Why lower temperatures need longer holds
Lower temperatures need longer holds because killing pathogens is a rate, not a switch. The hotter the food, the faster their numbers fall, so cooler food has to stay hot for longer to reach the same reduction. At about 165°F (74°C) the reduction is effectively instant, which is why instant-read charts quote it1. Drop to 145°F (63°C) and the same safety is reached, but it now takes a hold measured in many minutes to over an hour depending on thickness2. The first time I held a chicken breast at 146°F (63.3°C) for the full charted time, it came out pasteurized and far juicier than any 165°F (74°C) bird I had made, because the long hold replaced the high heat. This is the whole reason a pasteurization chart lists a time for every temperature instead of one magic number.
How thickness sets the time
Time to safety is set by thickness, not weight, because heat has to travel from the surface to the centre. A thick cut takes longer to come up to temperature and longer to pasteurize all the way through than a thin cut of the same weight. A piece around 1 inch (25 mm) reaches and holds safe far sooner than one at 2 inches (50 mm), and Baldwin’s tables are built around exactly this: you look up the thickness, not the mass2. I keep a small ruler by the bath and measure the thickest part of whatever I am cooking, because guessing here is guessing with safety. Food going in frozen needs roughly 50 percent more time to account for the extra heating.
Reading Baldwin’s tables
You read a pasteurization table by crossing your set temperature with your food’s thickness. Find the column for the temperature you have chosen, then the row for the measured thickness, and read off the time needed for a safe reduction of pathogens. Douglas Baldwin’s tables assume the food starts refrigerated and give the time both to heat the centre through and to pasteurize it, so the listed time is the full hold, not an extra on top2. The practical habit is simple: pick the temperature for the texture you want, measure thickness, look up the time, and do not pull the food early. Always match the chart to the specific food, since a chicken breast and a salmon fillet at the same thickness are not the same problem.
Where pasteurization stops working
Pasteurization stops being practical below about 130°F (54.4°C), so those temperatures are for short cooks only, never long holds. The danger zone is 40 to 140°F (4 to 60°C), the range where bacteria multiply, and temperatures under roughly 130°F (54.4°C) do not pasteurize in a sensible time, so holding food there for hours lets growth outrun any safety gain3. That is the line I do not cross for extended cooks. If you are cooking for someone who is pregnant, very young, elderly, or immunocompromised, skip the lower-temperature holds entirely and cook to standard safe internal temperatures, such as taking chicken breast to a fully safe result. Do not improvise the numbers; match a reputable chart and the guidance below.
This guide is general information and one cook’s experience, reviewed by a professional chef. Always follow current food-safety guidance for your situation, especially when cooking for higher-risk eaters.
Frequently asked questions
What is pasteurization in sous vide cooking?
Pasteurization is the reduction of pathogens to a safe level by holding food at a given temperature for a given time. In sous vide it matters because the water bath can hold food at a steady temperature far below a boil, such as 145°F (63°C), long enough to make it safe. The key idea is that safety comes from temperature and time together, not from reaching a number for a moment, so a lower temperature simply needs a longer hold.
Can you pasteurize chicken at 145°F (63°C)?
Yes, when you hold it there long enough for its thickness. Chicken breast cooked at about 145 to 150°F (63 to 66°C) becomes pasteurized and far juicier than chicken taken to the instant-safe 165°F (74°C), because the long hold does the work the high temperature would otherwise do in seconds. Use a thickness-based chart such as Douglas Baldwin's for the exact hold, and see our chicken breast guide.
Why do lower temperatures need longer times?
Because killing pathogens is a rate process: the hotter the food, the faster their numbers fall, so cooler food needs more time to reach the same reduction. At 165°F (74°C) the reduction is near instant; at 145°F (63°C) it takes time measured in many minutes to over an hour depending on thickness. This is why pasteurization charts list a time for every temperature rather than a single safe number.
Does thickness or weight decide the time?
Thickness, not weight. Heat travels from the surface to the centre, so a thick piece takes longer to come up to temperature and longer to pasteurize all the way through than a thin one of the same weight. Baldwin's tables are organised by thickness for exactly this reason. Measure the thickest part of the food, not how heavy it is, and add roughly 50 percent more time if it goes in frozen.
Is sous vide below 130°F (54.4°C) safe?
Only for short cooks, not for long holds. The danger zone is 40 to 140°F (4 to 60°C), and temperatures below about 130°F (54.4°C) do not pasteurize in a sensible time, so holding food there for hours lets bacteria grow. Keep those low temperatures to short cooks, and if you are serving people who are pregnant, very young, elderly, or immunocompromised, cook to standard safe internal temperatures instead.
How do I read a sous vide pasteurization table?
Find the column for your set temperature, then the row for the thickness of your food, and read off the time needed for a safe reduction of pathogens. Baldwin's tables assume the food starts refrigerated and give the time to both heat through and pasteurize. Always match the chart to the specific food and thickness rather than guessing, and confirm against USDA or FDA guidance.
References
- Safe Minimum Internal Temperature Chart, USDA Food Safety and Inspection Service. ↩
- A Practical Guide to Sous Vide Cooking: Pasteurization, Douglas Baldwin. ↩
- Cooking to Address Food Safety Concerns (Time and Temperature), U.S. Food and Drug Administration. ↩
Written by Dana Cole. Reviewed by Chef Daniel Pryce.
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