Sous Vide and the Danger Zone?

[checkerfred]

I've done a search here and on google but I'm still not getting how cooking with sous vide is safe. Specifically getting the food out of the danger zone in ample time. I can see if it's a thinner cut of meat, but what about something like a roast or butt? I see where people cook them for like 8-16 hours at temps of 140-150. How does a larger cut hit that internal temperature in time to be safe?

 

[Fgignac]

My understanding is that this comes down to 3 things.

First, when dealing with full muscles (like roast or butt) as opposed to ground meat (like burgers or sausage), there is very little change of there being harmful bacteria on the inside of the meat if it was properly handled. Most pathogens exist in the animal's digestive system an not inside the muscles. So unless the meat was prodded to the center, any bacteria would be on the surface. This is why it is safe to eat a rare cooked steak, as long as it was well handled by the butcher.

Second, water is a much better conductor of heat than air. This means that, in a water bath, the temperature of your roast will actually rise much faster than it would in a smoker or oven at the same temperature. So it's actually getting up to safe temp faster than you think. Minimum cooking time can be easily calculated with the thickness of the meat and the temperature of the water. If you do a google search for "sous vide cooking time chart" you will be able to find many tools to allow you to figure out the minimum time required to bring a piece up to temp. Anything longer than this (like doing to butt for 18 hours) is only about texture. The extended cooking time breaks down the connective tissue and make for a more tender end product. That is one the big advantages of sous-vide. By tweaking temperature and cooking time you can create exactly the texture you want.

Third, anything cooked over 130* for enough time will be pasteurized. Killing bacteria isn't just a matter of temp, it is a combination of time and temp. Bacteria start dying at 130*, but at a slow rate. The hotter it gets, the faster they die. So holding a piece of meat at 130* for long enough will be just as effective as heating it to 165*. This is also why it is not recommended to cook something lower than 130* for more than 2 hours. At this temperature, pasteurization does not take place and you are essentially "incubating" the bacteria. Again, search for "sous vide pasteurization chart" and you will find tools that will show you how long you need to keep various meats and a certain temperature to insure safety.

 

[daveomak]

http://www.douglasbaldwin.com/sous-vide.html

 

[checkerfred]

My understanding is that this comes down to 3 things.

First, when dealing with full muscles (like roast or butt) as opposed to ground meat (like burgers or sausage), there is very little change of there being harmful bacteria on the inside of the meat if it was properly handled. Most pathogens exist in the animal's digestive system an not inside the muscles. So unless the meat was prodded to the center, any bacteria would be on the surface. This is why it is safe to eat a rare cooked steak, as long as it was well handled by the butcher.

Second, water is a much better conductor of heat than air. This means that, in a water bath, the temperature of your roast will actually rise much faster than it would in a smoker or oven at the same temperature. So it's actually getting up to safe temp faster than you think. Minimum cooking time can be easily calculated with the thickness of the meat and the temperature of the water. If you do a google search for "sous vide cooking time chart" you will be able to find many tools to allow you to figure out the minimum time required to bring a piece up to temp. Anything longer than this (like doing to butt for 18 hours) is only about texture. The extended cooking time breaks down the connective tissue and make for a more tender end product. That is one the big advantages of sous-vide. By tweaking temperature and cooking time you can create exactly the texture you want.

Third, anything cooked over 130* for enough time will be pasteurized. Killing bacteria isn't just a matter of temp, it is a combination of time and temp. Bacteria start dying at 130*, but at a slow rate. The hotter it gets, the faster they die. So holding a piece of meat at 130* for long enough will be just as effective as heating it to 165*. This is also why it is not recommended to cook something lower than 130* for more than 2 hours. At this temperature, pasteurization does not take place and you are essentially "incubating" the bacteria. Again, search for "sous vide pasteurization chart" and you will find tools that will show you how long you need to keep various meats and a certain temperature to insure safety.

What about ground meat? I’ve seen people doing burgers sous vide style. I assume that since they aren’t super thick they come up to temp quick enough?

 

[checkerfred]

Thanks Dave!

 

[dr k]

http://www.douglasbaldwin.com/sous-vide.html

View attachment 387928

this is his heating table not pasteurizing table. Just checking to make sure you wanted the other.

 

[SonnyE]

If you might need a converter to figure out Inches to mm...
Try this.

 

[SonnyE]

I've done Pork Loin via Sous Vide, which is essentially a pork roast. (Don't pop my bubble.)
I did it at 145° F for 6, 8, and 12 hours. I haven't found my favorite time yet, because I keep futzing with seasonings and Olive oil, and generally experimenting.
But... they have come out good and I ate them. I think I like the 12 just fine.
Now, if anybody thinks 145° for 12 hours is going to leave anything to question, I suggest you stick your finger in 145° water for 12 hours, then tell me if any bacteria (or anything else) is still alive on your finger.
I'm quite sure the answer will be no.

 

[checkerfred]

this is his heating table not pasteurizing table. Just checking to make sure you wanted the other.

Good catch

 

[chef jimmyj]

Fgignac...Nailed it! Could not have given a better explanation myself. Like Point...JJ

 

[TomKnollRFV]

I think the other thing you need to remember is that <assuming you set up the Sous Vide right> it's immersed in the hot water. There should be no air, some people vaccum seal every thing for this, not just ziplock+force the air out. This means there is a submerged constant heating effect.

So the outside of the meat, where the bacteria likes to be, will be cooked fairly quickly. Also when doing steak etc, you do a reverse sear <or I'd like to think every one does> which will most definitely get the outside raised to a high enough temp in a hurry and will likely bring the interior temps up briefly and not toughen up the meat.

That said, I'm not sure I'd want to sous vide raw ground meat. That to me is the iffy zone <also I bet it would look really icky..>

 

[Fgignac]

What about ground meat? I’ve seen people doing burgers sous vide style. I assume that since they aren’t super thick they come up to temp quick enough?

With ground meat, the bacteria that is on the outside, obviously, gets mixed throughout the meat. I often do burgers and sausages sous-vide. But with ground meat I always cook to pasteurization. Properly pasteurized meat is generally just as safe as "well done" meat, even if the temperature is lower.

Fgignac...Nailed it! Could not have given a better explanation myself. Like Point...JJ

Thank you sir.

 

[daveomak]

Morning folks.... checkerfred had some concerns about the "danger zone".. So, I opted to list the "heating time" table so he could see just how long it took to get the meat temps up to safe/pasteurization temps...
I think I was just attempting to show how long it does take to heat up meats, in a water oven...

Fgignac pointed out 2 of the most important notes you can have in your cooking arsenal.... Whole muscle meats are sterile inside, until adulterated..... and ground meats are terribly contaminated and all methods at your disposal are good to use to keep it safe to eat..

I've done a search here and on google but I'm still not getting how cooking with sous vide is safe. Specifically getting the food out of the danger zone in ample time. I can see if it's a thinner cut of meat, but what about something like a roast or butt? I see where people cook them for like 8-16 hours at temps of 140-150. How does a larger cut hit that internal temperature in time to be safe?

 

[chef jimmyj]

Hamburgers and Sausage are sufficiently thin that they heat quickly enough to be risk free. I would not even consider the 4 pound meat loaves I make. I don't see the point anyway. My meat loaf is very tender. What is there to gain?...JJ

 

[SonnyE]

Hamburgers and Sausage are sufficiently thin that they heat quickly enough to be risk free. I would not even consider the 4 pound meat loaves I make. I don't see the point anyway. My meat loaf is very tender. What is there to gain?...JJ

Not sure JJ, but if you have something in a SV bath, couldn't you just leave it in there until the perpetually late get there and get settled (Glass of whine, Or Dervies, yackabit).
Sous Vide isn't for everything. For example, I think it would make a terrible Ice Cream maker.....

 

[Bearcarver]

I've done Pork Loin via Sous Vide, which is essentially a pork roast. (Don't pop my bubble.)
I did it at 145° F for 6, 8, and 12 hours. I haven't found my favorite time yet, because I keep futzing with seasonings and Olive oil, and generally experimenting.
But... they have come out good and I ate them. I think I like the 12 just fine.
Now, if anybody thinks 145° for 12 hours is going to leave anything to question, I suggest you stick your finger in 145° water for 12 hours, then tell me if any bacteria (or anything else) is still alive on your finger.
I'm quite sure the answer will be no.

Not a very good example of Sous Vide making meat safe.
Pork is safe at 145° IT no matter what the method of cooking is.
The amazing thing is when Pork is safe to eat after 136° for 3 1/2 hours in the Sous Vide.

Bear

 

[SonnyE]

Not a very good example of Sous Vide making meat safe.
Pork is safe at 145° IT no matter what the method of cooking is.
The amazing thing is when Pork is safe to eat after 136° for 3 1/2 hours in the Sous Vide.

Bear

Maybe not to you Bear, but delicious to me.

 

[chef jimmyj]

Once again the USDA temps are designed with a broad margin of error, for general use by minimally trained food service works and home cooks. None of these people are studying Pasteurization Charts or reading the studies on Bacterial Growth Rates under assorted conditions like, pH, Water Activity, Salt and Sugar content and their ability to bind water, Multiple Temp ranges to include High Temp/Short Time, Low Temp/Long Time and combination methods like guick high temp, then low temp finishing. Not too many years ago, the USDA insisted Pork be cooked to 165. Then 145 but the main concern is Trichinosis and that parasite is eliminated at 131 held for 6 minutes. So even the current USDA 145 is higher than necessary for pork...JJ

 

[Bearcarver]

Maybe not to you Bear, but delicious to me.

I don't even know what that comment means. "Maybe not to me what?"
I thought this thread was about safety & SV temps.

Bear

 

[johnmeyer]

The other thing that helps get food to temp quickly in a sous vide water bath is the circulator. In fact, as near as I can tell, that is the only reason the sous vide products have the circulator. By moving the water, the heat from the water is transferred more quickly, because the layer of water immediately next to the plastic bag is never allowed to cool down and "insulate" the bag from the rest of the water.