Botulism in sous vide leftovers

Hi everybody,

I've been cooking sous vide for slightly over a year now, and been trying to educate myself about food safety as much as I can. However, there's one question that I keep coming back to, and couldn't find an answer for:

Once I open the bag of anything cooked sous vide, is there still an elevated botulism risk, in comparison to any other cooking method? Specifically, if I made a big roast for dinner (to serve immediately), and ended up with leftovers, are there any special precautions I should be taking? On one hand, the leftovers chilled at something between room temperature (worst case scenario) and fridge temperature (best case scenario). On the other hand, the vacuum is gone, so is it still any different than traditional cooking methods?

Thanks in advance!

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Brandon_Byrd_40557

Once the bag is open, the food is in an aerobic environment. At that point, there's no difference between leftover food cooked SV and "normal" leftovers with respect to botulism risk.

FrankM_3301

A couple of points to add to Brandon's comment:

Not sure where you are located, but in the US, botulism is extremely rare (less than 150 cases per year), and only 15% of those cases are foodborne. Open wound botulism is more common (20% of cases), and I bet you've never even heard of that! I hadn't until I looked it up. The highest risk of foodborne botulism is improper canning of vegetables in low acid environments.

Cooking sous vide, whether or not you vacuum seal, is not a food preservation technique. The vacuum is irrelevant regarding safety. Consider sous vide cooking the same way you might consider traditional cooking. So, you might create other risks with improper cooking and cooling of your roast, but it's probably not a risk of botulism.

Eladz_939661

Aside of how rare botulism actually is, I'm pretty sure cooking sous vide is a higher botulism risk than other cooking methods due to the anaerobic environment created in the vacuum sealed bag, which is essential for the growth of the bacteria.

brian_martin2001

See Douglas Baldwin's response in this thread: https://www.chefsteps.com/forum/posts/botulism-2

A little information without really understanding is a dangerous thing

Eladz_939661

I actually read the entire post before posting this question. I did not see an answer to my question in there, and his response does support my understanding that botulism risk is greater with sous vide than with most traditional cooking methods given the typically low temperatures used when cooking sous vide.

brian_martin2001

Son of a bitch!

@Eladz_939661 apologies about the double notifications. There is a known issue with this site when the comment thread gets too long, the messages automatically remove themselves. It's an unresolved issue.

My message was something to the effect of:

Take a deep breath.

You claim to have read the entire post. In the post, a far more learned man than most folks you'll run into explains, rather well, why C bot is not a reasonable risk. You interpret him telling us that it's not a reasonable risk as it's an increased risk. When you interpret him saying that it is not a risk, as it is a risk, what else is there to say on the matter?

If you truly believe it is a risk, and won't listen to scientific data stating it is not a reasonable risk, then, for your own well-being, it would be advisable for you to quit while you're ahead.

Not really sure why you're in a tiff over that, but you do you.

Eladz_939661

Allow me to quote:

"Cooling, storing, and reheating: If you plan to preserve the food for later, this is where the botulism risk becomes significant. The first thing is making sure the cooling is fast enough that the spores don't become active bacteria – remember the lag I mentioned earlier – so the risk of growth is lower at refrigerator temperatures."

Since my original question referred to cooling the food, and I do indeed interpret "botulism risk becomes significant" as an increased risk rather than as not a reasonable risk, I still stand by my question.

brian_martin2001

This is only if you are maintaining an anaerobic environment. Allow me to quote you:

"Specifically, if I made a big roast for dinner (to serve immediately), and ended up with leftovers, are there any special precautions I should be taking? On one hand, the leftovers chilled at something between room temperature (worst case scenario) and fridge temperature (best case scenario). On the other hand, the vacuum is gone, so is it still any different than traditional cooking methods?"

There is no more vacuum. The product is exposed to oxygen. Clostridium botulinum is an obligate anaerobe. This means oxygen is poisonous to viable cells. The only thing that could be remaining are spores, which, unless you once again deprive them of oxygen, then reheat at a lower temperature, and leave it there, there is no reasonable risk.

If you have a difference scenario, where you do not take it out of the anaerobic environment, this changes things greatly, but, if we are going off of what you originally posted, in the start of this discussion: there is no reasonable risk if you follow all the steps you indicate.

Eladz_939661

Thank you, now that's a proper answer to what I believe was a very legitimate question.

However, I'm still wondering regarding this quote, from Douglas Baldwin's A Practical Guide to Sous Vide Cooking (albeit in a slightly different context):

"While O’Mahony et al. (2004) found that the majority of pouches after vacuum packaging had high levels of residual oxygen, this doesn’t imply that the Clostridium species – which require the absence of oxygen to grow – aren’t a problem since the interior of the food often has an absence of oxygen."

brian_martin2001

In physical action:

Let's say there are spores (the type of cells that cause the toxins) on your meat. You heat up your meat in the bath, and some start to germinate: creating a few viable cells and some toxins. Unless you leave them in there for an extended period of time, as indicated in the post i directed you to, not much of a risk here.

Now you take it out of the bath. Obligate anaerobic cells (the viable cells capable of rapid reproduction) die off immediately in the oxygenated environment. The only potential risk are the spores.

Unless you're a sadist, someone who doesn't like food (which if you're going through all the trouble to do this work for you and, likely, family/guests/other folks doesn't seem likely), or hate your guests, chances are you're going to sear the meat. This will be either in an oven or a skillet/pan. Spores will die at temperatures over 240°F. Temperatures needed to kill off these spores are well below the temperatures needed to sear meat. Now most, if not all of the spores have been murdered.

So, unless you put the left overs back in a bag, vacuum seal it, leave it at a temperature somewhere in the rapid growth range for C bot. for an extended period of time, and also assuming there are even enough spores remaining to pose a problem, there is no reasonable risk.

Steven_Davis_1132102

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