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rballard

Sous Vide mishap -- risking botulism?

13 posts in this topic

I've got some lamb riblets from a friend's pasture-raised lamb, which I received frozen; I brined the ribs overnight in the fridge and then put them in my sous vide setup at 145f for 36 hours. Unfortunately, I neglected to put plastic wrap over the water pot and due to evaporation my immersion circulator shut off at some point during the night last night. I don't know how long it was off for, but the water had reached room temperature by the time I found it.

 

I wouldn't serve these ribs to anyone else at this point, but I really don't want to throw them away and am wondering how much of a risk I'd be taking by eating them. They've got another 12 hours at 145f left, and then I was going to grill them before serving, so they should get re-pasteurized. The risk I see is if there were enough botulism spores to produce toxin that won't be destroyed by pasteurization. So I my questions are:

 

-- Does meat like lamb riblet generally contain botulism spores in the first place? It sounds like they're much more common in fruits and vegetables, or food that has touched dirt.

-- The vacuum bags didn't puff up at all. Does this mean that no significant amount of botulism grew?

-- Is botulism toxin just on the surface of the meat? If so, if I dipped the ribs into boiling water briefly to denature any botulism toxin on the surface, would I be making them safe to eat?

 

I know it's easy to say "when in doubt, chuck it", but I was pretty excited about these ribs and that'd be painful. So, how much of a risk is this?

 

Thanks,

- Rick

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Nobody can give you the assurances you ask for.

 

Unpuffed bags are a good sign but no guarantee.

 

And there's more to worry about than botulism.

 

62 C for 12 hours probably killed everything.

 

Feel lucky?

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Anna Nielsen aka "Anna N"

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I probably wouldn't serve them to other people, out of paranoia, but I'd eat them. Botulinum toxin breaks down rapidly with high heat, and unless you did something odd (rolling the meat, binding pieces together with activa, piercing with a jaquard tenderizer) you can presume the inside of the meat to be sterile. You can also presume that you pasteurized the bejeezus out of the outside, so the only thing that could still live there would be spores. C. perfringens generally doesn't produce significant amounts of toxin before being eaten, so botulinum is the obvious thing to worry about. The toxin would accumulate on the surface, if anywhere, and it's not heat-stable. A quick solution would be to brown the meat by deep-frying very briefly, which would get to all the surfaces. A relatively quick blanching, as you suggested, could work.

 

Here's info on time/temp for denaturing botox.

 

I'm NOT recommending this. I'm not a bacteriologist, and who knows what I'm leaving out. But I'd probably go for it I were the only guinea pig. I hate throwing out food.

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just toss them and start again

 

nothing is really lost this way

 

as you have learned something.

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Thanks all. You sufficiently scared me out of eating them as-is. Instead I looked up a chart of temperature/time for botulism toxin deactivation (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC291232/), which said that 40 minutes at 165f will do the trick. I turned up the circulator to 165 for the last hour of cooking. This didn't wreck the ribs... they were still plenty juicy :-)

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You lived, but note that pH and toxin type are specified in that study from the 70s that you cite. Neither of those were known in your ribs. I might've done the same thing, but...

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I looked up a chart of temperature/time for botulism toxin deactivation (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC291232/), which said that 40 minutes at 165f will do the trick.

 

Umm, where does it say that?  As I read it, Figure 1 on p.2 of the pdf suggests a deactivation time at that temp of at least an hour, with the first no-death sample at 85 minutes (or so) and the projected best fit line at 100 minutes.  Notice that all these samples were at pH 6.8.

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Nobody can give you the assurances you ask for.

 

Unpuffed bags are a good sign but no guarantee.

 

And there's more to worry about than botulism.

 

62 C for 12 hours probably killed everything.

 

Feel lucky?

I'm pretty sure it takes something like 10 minutes at 100C to degrade botulism toxin... ;-) Maybe he should make lamb stew???

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According to this more recent study, 5 minutes at 85°C should do the trick. Only the abstract is available for free. As always, beware free advice on lethal toxins ...

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What did they smell like? I get not wanting to waist food but i had instance where the meat for some reason came out smelling like baby poo. I had came to the conclusion it may have been mishandled during packaging at the grocery store. I wasnt eating something that smelled like poo so in the trash they went.

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The kinds of spoilage bacteria that can lead to baby-poo smell are understood much less well than pathogens or pathogenic toxins. Some of them can reproduce in temperature ranges that kill all the relevant pathogenic organisms. It's rare, but it may be possible to do everything by the book in a low temperature cook and still get a bag of stank.

 

But this is completely unrelated to health hazards like botulinum toxin. The presence of one doesn't tell you about the presence of the other. The organism that smells like poo can't harm you ... not that you'd be tempted to find out.

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