Power cut and bacteria!

In the General Sous Vide Questions Forum
So today I've come back from work to a bit of a nightmare. I put on a whole leg of lamb at lunchtime, and have come back 6 hours later to find that there's been a power cut. Temperature of the water when I left was 57 degrees, temperature when I got back was 39 degrees. I have no idea when in the afternoon the power cut happened as my partner had helpfully reset all the clocks.

So, the leg of lamb will have spent some time in the danger zone, somewhere between 1-6 hours.

What I'm wondering is whether the remaining cooking time (I was planning to take it out either tomorrow night or even Sunday lunchtime) will kill sufficient bacteria for me to ignore the multiplication that's happened in the last hours.

In case anyone's seen my other posts, this is not being served to an immune compromised individual



7 Replies So Far

How long was the whole leg at 57C? If it was there long enough, and your vacuum is perfect... then maybe **everything** died so that you wouldn't get new bacterial growth when the temperature went down...but 57C doesn't immediately pasteurize, so you could still have some bacteria alive, bacteria that could have grown back while the temperature was down.

You could up the temperature long enough to kill everything or at a high enough temperature but... some bugs (botulism) create toxins which remain even after the bugs are killed, plus botulism is Anaerobic so if you had any bugs there to begin with they'd still be alive.

As sad as it is to waste a whole leg of lamb...I don't think I'd risk it.

I do wonder if you could cook it with a more traditional method, at a pasteurizing temperature, after you rinse it really well, but that would pretty much ruin the leg for me anyway, so it may not be worth it.
Well, that's the unknown - I put it in at 57 and went back to work. For all I know the cut could have happened almost immediately and steadily dropped to 39 degrees. I was just wondering whether I could effectively pasteurise it after this 'blip', even though I'd be starting at a higher base level of bacteria, or if I'm missing something obvious which won't be killed in the process.

I'm kind of resigned to chucking it, though it's still on right now.
Sensibility prevailed and I threw it - a waste, but not worth the risk.
Sorry to disagree with Roberto Leibman, but I hope if he'll forgtive me correcting him on a couple of minor errors of fact.

The C Botulinum bug is killed like most other dangerous bacteria at varying speeds from 50C upwards. However, the reason it's dangerous is that in effect it lays eggs (endospores)inside its body and it's these eggs that are not destroyed by heat. In fact they resist temperatures up to 125C

Another error. Botulinum toxin (botox) is destroyed by heat, so if contaminated food is kept at temperatures above 70C or 80C, I forget which, for more than 5 minutes, it's no longer dangerous.

What I'd have done would have been to take the leg out of the vac pack - cut it into cubes and curry it. No bugs would have survived and the boiling would have destroyed any botulism toxin even if the almost vanishingly small possibility of it growing sufficiently HAD occurred.


But all that is too late. Let's hope it might be useful for someone else another time.
Thank you for all that info Ian. That distilled a lot of information I'd been trying to process into just a few paragraphs and made it so much clearer.

At the time, I definitely wasn't comfortable in my knowledge of the potential pitfalls, so I'm happy that I took the right decision. Knowing better now, I'd definitely do as you suggest and transfer it to a higher temperature process such as a curry.

Thanks again.
You're welcome Lee.

I note that Robertyo hasn't come back. I hope that doesn't mean he's gone off in a bit of a huff.

However as someone with a scientific background and who worked as a chef for many years, I feel it is important to be careful to give clear factual information, based on good research. Obviously, it's a "bad thing" for a chef to poison his clients, so I've read up a lot on Botulism - as well as several other nasties.
No, I didn't leave, just didn't check the "please email" thing, so I just didn't see your response.
I stand corrected. I was going from memory and from my understanding of the science, thanks... I do too have a scientific background and thus LOVE to be corrected when wrong.


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