Stop/start Cook

Quick question - have a 48hr brisket cook happening, and after approx. 12-14 hrs at 60C my Anova stopped - and it was while there was no one at home to watch it. By the time I caught it the bath temp had dropped to about 25C. Got it going again straight away, and it has another 27 hrs to go - will it be safe to eat? It’s been pasteurised once in the first 12 hrs, and will be a second time I guess…

Hmmmmm… while, yes, it has been pasteurised and will be so again pasteurisation at those temperatures don’t kill off Botulinum. Under normal circumstances it is rendered inactive at cooking temperatures so you don’t need to worry. But in this instance, when the temperature dropped below the 54C mark it may have become active again and we don’t know for how long. Sure, when the temp heads up to 54C it is once again rendered inactive but the toxins produced while the Botulinum bacteria were potentially having their little party are the problem. These toxins are deadly.

You’d be pretty much playing Russian roulette.

Thanks Ember. I was planning to cook it in a Weber to finish - so a couple of hours at what 100C+? Will that fix things?

You would need the internal temperature to reach sufficiently high to destroy botulinum toxin. That’s 80+C…right to the core. Somewhat loses the benefit of having cooked it sous vide.

The general food safety rule is for cooked food to be kept above 60C. Cooling food mus be reduced from 60C to 21C in 2 hours then 21C to <4C in a further 4 hours. Then theoretically if you found the Anova at 25C it should only be at that temp for 2 hours. The greatest risk is spore forming mricobes, particularly Clostridium botulinum. As you probably had the brisket in a vacuum pack the risk is higher as CBot is anaerobic (doesn’t need oxygen). To kill this microb would take 300hrs at 100C. Even then, its toxin is not destroyed by heat. 1mg of CBot toxin can kill 100,000 people…sorry, I’m a Food Scientist and very risk averse when it comes to these conditions.

Only non-proteolytic CBOT bacteria can be killed (6 decimal reductions) at 80C for 60min, or 90C for 25min. This is the form of CBOT that can produce toxins at 4-10C (refridgerator). Othe proteolytic variants will sporalate and produce toxins if held at 30-40C for several hours. These are the ones that are only killed at 100C for 300hrs or 121C (pressure cooker 15psi) for 10min.

How much beef brisket has Botulinum in it? Is it universal?

It’s hardly something that gets tested.

Given the deadly nature of the toxins is it worth the risk? For a meal?