Preface - The Purpose of this Discussion: While neither I nor anyone here are health experts, we owe it to ourselves to stay safe when cooking and posting to this forum. This discussion is the result of months of research, not only by me but teesquare as well. This was not done haphazardly!
There is one particular condition NOT covered by the current sous-vide guides that I've seen:
Cold-smoking meat prior to sous-vide cooking.
There may be a sous-vide guide that includes this info, but we haven't seen it and felt, that since we do a lot of smoking around here, this info was needed.
While doing some research on this subject, I took a practice test of the ServSafe certification test. Ironically, one of the questions that came up was about sou-vide.
Here's a screen shot
(Click to enlarge):
Don't Fear Sous-Vide!!!Please understand, while there is some legitimate concern, this cooking method has been well researched.
As long as you adhere to recommended time/temp tables, you can be assured that you are cooking safely!
YOU are responsible for your own health and safety, as well as those you cook for. PLEASE BE SAFE - STICK TO THE MINIMUM TEMPERATURE AND TIME RECOMMENDATIONS!!!There are a few really good guides out there. This one is considered, by many, to be one of the best:
Douglas Baldwin's Sous-Vide Guide
And now, on to our topic.What prompted me to start looking into this was two different forum members who PM'ed me a few months back asking my opinion on cold-smoking some burgers, then vac-sealing them prior to cooking.
A Few Indisputable Facts:1) Ground meat, especially pre-packaged, requires some extra precaution, NO MATTER WHAT THE COOKING METHOD.
2) Cold-smoking ANY meat not cured with nitrates/nitrites carries some risks, and special care, NO MATTER WHAT THE COOKING METHOD.
For our purposes, cold-smoking refers to smoking at temperatures below 165° F (74° C).3) Ground meat, especially, should NEVER be cold-smoked unless it's been cured first with a nitrate/nitrite cure! It's too risky. This is an old sausage maker's rule and Sous Vide does NOT change this!How does cold-smoking create an extra hazard?There's a common notion that smoke, alone, will preserve meat. After all, our forefathers and natives preserved meat using smoke, right?
While it's true that smoke contains carbolic acid (phenol), which is a preservative, the meat was typically hung on racks angled over OPEN fires, NOT in a cold-smoke chamber. THERE IS A DISTINCT DIFFERENCE!
Smoking on open racks still allows for oxygen to circulate around the meat. Cold smoking in a BBQ pit or electric smoker, however, creates an oxygen-depleted environment and THIS, combined with the associated temperatures, is where the problems lies. It creates the perfect conditions for anaerobic bacteria to thrive.
What is Anaerobic Bacteria?Aerobic means "having oxygen."
Anaerobic means "lacking oxygen."
so...
Aerobic Bacteria - are those that need oxygen to survive.
Anaerobic Bacteria - do NOT need oxygen, and can survive and/or thrive in an oxygen-depleted environment, depending upon the type.
There are two basic types of Anaerobic Bacteria:
Facultative Anaerobes - such as E. Coli & Salmonella can live in both oxygen rich or oxygen deprived environments. They are not nearly as dangerous as obligate anaerobes when it comes to cold-smoking. This is because in an oxygen-deprived environment, faculative anaerobes simply switch over into a fermentation mode until killed off by pasteurization temperatures.
Facultative Anaerobes - WikipediaHowever...
Obligate Anaerobes - such as Clostridium Botulinum, given the right temperatures, thrive and reproduce in oxygen deprived conditions. These types of anaerobes are particularly dangerous because as they propagate they release toxic spores which are resistant to temperatures below 230° F
Obligate Anaerobes - WikipediaWhy not cold-smoke Ground Meat?Ground meat is NOT the same as cooking a whole cut of meat. With whole cuts of meat, bacteria that normally lives of the surface gets destroyed quickly enough under normal cooking conditions, to prevent problems. With ground meat, however, that bacteria gets mixed into and throughout the meat when it's ground, so it's now in oxygen deprived conditions. The only thing keeping the anaerobic bacteria in check are refrigeration temperatures of 40° or less.
Under normal cooking conditions, burgers, meat loaf, sausages, etc. are cooked to safe internal temperatures quickly enough to prevent problems.
Cold-smoking uncured ground meat creates a perfect breeding ground for C. Botulinum to propagate and release enough spores to exceed toxic levels. This in turn can cause botulism poisoning which can lead to paralyses and even death.
Botulism - WikipediaHow does this tie into Sous-vide?Sous-Vide temps, given proper time, will pasteurize the meat and reduce anaerobic bacteria to safe levels. HOWEVER, normal Sous Vide cooking temps WILL NOT destroy toxic C. Botulinum spores.
From the Wikipedia sous-vide entry:
...Pasteurization kills the botulism bacteria, but the possibility of hardy botulism spores surviving and reactivating once cool remains a concern as with many preserved foods, however processed...
Consider this for a moment: It's well known that canning green beans, and other non-acidic foods, requires Pressure Canning which allows water to reach high enough temperatures to destroy any possible C. Botulinum spores and toxin.
What Sous-Vide Time & Temps are required to destroy C. Botulinum Spores?The following FDA data shows that, even with sous vide, C. Botulinum spores (type E.) require an exposure of 100 minutes at 158° F (70° C) for the toxic spores to be destroyed. And, of course, higher temps will destroy them quicker - exposure to temps greater than 230° F (110° C) will destroy the type E. spores in less than 1 second.
Other values to be noted are the D-value of 36.2 min (k = 0.064/min) for Bacillus cereus spores at 95 °C and 100 min (k = 0.023/min) for C. botulinum non-proteolytic Type E spores at 70 °C. When expressed at 110 °C, these D-values become 1.18 min for the B. cereus spores and less than 1 sec for the Type E spores.
Excerpt from: Section 1.2.2.2. - Thermal processes, U.S. FDA Kinetics of Microbial Inactivation for Alternative Food Processing Technologies - FDA
Staying SafeHow can I safely get smoke flavor into ground meats?There are a couple of easy ways:
1) Add a few drops of liquid smoke to the ground meat and mix it in.
2) Add some smoked paprika to the ground meat and mix it in. Since paprika is a dry product it cannot harbor the food-borne pathogens that cause concern (E. Coli, Salmonilla or C. Botulinum). This trick works great!
What about whole cuts of meat - what's the risk?Even whole cuts of meat carry extra risk
if cold-smoked first.Your choice here is quite simple. Either:
1) Don't Do it. Instead use a little liquid smoke, or smoked paprika.
3) If you DO risk it, keep your pit as cold as possible, keep it under 30 minutes, and BE ABSOLUTELY SURE TO SEAR THE OUTSIDE OF THE MEAT BEFORE serving it!
Searing temps are normally well above 230°, so a quick sear should take care of any spores present on the outside of the meat.
As with all else, when in doubt - ERR ON THE SIDE OF SAFETY and let common sense rule!There are more resources available. If you have a good one, PLEASE post it in this thread!
