Re-Heat Before You Eat! Home Canning Safety.

This article was taken from the March April 2011 Backwoods Home Magazine.  

Thanks goes to our attentive and caring customer who sent us this information.  :)


Under Ask Jackie

The title was: Running the pressure canner without water.

Peter Regan of Beaverton, Oregon 

Wrote to Jackie about her response to another reader, concerning the lack of water in her canner.  We are posting here the entire article "retyped" as it mentioned retorts in the conversation and we feel the entire article is a very viable piece of information for home canners using not only jars but retorts also.
There is no FDA or USDA information for retort canning for the home canner.  We express our experiences, they have no scientific FDA or USDA backing.  Can at your own risk!

Running the pressure canner without water

I'm a regular cover-to-cover reader of BHM, and I really appreciate your section on food preparation. However I must take exception to the answer you gave to Mary Wolfe in Issue #126 Nov/Dec 2010 issue (Oops-Waterless Canning). She forgot to put water not her canner before pressure-processing pint-jars of beef, but the jar lids did seal properly.  Your reply: 

"... Here's my guess: probably your meat is okay, as the jars all sealed and there probably was some steam generated by moisture in the jars during processing.  But I'd mark the jars and be awful sure I checked each one carefully upon use.  Look at the meat, open a jar, making sure it is still sealed well, then smell the meat. If all is okay, be sure to bring the meat to boiling temperature for 15 minutes before eating.... 

My comments are based on 20 years experience as a Food Safety Inspector, including numerous cannery inspections, completing the standard "Better Process Control" classes several times (*highly recommended for home canners, and required by law for canning retort. Operators see your state college food science departments). And completion of an Advanced Canning course provided by the FDA.  (I'm now retired.)  While I'm not a full-fledged Food Science Professor, or a certified "Process Authority" for a cannery, my professional opinion is as follows: 

1. The jars of processed meat have well-sealed lids:  This means that the contents of the container reached at least boiling temperature (212 degrees F) producing steam and forming a vacuum when cooling.  However, there is no way to know whether the contents reached the required full-processing pressure and temperature (10-15 psi of pressure / 240-250 degree temperature) and for how long.  The boiling temperature most likely killed all the food-poisoning and spoilage bacteria, but not the most critical spores of the botulinum bacteria. 

2.   Well-sealed lids also show that there was no re-contamination after processing.  But what is still present and viable, like the spores, can still be a problem.

3.  The time and pressure/temperature specifications in our canning manuals depend on heat transfer by the steam in the pressure cooker-canning vessel, continuously and to the entire surface of the jar and lid for proper heat penetration to the coldest spot inside the jar/container.  

Without water in the canner; 

a) heat was probably only transferred throughout the bottom of the jars; 

b) the jars were probably insulated somewhat by air remaining inside the canner, and

c) it is highly unlikely that the proper temperature/pressure could be maintained though the cook.

Conclusion:  It is highly likely that botulinum spores were still viable in these containers of meat, and produced botulism toxin in these jars within a week or two. 

Regarding your recommended handling procedures: 

1. Check for sealed lids: Yes, this shows that at least a boiling temperature was achieved inside the jar, and three was no re-contamination after processing.  (But botulism is still possible.) 

2. Checking appearance and smell of the product upon opening:  Yes, this shows that (more easily killed) spoilage bacteria were destroyed.  But, Botulinum spores, bacteria and toxin is odorless and does not produce viable changes.  Also, do not taste, even a little bit, to go along with your smell check.  Botulism toxin is the most deadly poison known--- even a fingertip dipped in the food for a taste can kill.  

3.  Bring the meat to a boiling temperature for 15 minutes for 15 minutes before eating.  Yes.  This procedure will destroy any harmful bacteria, as well as botulism toxin, that is in the food.  (However, please be careful how you handle the utensils.  Fore example, if a spoon is used to empty the jar into a pan for cooking, the spoons's surface may be contaminated and transfer residue elsewhere.)  This cooking procedure has probably saved hundreds of lives over the years.

As an alternative procedure, may I also suggest that it is safe to take the marked jars and run them through another canning cook process, without opening them?  Just follow the same time and pressure temperature recommendations for the original food product.  This may "mush" fragile vegetables like asparagus, but meats will only soften a bit more in texture.  There would be no safety issues with storing them away again.  

Again, Jackie, I greatly appreciate your column, and this is the first thing I've ever had any concerns about.  Keep up the good work! 

Peter Regan 

Beaverton, Oregon.

Peter, you are right.  The steam generated from the meat broth may not have been enough to have safely processed the meat.  I guess the old adage is right; when in doubt....reprocess.

Jackie