Category Archives: Storing Canned Foods

Learn Before Canning Vegetables

Another tragic story has been told about botulism poisoning resulting from improperly home-canned peas. Three women arrived at a New York hospital on morning last summer with acute nausea, dizziness, blurred vision, slurred speech, droopy eyelid, thick-feeling tongue, and shortness of breath. This was about 14 hours after they shared a homemade potato salad containing home-canned peas. (Of course, not the most common type of potato salad to many!) CDC released botulinum antitoxin that was administered to all patients about 12 hours after arrival at the hospital. All three patients survived, BUT, two developed respiratory failure requiring intubation and mechanical ventilation in the emergency room and the third was intubated that evening.  All three did require prolonged intensive care, with a range of 34-54 days, and rehabilitation.

Because a family freezer malfunctioned, one of the patients home-canned commercially frozen peas to “save them”. This was done 1-2 weeks before consumption. It turns out this person used directions for preserving a peach preserve in a boiling water canner, unaware that low-acid vegetables needed pressure canning to eliminate spores of C. botulinum. This is a good reminder that frozen vegetables may contain these spores as well as fresh ones. After processing, one of the jars did not seal so she refrigerated it. These are the peas consumed in the potato salad.

Yes, our USDA guidelines say that foods in jars not sealing after processing could be refrigerated and consumed within several days. HOWEVER, this is for jars correctly processed in the first place that did not pull a vacuum to seal the jar. Toxin was recovered from the jar and leftover food in the potato salad bowl. And that toxin matched that in stool specimens from two of the patients. Yes, it was those peas.

The closed jar of peas containing spores of C. botulinum held in the refrigerator for 1-2 weeks did indeed produce toxin. These spores like a low-acid, moist, oxygen-free environment. I wonder what the refrigerator temperature was, also.

dial=gauge pressure cannerPlease use recommended, science-based processing methods for home canned foods, especially low-acid ones. And if processing errors occur, discard the food or reprocess according to recommended guidelines within 24 hours. And, this is a reminder that even foods made with commercially processed ingredients can lead to serious consequences including death, if canned incorrectly.

See, the 2015 USDA Complete Guide to Home Canning ( and So Easy to Preserve, 6th ed. (


Reference:  Morbidity and Mortality Weekly Report, 68(1):251-252. March 15, 2019. Notes from the Field: Botulism Outbreak Associated with Home-Canned Peas — New York City, 2018.


What Lies Beneath: Let’s Clean Up Jars for Storage

A home canner recently asked me about “mildew” or mold that had appeared under the rijarswithbandsng bands on the canned jams and relishes she had put up a few months ago for holiday gifts.  That then reminded me about something I noted while judging canned foods at a large fair this past fall. A much larger portion of the fair entries than usual had mold growing under the ring bands,  as well as sticky residues on the jar threads and inside the bands. So let’s review some best practices for storing your home canned prizes to keep this from happening.

Lids and sealing areas of the jars should be washed off and dried before storage.  This is recommended even though you might not see food spill as you fill jars or apply lids, or moldyjarthreadson the outside of jars after processing.  Sometimes small amounts of starches or sugars in your food are there even though not very visible.  These residues can support the growth of mold with even a little bit of humidity in the environment.

After processing jars, make sure they are vacuum sealed before storing. Follow the lid manufacturer’s directions for testing for seals.  For example, if you use the very common two-piece metal lid system, after cooling jars for 12 to 24 hours, remove the ring bands.  Make sure that the flat lid is slightly curved down in the center and no longer springs back when pressed in that center.

When you’ve used a lid with a ring band, if lids are tightly vacuum sealed on cooled jars,
removejarswithoutbands ring bands to wash the lid and jar to remove food residue.  Then rinse and dry jars thoroughly. We recommend storing jars without ring bands.  If mold does start to grow on them, or if seals are broken, you are more likely to notice this and won’t be surprised when you go to use the jar. The bands can also be washed and dried and stored separately for re-use later.  At this point, it is the vacuum seal holding the lid tightly in place, not the ring band.

Label and date the jars and store them in a clean, cool, dark, dry place. For best quality, store between 50 and 70 °F. in low humidity.  Even with cleaned and dried jars, dampness may corrode metal lids.  Enough corrosion and you could even lose your seal.

Do not store jars above 95° F or near hot pipes, a range, a furnace, in an un-insulated attic, or in direct sunlight. These conditions may hasten loss of quality during storage.  Dampness may corrode metal lids, break seals, and allow recontamination and spoilage.

For more on recommended canning procedures, visit the National Center for Home Food Preservation.