Tag Archives: botulism

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 www.homefoodpreservation.net, the 2015 USDA Complete Guide to Home Canning (https://nchfp.uga.edu/publications/publications_usda.html) and So Easy to Preserve, 6th ed. (https://setp.uga.edu/).

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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.  https://www.cdc.gov/mmwr/volumes/68/wr/mm6810a5.htm

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How do you like your eggs? Scrambled, Fried…or Pickled!

Whether your eggs come from your backyard chickens, the grocery store, or the Easter bunny, you might find yourself looking for different ways to prepare and preserve your abundance of springtime eggs.

There are no tested, reliable home canning recommendations for keeping pickled eggs at room temperature that we are able to recommend. Eggs are a low-acid food, and it is possible for botulism to grow in areas of a boiled egg that have not been sufficiently saturated by vinegar. The density, thickness, and very low acidity of eggs (pH ranges between 6.4 and 9.0) all present challenges for adequate penetration of vinegar and sufficient acidification throughout all areas of each egg. To read more about a case of home-pickled eggs implicated as a cause of botulism in Illinois in 1997, click here.

Instead of going through the steps of a canning process, simply make delicious pickled eggs safely at home by following recipes and instructions designed for refrigerator storage. Be sure to wash all utensils and surface areas (including hands) very well and sanitize jars for 10 minutes in boiling water before filling with boiled eggs if you expect to keep them for more than several days. Keep pickled eggs refrigerated, and limit their amount of time out of the fridge to 2 hours or less. Give them about 2 weeks to season in the brine before tasting. Unless otherwise indicated, you’ll want to consume refrigerated pickled eggs within 2 to 3 months for best quality. You can find more pickling tips and recipes on the NCHFP website.

refrigeratorHere is a basic recipe, copied directly from the pages of So Easy to Preserve:

Refrigerated Pickled Eggs

16 fresh eggs

2 TBSP whole allspice

2 TBSP whole peppercorns

2 TBSP ground ginger

4 cups white vinegar (5%)

2 TBSP sugar

Cook eggs in simmering water for 15 minutes. Place eggs in cold water, remove shells, and pack into sterilized jars. In a pot combine vinegar, sugar, and spices. Bring to a boil, reduce heat, and simmer 5 minutes. Pour hot liquid over hard-boiled eggs. Seal. Store in refrigerator. Use these pickled eggs within a month. This recipe is not intended for long term storage at room temperature.

Recipe from: Andress, E.L., Harrison, J.A., eds. (2006). So Easy to Preserve, 5th ed. Athens, GA: University of Georgia Cooperative Extension. ©University of Georgia.

Botulism: Think Outside the Jar

Since it’s that time of year that foods may be prepared well ahead of time, then packaged and transported to be shared with family, friends, and co-workers, it seems timely to spread awareness about less-known situations that have the potential to lead to botulism: Did you know that it is possible for botulism to come from non-canned food items? As mentioned in a previous posting called “Botulism: Surprises”, botulism has been linked to other foods, including unrefrigerated salsa, baked potatoes in aluminum foil, garlic in oil, fermented fish, and honey. Following are a few true tales to provide important details and inspire caution…

In 1994, in Texas, 30 people were affected by an outbreak of botulism from restaurant dips made with baked potatoes wrapped in foil and left at room temperature (apparently for several days) prior to being used the dips. In this case, the spores of Clostridium botulinum (which are readily found in soil) survived the heating process (which is to be expected), remained moist, and were then so tightly wrapped in aluminum foil that oxygen was kept out of the packaging, creating an anaerobic environment in which the botulism toxin could form. Oil covering a food, as with garlic in oil, also creates an anaerobic environment.

real potatoes

Not even processing your homemade salsas but putting them in tightly sealed jars (again, an anaerobic environment) left at room temperature is a big risk. Botulism could result if the salsa is too low in acid, and other problems besides botulism could occur even in more acid salsas. Tomatoes (and figs and Asian pears) are borderline pH foods, so we see recommendations to add some acid to jars even before treating them as boiling water canned foods. Fermented fish and fermented vegetables that do not finish fermenting to a truly acidic pH are other examples of foods that might not be acidic enough to prevent the botulism-causing toxin from forming.

Another situation that has caused botulism is pickled eggs left at room temperature. In 1997, in Illinois, a 68-year-old man developed symptoms of botulism – double vision, inability to speak, difficulty breathing – that was traced back to homemade pickled eggs. Testing confirmed the presence of type B botulism toxin. To prevent the toxin from forming, pickled eggs should be stored in the refrigerator and only be at room temperature for serving time; limit their time in the temperature danger zone (40 degrees F to 140 degrees F) to no more than 2 hours. Pickled egg recipes and storage guidelines can be found on the NCHFP website.

Early in 2011, two people got botulism from eating commercially made potato soup intended for refrigerator storage but kept in their homes at room temperature.  One case was in Georgia and one in Ohio.  Both people bought the soups from a refrigerator case, left them out of the refrigerator at home for a long time and then tasted them.  Bad decision!  Each individual spent a long time in the hospital and then were transferred to rehab facilities with respiratory issues. Unfortunately we do not know the ultimate outcome today.

It may now seem like botulism can come from anywhere, but that’s not true; Clostridium botulinum bacteria require specific conditions to be able to grow and produce the botulism-causing toxin. Understanding what’s involved in the formation of the toxin will help you know how to prevent it:

In order to grow and produce the botulism-causing toxin, C. botulinum bacteria must be kept in a very low-oxygen (anaerobic) environment with a pH above 4.6 (low acid foods) and a relatively high moisture content.  If these conditions are met, any temperatures in a wide range around anyone’s “room temperature” and definitely above 40 degrees F will allow the bacteria to multiply and produce toxin.  (Sometimes the temperature even can be a little cooler than that for some types of C. botulinum and they will still multiply.)

Pressure Canner

Awareness and action is the key to prevention. To avoid botulism, avoid the risk of containing C. botulinum in a low acid, moist, anaerobic environment and if you do so (you canners out there know who you are), then be sure to process your low-acid food products in a canner equivalent to at least 240 degrees F (achieved when your pressure canner reaches the recommend amount of pressure, after venting, for your altitude) for the recommended amount of time.

Click here to view the full article of ‘Foodborne Botulism From Eating Home-Pickled Eggs —Illinois, 1997‘ from the Centers for Disease Control and Prevention. Here is the full publication ‘A Large Outbreak of Botulism: The Hazardous Baked Potato‘.  And here is the short story of botulism from potato soups in 2011.  

Why can’t I can what companies can?

As a home canner looking for new recipes to try out, you might sometimes be inspired by commercial products found on grocery shelves. But even after scouring through all your recipe books, magazines, and online resources there are still some products for which you cannot find home canning recommendations. Why is this? What do these companies have that you don’t?

Well, in summary, companies have two things that home canning does not have: 1) special equipment and 2) lots of money for research.

Commercial facilities have industrial equipment that can reach higher temperatures more quickly than what can be achieved at home. With specialized equipment, they are also able to control the consistency and maturity of ingredients. This control reduces the variability of the canning process, which allows for more reliable research (and therefore more product development) than can be done for home-canning practices.

Companies pay to conduct expensive research in order to determine safe product formulas and processing methods for each and every product. Even if just one ingredient is added to an already approved product, that new recipe must be carefully tested before being manufactured for sale. Acidity levels, water activity, and heat penetration are all critical factors influencing processing times, and these factors vary greatly among different recipes.

Proper studies to establish processing times for both commercial and home-canned recipes are crucial to the safety of canned foods. Without proper processing times, there is significant risk of botulism resulting from under-processed canned foods, especially low acid foods. Experimentally determining safe processing times requires a lot of time and money, and there is no easy formula to take into account the way that each product heats in each canning situation. Commercial and home-canning processes are not interchangeable. That is why there are fewer recipes and processes for home canning than many people would like.

For more information about heat processing of home-canned foods, read this ‘Backgrounder’ by Elaine M. D’sa.