Tag Archives: foodborne illness

Botulism: Think Outside the Jar

Garlic and Oil

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.  

Ummm…what exactly is botulism? (Part III)

salsa in dishfish

Botulism: Surprises

Before moving on to the brighter sides of home food preservation, a few more interesting and perhaps less known facts about botulism:

  • Home canned products may be the most well-known source of botulism, but in recent decades botulism has also been linked to unrefrigerated homemade salsa, baked potatoes in aluminum foil, garlic in oil, traditionally prepared salted/fermented fish, and honey (the primary cause of botulism in infants).
  • This might startle you, but we actually consume C. botulinum spores regularly and they generally do not harm adults. Adult human bodies prevent the growth of spores, such that no toxin can be produced.

intestinesAnatomy Model

  • However, spores have been found to germinate, colonize and produce deadly poison in the intestinal tracts of infants. Therefore, USDA recommends that honey is not given to children under 1 year of age and that fruits and vegetables be washed very well before fed to infants.

Sleeping Newborn

  • Clostridium botulinum toxin is among the most toxic substances known.
  • Cases of botulism have been reported in which people showed symptoms only 4 hours after ingestion. The longest time reported between ingestion and illness is 8 days.

Information in the entry comes from the USDA factsheet Clostridium botulinum and So Easy to Preserve.

Beat the Bacteria Buffet

Spread cheer, not the worst foodborne illness of the year!

GRoasted Duckhealthy bread on wood

We love sharing foods this holiday season, but unfortunately, sometimes in the process we also share foodborne bacteria causing illness. Buffets and potlucks are particularly popular, but come along with certain risks. Make your hearty gatherings the most healthy (and happy!) by practicing these food safety tips from USDA.

Keep Clean
Wash hands, wash dishes, wash utensils, and clean kitchen surfaces. Wash well and wash often.  Invite your guests to also wash their hands as you welcome them.

Hand Washing 1Dish WashingHand Washing 2

Cook Completely
Cook foods to safe temperatures. Measure their temperature internally with a food thermometer, before removing from heat source. Cook beef, pork, lamb and veal steaks, chops, and roasts to at least 145°F. All raw ground beef, pork, lamb, and veal needs to be cooked to no less than 160°F. Poultry must be cooked to a minimum of 165°F. You can cook any of these meats to higher temperatures, but not lower.

Store Shallow, Serve Small
To store cooked foods before serving, store them in the refrigerator or freezer in a shallow dish to encourage rapid, even cooling. Most foods, and especially all meats, poultry, seafood, casseroles, and soups must be reheated to at least 165°F before eating again; serve them in small portions and continually replace platters when empty. This way, foods stay a safe temperature for longer and growth time for bacteria is minimized.

2:02 is Two Too Much 
It is best to discard perishable foods after they sit out at room temperature for more than two hours.  Otherwise, keep them below 40°F or above 140°F. Of course, it’s okay to keep out foods that are stored at room temperature for longer times, like uncut apples and crackers.

Kitchen TimerGarbage CanGreen apples in polished brown wood bowl

Cold means Cold, Hot means Hot
Use chafing dishes, slow cookers, and warming trays to keep hot foods at 140°F or warmer. Nest dishes in bowls of ice to keep cold foods at 40°F or cooler. Otherwise, keep swapping in foods from the oven or refrigerator.

Hidden in Handling
Remember that harmful bacteria capable of causing illness usually cannot be seen, smelled, or tasted. Three common bacteria found partying at food festivities are Staphylococcus aureus, Clostridium perfringens, and Listeria monocytogenes. If anyone does feel ill, please remind them to contact a health professional and describe their symptoms.

The information in this entry comes from the Holiday or Party Buffets Factsheet by the United States Department of Agriculture Food Safety and Inspection Service.