Botulism not only linked to home-canned foods
Every now and then I get a call or email that inspires a column. Last week, I received a call from someone outside of North Dakota who told me a tragic story that involved food.
According to my caller, a woman had prepared a main dish in a slow cooker. When it was done, she turned it off, covered it and let it stand on the counter for many hours. Later, she ate some of the food. Investigators determined that botulism was the cause of death.
My caller said he was attending her funeral, and he asked me if I could write something about botulism to warn others.
I was touched by the story. The last thing food safety specialists want to hear is that someone died as a result of seeking nourishing food.
I don’t know all the details. Maybe she made this dish many times previously. Perhaps she let it stand on the counter in the past but was fortunate that the toxin didn’t form the other times.
Although we cannot change the outcome, we can learn from this tragedy.
Has this happened previously? In 1995, the Departments of Health in Arkansas and Oklahoma investigated a similar case. The patient had been admitted to a hospital with dizziness, blurred vision, slurred speech, difficulty swallowing and nausea, which are hallmark symptoms of botulism. He needed to be placed on a ventilator to breathe.
The investigators learned that he had eaten home-canned green beans and stew with roast beef and potatoes. Contrary to what people suspected, the green beans were not the issue in this case. The stew tested positive for the botulinum toxin. It had been covered with a heavy lid and was allowed to stand for three days on the stovetop.
The U.S. Department of Agriculture recommends that perishable food spend no more than two hours at room temperature.
The number of botulism cases per year is relatively low, but the fatality rate is high. The symptoms usually show up 18 to 36 hours after eating the food.
Clostridium botulinum is the name of a group of bacteria usually found in the soil, so that is how the bacteria “hitch a ride” on vegetables. The bacteria can form spores (protective coats) that allow the organism to survive in nature’s harsh conditions. The toxin can form in low-acid, anaerobic (oxygen-free), warm conditions.
A covered container of lukewarm stew would meet the criteria to promote the formation of the botulinum toxin. However, placing leftover food in shallow containers in the refrigerator prevents the formation of the toxin.
We usually associate foodborne botulism with foods improperly canned at home, but other foods also have been implicated. For example, asparagus, green beans and peppers have been linked to many of the botulism cases associated with home canning.
Besides beef stew, onions sautéed in margarine and left in a pile on a grill, foil-wrapped baked potatoes left on the counter overnight, and pot pies all have been linked with botulism outbreaks. Mushrooms, ripe olives, tuna, liver pate, luncheon meats, sausage and smoked fish are among other foods that can support the growth of the toxin.
What are the lessons we can learn from the tragedy my caller described? If you make food ahead of time or have leftovers, be sure to cool foods quickly. Toxins can form in food that is not cooled fast enough. Some toxins can be inactivated by 10 minutes of boiling, but preventing the toxin from forming is the best way to protect ourselves.
As we would expect, thicker foods, such as chili or stew, take a longer time to cool. Here are the steps to cool foods quickly:
• Place thick foods, such as stew or chili, in shallow pans no more than 2 inches deep. Cut meat into thin pieces.
• Make your sink into an “ice bath” to cool foods quickly. Place food in a pan, then set it in the ice bath, stirring regularly.
• Leave out some of the water in the recipe and add ice near the end of cooking to chill the food.
If you plan to can vegetables, meats and other low-acid foods at home, remember that you need to use a pressure canner, not a water-bath canner. Pressure canners heat the food to about 240 F, which inactivates the spores that can produce the deadly toxin. Add acid, such as lemon juice or citric acid, to tomatoes to ensure they are at a safe acidity level for water-bath canning. Use safe, research-tested salsa recipes when canning.
Visit www.ag.ndsu.edu/food for a wide range of food preservation materials.
Here is a meal that goes together in minutes. You can prepare it right away or place the raw ingredients in a gallon-sized freezer bag for a ready-to-cook meal later.
Cilantro Lime Chicken
3 chicken breasts, boneless, skinless
Juice from 4 limes
1/2 bunch cilantro, chopped
1 (16-ounce) bag frozen corn
2 garlic cloves, minced
1/2 red onion, chopped
1 (14.5-oz.) can black beans, drained and rinsed
1 tsp. cumin
Salt and pepper, to taste
To freeze: Place all ingredients in a gallon-sized, zip-top bag and put in the freezer. Thaw in the fridge overnight.
To cook: Place in a slow cooker on low for eight hours. Heat to an internal temperature of at least 165 F. When done, shred meat and serve on tortillas with your choice of toppings. Chill leftovers in shallow pans.
Makes six servings. Each serving has 200 calories, 2 grams (g) of fat, 18 g of protein, 28 g of carbohydrate, 5 g of fiber and 85 milligrams of sodium.