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Let’s Taco ’bout Botulism.

Let’s Taco ’bout Botulism.

In late April of this year, there was an outbreak of botulism due to contaminated nacho cheese at a gas station outside of Sacramento, California. The issue is no longer a threat, as the lot of cheese has been recalled and was discarded on May 5, 2017. However, the outbreak took its toll on nine people which were hospitalized, and one person died. Incidents such as these remind us of the importance of proper food preparation and preservation.

Seemingly innocent gas station food proved to be deadly in Sacramento.

Botulism is caused by the bacteria Clostridium botulinum. This Gram-positive organism has caused documented cases of illness dating back to the 18th century. When we think of preserved foods, we usually think they are safe. After all, isn’t that what preserved means? However, low oxygen conditions can promote germination of this spore-forming anaerobic organism.  Improperly processed canned and jarred foods are some of the most common culprits. However, as we see with the nacho cheese case, this can be found in any container that lacks oxygen.
Another cause for infection from botulism is from wounds, often relating to intravenous drug use.
Of all the documented cases, the most common occurrence of botulism is actually in infants. Infants who ingest the spores become colonized in the gut. Honey has been linked to a majority of these cases, and therefore, it is advised that honey not be fed to children less than 1 year of age.
Although botulism infections usually last one to ten days, some cases can become more severe. The man who died in the nacho cheese incident was in the hospital for several weeks on a ventilator before his eventual passing. While the disease is fatal in about three to five percent of cases, it can usually be treated with an equine-derived antitoxin. However, complications from using this antitoxin can arise, such as serum sickness and anaphylaxis. Therefore, it is not recommended for use with infants. Since infants are the most affected age group for disease, in 2003, a human-derived antitoxin was developed, giving a new treatment option for infants who have the misfortune of contracting this disease.

Contrary to popular belief, Clostridium botulinum itself is not actually what causes the illness; rather, it is the Botulinum neurotoxin it produces, which is the most lethal toxin known. The toxin, which is released upon sporulation, causes blurred vision, drooping eyelids, slurred speech, and

Clostridium botulinum showing spore formation. Simple boiling cannot kill the spores. Increased heat under pressure is needed.

even paralysis. Botulism toxin exists in seven different serological forms, which are labeled with the letters A-H. Types A, B, and F can be proteolytic, making detection easier since they give off a rotten odor. All serotypes affect humans, except C and D, which only affect animals. In the United States, virtually all reported cases have been due to types A and B.

Prevention of bacterial growth and its associated spores is not difficult. Though the nacho cheese travesty made headlines, cases usually arise from home-preserved foods. Hopefully, anyone that is practicing this hobby knows the dangers associated with canning and jarring foods and usually understands the proper precautions that need to be taken. For people new to food preservation, the USDA and CDC lists some important instructions in home canning, including taking special care for foods that have low acid (pH > 4.6). Never eat from a can that is bulging or leaking. Never eat food that is foamy or smells bad. When in doubt, throw it out!
Being a fairly rare disease, the case in Sacramento was shocking, to say the least. In 2015, there were 39 botulism cases linked to food. The largest outbreak was due to potato salad at a potluck where 27 people became ill. As we are coming up on summer, special precautions are needed to defeat this potentially devastating foodborne disease
By Trevor Thorsen
Technical Support Specialist
Hardy Diagnostics
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