Friday, April 10, 2009

Food Safety Issues

Reading about the recalls of packaged salad mix and packaged spinach got me thinking about toxins that can cause illness, specifically E. coli and Clostridium botulinum, commonly referred to as botulism. We live in strange times, indeed, when women have botox injections to smooth out wrinkles. Yessir, nothing like pumping your face full of deadly poison to get that baby-smooth complexion.

What is botulism? Glad you asked.
Botulism is caused by a toxin that is produced in food by the bacteria, Clostridium botulinum, which is found in soil all over the world. The soil in the western United States is high in type A Clostridium botulinum, which is the most dangerous type to humans. Alaska and Washington have the highest rates of botulism occurring in soils.

This bacteria forms spores, which are very resistant to heat, chemicals, and physical stress. When the spores grow, they produce the deadly neurotoxin that causes botulism.
The frequency of botulism cases is rare, but each year several outbreaks occur. Often these are caused by improperly home-canned foods. Fish, green beans, corn, beets, spinach, asparagus, and chili peppers are the most common foods implicated in botulism cases. Recently a case involved home-prepared “pickled” eggs.

Several conditions are necessary for a botulism outbreak. First, the botulinum organism must be in the food. Second, the acidity level must be low. The organism cannot grow when the acid level is high. A pH level of 4.6 or less means conditions are not right for the growth of Clostridium botulinum. Most types of this organism grow best at warm temperatures; however, growth has been observed at temps as low as 38 degrees Fahrenheit and as high as 118 degrees Fahrenheit. The organisms cannot grow if air or free oxygen is available. Oxygen-free (anaerobic) conditions occur when food is canned.

Home food preservers understand the necessity for pressure canning foods that are low acid. That means processing these foods at higher temperatures than just boiling, if we are to destroy the extremely heat-resistant botulism spores. Just because your jar has sealed, doesn’t mean you have a safe product. Processing foods under pressure raises the temperature inside the canner to a level that does destroy these nasty spores. That temperature is 240 degrees Fahrenheit and can only be achieved by pressure canning, which can be thought of as simply “higher-temperature” canning. Properly home-canned food is safe. For an extra guarantee of safety, home-canned veggies, meat, and fish may be boiled for ten minutes at 1,000 feet altitude before eating. Boiling destroys the botulism toxin. Remember to add an additional minute boiling time for each additional 1,000 feet of elevation.

Next week we’ll finish up this delightful topic. A parting thought: mistakes most often occur at two times in our lives. The first time is when we are learning a skill, and the second is when we get sloppy, careless, and take shortcuts, because we have been doing something for a very long time. It’s good practice to review the rules and instructions before we begin anything. Better safe than sorry, to use an old and very true aphorism.

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~ I'm the author of Headwind: The Intrepid Adventures of OSS Agent Katrin Nissen. If you're a WWII buff, you'll like it here!