This spring and summer, gardens popped up everywhere:  from empty inner-city lots to downtown rooftops to the White House lawn.  As summer winds down and an overabundance of cucumbers, tomatoes, and other produce threatens to overwhelm gardeners, options present themselves. Option 1: Donate your surplus garden produce to your local food bank. Option 2: Preserve your harvest so it can be eaten throughout the year. Before you opt for Option 2, assess the equipment you are using and any recipes you plan to follow to make certain they adhere to the recommendations published by the National Center for Home Food Preservation.  Food – even the food you grow in your garden – can be contaminated with pathogens, and the dangers associated with improperly canned food are serious. Foodborne Illness Associated With Canning Clostridium botulinum (C. botulinum) is the name of a group of bacteria commonly found in soil.  C. botulinum itself is harmless; however, when C. botulinum or the spores it produces are exposed to a moist, low-acid food, a temperature between 40 and 120 degrees Fahrenheit, and less than two percent oxygen, they can produce botulism, a deadly toxin. Symptoms of botulism poisoning can occur as early as six hours or as late as ten days after the ingestion of botulism-tainted food.  Most people experience double vision, blurred vision, drooping eyelids, slurred speech, difficulty swallowing, dry mouth, and muscle weakness.  If undetected and untreated, botulism can cause paralysis of the arms, legs, trunk, and respiratory muscles.  Respiratory failure and paralysis associated with botulism require intensive medical treatment, including assistance breathing with a ventilator.  Patients who experience these severe symptoms of botulism poisoning typically require weeks or months of outpatient therapy after their acute illness has ended and they are released from the hospital. Stay Safe – Know Your Stuff Improper canning could result in an environment ideal for the growth of botulism toxin within your jars of peppers, asparagus, or other low-acid foods. Washing the foods you can does not completely eliminate botulism spores from a food’s surface.  The only way to ensure botulism spores have been eliminated in canned, low-acid foods is to use a properly functioning pressure canner to heat the food to a temperature of 240 to 250 degrees Fahrenheit and keep it there for a sufficient amount of time to kill the spores.  Recommended times vary by type of produce being canned, and pressure varies by altitude. Home canners with questions about safe canning techniques should call their local university extension service.