Use Safe Methods When Preserving Food at Home
Commercially processed canned products have been recalled in the past several months for being contaminated with clostridium botulinum, which can cause botulism. However, 92 percent of botulism outbreaks come from home canned products, making safe home canning methods an absolute must.
In the past, our parents or grandparents boiled home canned green beans or other home processed foods for at least 20 minutes before eating them. Today, most people don’t have the patience for boiling canned food that long or don’t want their food to become mushy. That is why home canned food must be processed safely.
Low-acid foods, such as meat products and all vegetables, must be properly canned. Clostridium botulinum is a spore-forming bacteria that grows well in low-acid environments. Canning of these low-acid foods needs to be done in a pressure canner to kill all bacteria and render spores associated with bacteria inactive. University of Nebraska-Lincoln Extension NebGuides about canning directions specific to types of food are available at http://www.ianrpubs.unl.edu/epublic/pages/index.jsp.
Tomatoes and tomato-based products are right at the borderline of having an acid level low enough to protect from bacteria. Acid is added to ensure that the product can be safely processed using a boiling water bath method. Follow directions in the UNL Extension NebGuide “Let’s Preserve: Tomatoes and Tomato Products.”
Home-canned, low-acid foods should be processed with a pressure canner at temperatures at or greater than 250 degrees Fahrenheit (10 to 15 pounds pressure depending on the product and container size) in order to kill the spores formed by clostridium botulinum. The spores may survive boiling temperatures. In a jar with no oxygen, a high water content and low-acid environment, the ideal conditions are present for spores to convert into bacteria.
Once the bacteria start growing in the product, the bacteria produce a neurotoxin. This toxin causes health problems when ingested. Initially, symptoms may include weakness, double vision and difficulty speaking and swallowing. The toxin will impair respiration and then causes paralyzation and eventual death.
When a person begins experiencing double vision after ingesting contaminated food, they should seek immediate health care. Symptoms begin quickly, usually 24 to 48 hours after ingestion.
SOURCE: Julie Albrecht, Ph.D., food specialist
Ann Fenton
University of Nebraska Extension
Pierce County
