Food Preservation: Setting the record straight on canning breads and cakes
Posted: March 18, 2015
Frequent questions about canning breads and cakes in glass jars surfaced this year at the 2015 PA Farm Show, where Penn State Extension featured an education booth on home food preservation. According to Senior Extension Educator for Food Safety and Quality Rick Kralj, the actual process of baking bread or cake in a jar should not be confused with canning. The product is baked in an open glass canning jar and then covered with a canning lid upon removing from the oven; however, there is no further canning process applied afterwards.
The application of this technique to preserve baked items is not recommended. The bread and cake recipes may call for the addition of fruit, liquids or vegetables, which actually increases the moisture content, making a rich environment for microorganism survival. In addition, the practice does not remove all oxygen, leaving some oxygen available in the jar for microorganism use. Many cakes and quick bread recipes often have little or no acid, resulting in a pH range above 4.6. A pH of this level will support the growth of pathogenic organisms that cause food-borne illnesses. There is a great concern that the hazardous bacterium called Clostridium botulinum (Botulism) may grow in these jars after they have been processed. Botulism is an often fatal food-borne illness and cases are reported each year of individuals who encountered Botulism poisoning through improper canning practices.
Studies conducted by many universities over the years have shown that some bacteria are heat-stable and can survive the baking process and then multiply in the breads during storage. Underbaked products were also found to be a serious food safety problem. When breads and cakes in jars are made for sale commercially by companies, they use additives, preservatives, and processing controls to ensure food safety of the finished product. Currently, there are no reliable or safe recipes for baking and sealing breads and cakes in canning jars and storing them at room temperature for extended lengths of time.
For food safety questions or concerns, Rick Kralj may be reached at email@example.com.