Unsafe Canning Methods

it is important to recognize that there are canning methods that used to be considered safe that are now considered unsafe you should avoid these methods of canning the open kettle method involves pouring hot food into jars placing the lid and band on the jar and allowing the heat of the food to cause the jars to seal this is also called the hot fill method this method is not safe open kettle canning does not provide enough heat to adequately destroy molds yeasts and bacteria and it does not drive enough air out of the jars to create strong vacuum seals another unsafe method is oven processing where jars are filled with food and placed in the oven heat May not be evenly distributed inside the jars while in the oven preventing food from reaching the proper temperature this can also be dangerous because the jars are not designed to withstand dry heat or oven temperatures and may explode causing injury do not use old cookbook recipes that have directions for oven canning recently some models of electric multicookers have been marketed for pressure canning using USDA methods the machine dials may include a setting marked for pressure canning some instruction manuals include directions for canning high acid products such as pickles and jams and jellies products that can be easily processed in a boiling water bath others say to follow USDA directions for canning low acid Foods in their Appliance the entire thermal process including the heat up and the cooldown steps contribute to the destruction of harmful microorganisms electric multi cookers tend to heat up and cool down quickly since heat transfer and lethality curves have not been specifically studied in this environment with this type of appliance 10 State Extension and the USDA do not recommend using a multicooker for canning you may find directions for canning in microwave ovens slow cookers crockpots small electric pressure cookers the dishwasher or even the sun however these methods can be extremely dangerous and are not recommended the inversion method also called flip canning involves filling jars with hot food and turning the jars upside down to cool it is another version of open kettle canning and is sometimes used with heat processed foods while you might find directions for doing this with any kind of food it is most commonly used for sealing jams and jellies while some jars May seal it is more likely that the movement of the jars will disturb the seal and cause its release therefore don't use this method finally you should avoid the use of aspirin canning powders or chemicals that try to replace the heating process Al together to be safe the recommendation is to use a pressure caner for low acid foods and the boiling water bath or atmospheric steam can Center for high acid foods Penn State extensions home food safety website the national Center for home food preservation and the USDA complete guide to home canning all have research based information on safe canning practices