MSU experts discourage canning in multi-cookers
RAYMOND, Miss. -- Electric pressure cookers can help home chefs get meals on the table in just minutes, but food science experts said preserving fruits and vegetables in these appliances can be risky.
"We cannot recommend using electric pressure cookers for canning," said Courtney Crist, an assistant professor of food science with the Mississippi State University Extension Service. "Although some manufacturers have included recipes and a canning and preserving function on their digital cookers, these appliances have not been tested by the U.S. Department of Agriculture to ensure canned foods reach the correct temperatures to kill dangerous bacteria."
Extension recommends that cooks follow the instructions provided by the National Center for Home Food Preservation for preserving any food items at home to reduce microorganisms that can cause food-borne illnesses. Housed at the University of Georgia, the center uses the research-backed data supported by and gathered from USDA testing.
“If something about the food preservation process changes, including ingredients, jar size, preservation method and product particle size, the entire process needs to be validated for food safety to ensure a safe end product,” Crist said.
The USDA processing instructions were developed using a stovetop pressure canner that can hold four or more jars upright. These canners allow the food in the jars to reach the proper temperature and pressure for the right amount of time, killing harmful bacteria that could lead to food poisoning.
Processing times and temperatures differ depending on food acidity. Clostridium botulinum, the microorganism that can produce a deadly neurotoxin called botulism when consumed, is inhibited in acidic environments. Foods naturally high in acid, such as some tomato varieties and some fruits, have more protection against the growth of the bacteria. While rare, botulism spores grow in improperly processed, home-preserved products because the spores are resistant to heat and cannot be killed by boiling.
When preparing less acidic or nonacidic foods, such as fresh green beans, cooks must use a pressure canner. Proper sealing reduces bacteria growth and food spoilage.
Natasha Haynes, Extension agent in Rankin County and host of The Food Factor, said the multi-cookers she has looked into suggest canning only acidic foods, such as salsa and jams. However, even if cooks follow recipes provided by the manufacturer, they may not be assured of completely safe end products, she warned.
“Without access to data produced from testing electric cookers during the canning process, we can’t be sure that the food in the jars is hot enough for long enough to prevent food-borne illness,” Haynes said. “Jars have to be spaced correctly for steam to heat them evenly. There has to be enough water in the canner to produce the correct amount of steam. There is also no way to know if the cooker loses power due to electrical current surges, which can reduce the temperature and the pressure inside the cooker.”
Canning recipes written by the National Center for Home Food Preservation are specifically intended for stovetop processing and should not be used with an electric multi-cooker.
“It is important if taking the risk to use these electric cookers for preservation that you follow the guidance and suggested recipes from the manufacturer,” Crist said. “Food safety is the No. 1 priority. It is really important to do some research about an electric cooker before purchase to discover what support and resources the manufacturer provides for users. People should also read the manufacturer’s instructions for use and recommended recipes that can be used with the cooker.”
For more information about canning processes and preserving food, visit the National Center for Home Food Preservation web site at http://nchfp.uga.edu/.