The internet is often a source of tasty recipes and do-it-yourself projects. But when it comes to food preservation, the resource you find is often unreliable or not research-based. Such is the case with canning milk or other dairy products at home.
To date, there are no science-based methods for home canning milk, butter, cheeses, or other dairy products. The University of Kentucky Cooperative Extension Service, the National Center for Home Food Preservation, and the U.S. Department of Agriculture (USDA) all agree. All of these credible sources say to avoid any process for the home canning of these items. They also recommend against oven canning, open-kettle canning (food is heated, added to jars, and then allowed to seal), and making up or changing recipes to home can.
The home canning process is often used to preserve the bounties of your garden or a successful hunt. If done correctly, following USDA-recommended recipes, the results are a safe, shelf-stable product. These recipes have been tested to achieve the right temperature at the center of the jar of food. They also get to the proper heat for the correct amount of time. The proper time and temperature are needed because of the possible contamination of the bacteria Clostridium botulinum and its spores. These spores produce toxins. Many cases of foodborne botulism have occurred after individuals ate incorrectly processed home canned foods that were contaminated with the toxin. Armed with the right information, in this case a USDA-recommended recipe, processing low acid foods in a pressure canner destroys any spores of Clostridium botulinum. When acid is added, some foods may be processed using a boiling water bath process. This can prevent the growth of the spores. The correct time and temperature also kill spoilage-causing bacteria. If you follow USDA-recommended recipes, the products can be stored safely for up to two years, also providing you with a quality product.
Milk and cheese have pH levels that make them low acid foods and thus in the canning danger range. Waxed hard cheeses (Asiago, cheddar, Edam, Feta, Gouda, Parmesan) will not support growth of Clostridium botulinum, but the canning process adds water. This is another area of concern that scientist have not tested. Increased available water may allow Clostridium botulinum to grow and make canned hard cheeses unsafe. In addition, the canning process can kill the competitive “good” bacteria that help prevent the growth of illness-causing bacteria. Soft cheeses (Feta, brie, cream cheese, Camembert, chevre, Roquefort, and Gorgonzola) are naturally high in water and you must refrigerate them to delay spoilage. They contain sufficient available water to support the growth of botulism-causing bacteria. Thus, the recommendation against home canning these products
Milk is also the perfect environment for bacteria to grow. There are dozens of spoilage and foodborne illness-causing microbes associated with milk. Fresh milk must be refrigerated, fermented, or pasteurized. It is not recommended to consume raw. The process of pasteurization involves heating the milk to a high temperature (165 degrees F) for a short amount of time (15 seconds). Pasteurized milk is still perishable and needs to be refrigerated and used within two to three weeks.
We all want to consume safe, tasty products. Home canning research allows us to do just that for a number of food products. But not all foods are conducive to home canning. The next time you find something interesting on the internet you would like to try, ask yourself, “Does this person making the recommendation have the thermal processing knowledge or credentials to be posting the information?” If the answer is no, or you don’t know, keep looking for something new to try! More information on family financial education topics is available by contacting the Meade County office of the University of Kentucky Cooperative Extension Service.
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