Michigan
State University Extension
Preserving
Food Safely - 01600940
10/13/97
Open-kettle canning and the processing of freshly
filled jars in conventional ovens, microwave ovens, and
dishwashers are not recommended, because these practices do
not prevent all risks of spoilage.
Steam canners are not recommended because processing
times for use with current models have not been adequately
researched. Because steam canners may not heat foods in the
same manner as boiling water canners, their use with
boiling-water process times may result in spoilage.
IT IS NOT RECOMMENDED THAT PRESSURE PROCESSES IN EXCESS OF
15 PSIG BE APPLIED WHEN USING NEW PRESSURE CANNING
EQUIPMENT. MOST MANUFACTURERS ALSO DO NOT RECOMMEND
OPERATING THEIR PRESSURE CANNERS ABOVE 15 PSIG.
So-called canning powders are useless as preservatives
and do not replace the need for proper heat processing.
JARS WITH WIRE BAILS AND GLASS CAPS MAKE ATTRACTIVE
ANTIQUES OR STORAGE CONTAINERS FOR DRY FOOD INGREDIENTS BUT
ARE NOT RECOMMENDED FOR USE IN CANNING. ONE-PIECE ZINC
PORCELAIN-LINED CAPS ARE ALSO NO LONGER RECOMMENDED. BOTH
GLASS AND ZINC CAPS USE FLAT RUBBER RINGS FOR SEALING JARS,
BUT TOO OFTEN FAIL TO SEAL PROPERLY.