Putting Food By - Janet Greene [30]
In addition to the danger of inadequate processing, there is also the likelihood that a jar of food will burst in your face as you open the oven door.
Quite early in the marketing of microwave ovens to the general public, one maker touted his product as able to can fruits. In very short order the manufacturer discontinued such a claim for his oven. Now all responsible makers of microwave ovens warn against using them for canning. (Blanching produce as a preliminary treatment before freezing or drying may be done in a microwave.)
And No to Canning in an Automatic Dishwasher
(Scout’s honor, PFB keeps getting asked about this cockeyed theory.) It would be interesting to chart the thought processes behind such a procedure, since deluxe models reach an atmospheric heat of 140+ F/60+ C only when they’re set for extra hot cycles. In a home dishwasher, the temperature reached inside a container of food could only help produce a bacterial load that nobody needs.
And No to Canning in a Crockpot
We don’t know who could have advocated this, since we have never seen any such claims in print by the makers of Crockpots. But it has come up several times in letters to PFB, usually from writers who say they hope it’s safe, because they felt that slow-cooking was more likely to preserve nutrients than subjecting the food to heats like 240 F/116 C. All we need to say about a Crockpot is that if it’s on a long low-heat setting, chances are that the nastier micro-organisms will be encouraged to grow and breed like mad, and what else should you expect?
And No to Processing in a Compost Heap
Who ever would have thought it? But there was a query based on the notion of holding containers of food at 140 + F/60 + C for a long time.
And No to Canning Pills
“Canning pills” went out with corset-covers. Old manuals might suggest that salicylic acid (read this “aspirin”) be dropped in each canning jar before it was capped. Such things never helped then and would not help now. No preservative added can offset dirty handling or inadequate processing.
“Every-additive-at-once” preparations are used by some commercial canners, but none, thankfully, that PFB could discover is offered to home-canners by the salt industry.
THE STEAM CANNER
There came on the market in the late 1970s a canner devised to be a substitute for the not-always-deep-enough Boiling–Water Bath Canner, which manufacturers of housewares had been slow to produce in quantity at a reasonable price.
Initially, this newcomer was referred to as an “atmospheric steam canner,” so that it would NEVER be confused with the Pressure Canner. The canner was called “atmospheric” because the kettle is not sealed, and therefore the saturated steam inside it—not being under significantly more pressure per square inch than the air in the room outside—cannot get hotter than the boiling point of water in a utensil with an unsecured cover. Today, this piece of equipment is simply called a “steam canner.”
The models currently on sale in the U.S. resemble giant stove-top sterilizers for babies’ nursing bottles. They come in three sections: a shallow bottom to hold water that will boil hard to produce steam around the jars; a rack set just above the water to hold the jars of fruit or pickles; and a tall, domed lid that inverts to come down over the jars and rest on the lip around the edge of the water compartment. Small holes at the rim of the cover let steam escape near the base of the jars while they’re being processed.
In 1987, The Pennsylvania State University’s Center for Excellence researched the atmospheric canner’s performance using Boiling–Water Bath processing times. The canner’s results were disappointing. Needless to say, proponents of steam canners claim that the canners are perfectly safe, and some recent research backs up their claims. The USDA, however, has yet to endorse steam canning, and until the USDA changes its position, PFB will continue to withhold its approval.