53. In canning, as in all other tasks related to cookery, the housewife's aim should be to do the greatest amount of work, and do it well, with the least effort on her part. The results she gets in canning, then, will depend considerably on the orderly arrangement of the utensils and materials with which she is to do the work. But of greater importance is the preparation she makes to eliminate as much as she can the possibilities of contamination, for, as has been repeatedly pointed out, success in canning depends on the absence of dangerous bacteria.
54. From what has just been mentioned, it is essential that everything about the person who is to do the work and the place in which the work is to done should be clean. Clean dresses and aprons should be worn, and the hands and finger nails should be scrupulously clean. The kitchen floor should be scrubbed and the furniture dusted with a damp cloth. Any unnecessary utensils and kitchen equipment should be put out of the way and those required for canning assembled and made ready for the work. The jars should be washed and the covers tested by fitting them on without the rubbers. If a glass cover rocks, it does not fit correctly; and if a screw cover will not screw down tight, it should be discarded. Without the rubber, there should be just enough space between the cover and the jar to permit the thumb nail to be inserted as is shown in Fig. 3. The edge of each jar and each glass cover should be carefully examined every time it is used, so that none with pieces chipped off will be used, as these will admit air. This examination is made by running the finger over the edge of the jar and the cover, as is shown in Fig. 4. The jars, covers, and rubbers should be put into pans of cold water, and the water should be brought to the boiling point and allowed to boil for 15 minutes or more while the fruit or vegetables are being prepared for canning. They should be kept in the hot water until the food is ready to be placed in them. In the one-period cold-pack method, it is not necessary to boil the jars, rubbers, and covers, but this may be done if desired.
To produce good-looking jars of food, the fruit or vegetables to be canned should be graded to some extent; that is, the finest of the fruits or vegetables should be separated and used by themselves, as should also those of medium quality. Often it is wise to use the poorest foods for purposes other than canning. The food may then be canned according to the chosen method, but by no means should methods be mixed. In handling the product after it has been cooked by the open-kettle method, any spoon, funnel, or other utensil must be thoroughly sterilized in the same way as the jars and their covers and rubbers; indeed, no unsterile utensil should ever be allowed to touch the food when a jar is being filled.