Raw vegetables are used in raw packaging.
Raw packaging refers to the canning procedure of filling pots (or cans) with completely raw fruits or vegetables. This is in contrast to other canning methods, such as hot-packing, where fruits or vegetables can be boiled for a few minutes and immediately placed in cans and sealed. Each method can be used for a variety of different foods, but some foods are better suited for raw packaging than hot packaging and vice versa.
Raw packaging works well when canning pickled cucumbers or other vegetables.
The main thing to remember about raw food packaging is that the foods must be packed tightly together and in most cases are usually covered with canning water or canning liquid that is heated. Therefore, it is not the case that the raw packaging avoids placing extremely hot liquid in the canning jar. This heat, in addition to sterilizing the canning jars, minimizes the risk of food contamination. However, in general, this form of canning is great when you want to preserve semi-raw vegetables or fruits. It works particularly well with things that will be served crispy, like pickled cucumbers or other pickled vegetables.
If you’re canning fruit, raw packaging may not be as effective, especially if you plan on storing canned items for more than a few months. Most fruits, when exposed to air, begin to show some discoloration within a few hours of being sliced. When you package raw, you leave some of the air that the food already contains, and this can cause the raw packaged food to discolor in a few months. Hot packaging may be more appropriate because boiling food for a few minutes can help preserve the color and eliminate some of the air that fruits or vegetables naturally contain. A good canned food book can help you determine whether the food you want to preserve will work best with a raw or hot packaging method.
When you are canning at home, a main concern should be food safety. For this reason, the United States Department of Agriculture (USDA) provides guidelines on how to practice packaging raw materials safely. To keep your food fresh, pleasant and free from contamination, paying attention to these guidelines is very important. They are available online in PDF format and the most up-to-date cookbooks also note and explain food safety protocol, whether you pack raw, hot, or choose other methods of food preservation.