HAPTER ONE
1.1   INTRODUCTION 
Canning food has been a labor of love for generations of families. Today has become an opportunity to take control of the food you and your family consume.
The key to successful canning understands the acidity and spoilage factor of the food you wish to can, as well as the acceptable canning methods to process those foods. There are two types of food, categorized as low acid (vegetable, meat, poultry and seafood) and high acid (fruits and tomatoes). Both can be successfully canned by pressure canning.
However, pressure canning is the only method recommended safe for canning low-acid foods according to the United State Department of Agriculture.
Canning is not the only condition in the manufacture and preservation of foods in which anaerobic conditions can developed.
In the 1900s, refrigeration practices unproved and sausages no longer caused a major problem with solution. However, as the technology for canning became availably, botulism became a problem in canned foods. By 1926, most of the problems in the commercial canning industry had been solved. Since then, most of the outbreak food borne botulism is the United State have caused by improperly home-canned foods, mostly fish and vegetables, such as string beans, corn, beets, spinach, asparagus and chili peppers.
Some canned cured meat products are given relatively mild heat processes, inhibitory action of the curing agents, and in some cases refrigeration, being depended on to prevent spoilage by organisms in groups 2 and 3. It is usual for spores of aerobic bacilli to survive in some of these products.
Glass home canning jars, sometimes referred to as Mason Jars, are made of heat-tempered glass for durability and reuse. These are the only jars recommended for safe home canning. They are available in standard sizes and will withstand the heat of a pressure canner, time after time.
The two-piece home canning vacuum cap (lid and band) is the recommended closure for home canning. It consists of a flat metal lid with a rubber like seal on the underside and a threaded metal screw band that secures the lid during processing. The bands can be used repeatedly if they remain in good condition; however, new lids must be used each time.
There are four basic agents of food spoilage-enzymes, mold, yeast, and bacteria. Canning will interrupt the natural spoilage cycle so food can be preserved safely. Pressure canners should be thoroughly examined and tested at the country extension office or with the manufactures to ensure their proper operation.
Canned tomatoes are the most widely home-canned product in the United States. They also are one of the most commonly spoiled home-canned products. The canning processes recommended in this fact sheet are the result USDA research on safe home-canning procedures for tomatoes and tomatoes product. 
Spoilage Canned Food: The most common reasons for spoilage in home-canned tomato products are under processing and incomplete seeks.
Tomatoes that have not been processed long enough to destroy molds and heat-resistant bacteria may spoil during storage. One of the common spoilage organisms in canned food, bacillus coagulans, is very heat resistant and causes flat-sour spoilage. The jars lid may still be sealed and the product may appear normal, but the tomatoes will smell sour because of lactic acid produced by the growth of B. coagulans in the product.