Temperatures

• The main reason steam canners should not be used for foods low in acidity is because they do not process as sufficient temperatures to kill bacteria. Studies have shown that the manufacturers of steam canners offer instructions that would not result in proper bacteria retardation, and could result in spoilage of the product.
  
  

Fruits

• Foods that are high in acidity, such as fruits, are not susceptible to botulism, thus it would potentially be safe to use a steam canner to process them. However, processing at such low temperatures could still result in food spoilage.
  
  

Vegetables

• Vegetables are low in acidity. Never process vegetables in a steam canner. Processing vegetables in a steam canner could cause an overgrowth of botulism. Botulism is extremely toxic and in some cases it is fatal.
  
  

Meats

• Meats should never be processed in a steam canner. Meats are highly susceptible to all types of contaminants, and steam canners will never reach the temperatures required to safely kill all bacteria.