Preservation of foods is central to any food processing operation and specially important to small scale processors as it simplifies logistics. Food Technologists know that preserving acidic foods is safer and easier than low acidity foods and more appropriate to small scale processing.
Food Science a joint venture between CSIRO and the government of Victoria has published this as part of their online information for SME processors.
It defines the range of products and their acidity and defines processes that can be used. It focusses on the proven fact that so long as a foods equilibrium pH is below 4.5 there is no chance of food poisoning. It describes the various types of food spoilage organisms and compares their survival / activity under the conditions of processing.