## 5 'Process-Based' Microbiological Criteria
### Aspects of Microbiological Criteria Related to Foods
It is therefore easy to conclude that we need a way to assess and determine the microbial quality of food in order to prevent illness caused by food unfit for human consumption, whether caused by introducing pathogens or by undesirable spoilage due to the influence of its natural microflora. These are Microbiological Criteria which provide the guidelines we need regarding what is acceptable and safe in food and its production. These criteria determine the acceptability of a product, production lot or process based on the absence, presence ornumber of pathogens or/and on the quantity of toxins (or metabolites) per unit of mass, volume, surface or per batch. Monitoring/controlling microorganisms in a food requires constant microbiological testing of samples from various stages of its production. The evaluation of this testing is made according to the predetermined Microbiological Criteria which set the acceptable range of values to which the microbiological parameters must comply. Different Microbiological Criteria are applied in each stage of production in order to ensure food is safe and will retain suitable quality to the end of its shelf life. Given the above, food microbiology is a scientific field which, today more than ever, is essential in the effort to guarantee the efficient monitoring of microbiological parameters in the <new type> of food products being produced today. Products which undergo minimal processing while simultaneously having maximum shelf life. Microbiological analysis is the most valuable scientific tool of food microbiology in this effort and its efficiency can be optimized when used in conjunction with quality control/hazard analysis systems (ISO/HACCP). The determination and development of Microbiological Criteria initially came about through consultation with the WHO/FAO [78] and continued to evolve through many revisions, following the contribution of the International Commission on Microbiological Specifications for Foods (ICMSF) [79]. Significant effort and funds are required for the development of effective Microbiological Criteria for a food or ingredient. Therefore Microbiological Criteria must be developed and put in place only when it is necessary and can prove effective and practical. In reality Microbiological Criteria have been set for specific bio hazards in specific food products by regulation 2073/2005 of the ICMSF [80]. Generally, Microbiological Criteria must be able to assess (1) the microbial quality of a food; (2) compliance to GHP (Good Hygienic Practices); (3) the suitability of a food or ingredient for a specific purpose and (4) the acceptance of an imported product originating from a country or region where production conditions are unknown or uncertain. Microbiological criteria for lot acceptance determinants fall into three categories based on regulatory consequences [81; 82]: (1) microbiological standard, a compulsory criterion incorporated into law or regulation; (2) a microbiological guideline, an advisory criterion to inform food operators of the microbial content that is expected in a food when best practices are applied; and (3) microbiological specifications, part of a purchasing agreement between a buyer and a supplier of a food. The state puts in place microbiological standards only when they are seen as necessary to guarantee the safety of food products subject to government regulatory control. Therefore, government bodies controlling food/food production manage the risk involved and through risk evaluation, may conclude that a microbiological criterion is necessary for a food, at different places in the food chain. Standards need to be based on tolerable level of risk and FSO for the biological hazard in question. Different types of microbiological testing (e.g., within lot, process control, investigational) may be used by industry and government). Lot microbiological testing represents one of the most common types, which compares a given microbial hazard detected in a food, to a pre-determined safety limit/range, i.e., a microbiological criterion.