Measurement uncertainty in the enumeration of food micro-organisms

Numbers and types of microbes present in foods are important indicators of safety and quality. Microbiological testing of food can include testing for presence/ absence of pathogens, enumeration of microbial count of TBC, APC, TMC ,… or numbers of indicator organisms. Measurement uncertainty is defined as being a parameter associated with the result of a measurement that characterizes the dispersion of the values that could reasonably be attributed to the measurand (the particular quantity subject to measurement. Measurement uncertainty allows an assessment of the reliability of the result, for example in comparing the results from different sources of with reference values or criteria given in microbiological standards, guidelines or official control and formal samples. Evaluation of measurement uncertainty is a requirement for laboratories operating (ISO/IEC 17025, 2005) accreditation systems and this includes those carrying out microbiological examinations. According to ISO/IEC 17025, testing laboratories must report uncertainty estimates where specified by the method, where required by the client and/or where the interpretation of the result could be compromised by a lack of knowledge of the uncertainty. This should at least be the case where testing results have to be compared to other testing results or other numerical values, such as specifications. In any case laboratories should know the uncertainty associated with a measurement whether it is reported or not. International organizations as like as AOAC, NKML, ISO, NHS, CODEXS and IDF currently seeking to define and to provide measurements of uncertainty associated with methods used for enumeration of food micro-organisms.In this article , In this article different approaches estimating uncertainty of measurement in routine food microbiological quantitative tests like as A bottom-up (component by component) approach, alternative top-down (Type A) approach: GUM 108 method and estimation of Reproducibility values in determination of microbiological uncertainty were discussed