Title: Calibration according to ISO/IEC 17025 in the operation of microbiological and chemical laboratories: an exercise in creating control charts for TPC and TVB-N

A study and practice of laboratory equipment calibration together with TPC and TVBN methods of analysis according to ISO/IEC 17025 was conducted in order to gain and compile skills in calibration and internal quality checks of a laboratory using control charts in the two methods of analysis. The calibration facts and skills will be compiled into an equipment calibration manual while the two control charts will then give a rehearsal of internal quality checks of microbiological and chemical laboratories. All this is favourable to the Uganda Fisheries Laboratory as a step forward in gaining ISO7IEC 17025 accreditation to carry out analysis on fish and fish products for international export. In order to check performance of calibrated equipment and other quality parameters, which directly influence the microbiological results of analysis, a TPC control chart was obtained from the analysis of 10 frozen cod fillet samples for which the composite samples originated from the same consignment. The samples were prepared on the same day and then stored at -24ºC while inoculation was done along four consecutive days. Ten composite samples of shrimp muscle were prepared from 1000 g of a frozen consignment and then stored at - 24°C and TVB-N analysis carried out during five consecutive days to obtain a control chart. This was aimed at checking the consistence of the analytical results in order to carry out internal quality checks focused on various factors that may directly or indirectly affect the certainty of the results. One of the controls was ensuring that all the equipment was calibrated before use and the other was keeping the samples at - 24ºC to hold spoilage. From the control charts for TPC and TVB-N, the values from the sample fell within the acceptable region of the chart as expected.