標準號：BS ISO 14461-2-2005
中文標準名稱：乳和乳制品.微生物實驗室內質量控制.平行板和后續稀釋步驟的菌落計數可靠性測定
英文標準名稱：Milk and milk products - Quality control in microbiological laboratories - Determination of the reliability of colony counts of parallel plates and subsequent dilution steps
標準類型：X16
發布日期：2005/8/4 12:00:00
實施日期：2005/8/4 12:00:00
中國標準分類號：X16
國際標準分類號：07.100.30
適用范圍：This part of ISO 14461 | IDF 169 describes a routine procedure for the evaluation of results of the enumeration of microorganisms using colony-count methods with subsequent 10-fold dilution steps and one plate or two parallel plates within each dilution step. This routine procedure is applied regularly in each laboratory performing colony counts. It provides criteria for the acceptability of differences between the results from parallel plates and subsequent dilution steps, as follows. a) The results (colony counts) obtained from parallel plates are compared with tabulated limits for given colony counts. If these limits are exceeded, a technical problem when performing the parallel determinations may be indicated. b) The results (sums of colony counts) of two parallel plates of two subsequent 10-fold dilution steps are compared with tabulated limits for given sums of colony counts. If these limits are exceeded, a technical problem when performing the dilutions may be indicated. c) If the limits mentioned above are exceeded in more cases than expected, this indicates that the test procedure lacks reliability. NOTE The formulae for calculating the values in Table 1 and 2 are given and explained in Clause 7.