AS 4659.3:2015 pdf download.Guide to determining the equivalence of food microbiology test methods Part 3: Confirmation tests.
4 PROCEDURE
4.1 Define the equivalence determination The equivalence determination should be defined in terms of the following: (a) The target organism’s genus, species, serotype, etc. (b) The alternate method—precisely defined by reference to a publication, manufacturer’s instructions and any optional procedures employed or deviation from the published method. (c) The reference method—including the specification of any optional steps. (d) The steps of the methods that are to be compared.
4.2 Define the conditions of the equivalence determination The conditions of the equivalence determination should be defined in terms of the following:
(a) The laboratory where testing is performed. (b) Controls observed by the laboratory during testing, for example, controls on the environment of the laboratory, prevention of cross contamination, controls on media and reagents, calibration of equipment, etc. where these factors are considered critical to the success of either method. (c) The staff performing the tests (experience, qualifications, etc.). (d) The starting and finishing dates of the tests. (e) The batch numbers of media, reagents, etc. used. NOTE: This information is deflned for the purpose of reporting on the equivalence determination and recording factors which may have some bearing on the results obtained. These factors do not necessarily affect the veracity of the study.
4.3 Select test organisms
Fifty strains should be selected. These are to include diversity in the strain selected. A minimum of 20 positive isolates and 20 closely related negative isolates should be selected. in addition, a minimum of’ 10 non-related strains should be tested. The reference cultures prescribed in the Australia Standard method should be included. The other strains may be selected from the following list (in order of preference): (a) Strains of’ the target organism isolated by the laboratory. (b) Strains of the target organism isolated by reference laboratories or industry sources as representative. (c) Strains of the target organism held by culture collections. The identity of the strains chosen should be determined by appropriate means (e.g. biochemical, physiological, serological, molecular) before performing further work. Consultation with a reference laboratory or an expert may be necessary. The source and identity of the strains should be recorded. NOTE: It is possible, by the selection of test strains, to bias the results of the study. Care should be taken to select representative strains which do not possess characteristics which are likely to lead to biased results being obtained.
4.4 Preparation of inoculum
The test strain inoculum should be such that at least equivalence in sensitivity to the reference method may be demonstrated. The strains chosen should be prepared as prescribed by the method being studied.
4.5 Testing
The reference method should be performed in parallel with the testing of the alternate method by the same operator or group of operators who are proficient in both methods under study. All results should be taken to the final stages of confirmation.
4.7 Acceptance criteria
The alternate method will only be accepted if B + C = 0. NOTE: If B or C is greater than zero then equivalence of the alternate method has not been adequately demonstrated. An explanation should be sought for the discrepancy. It may lie in the choice of test organism, the performance of a critical step in the alternate method or some other factor. Once the reason is determined, the procedure may be repeated, after redefining the test organisms where necessary, to fulfil the requirement that B = 0.
5 REPORT
The report should contain the following information: (a) All details necessary for identification of sample types. (b) Reference to this Standard (i.e. AS 4659.3) and other appropriate Australian Standards. (c) Reference to the alternative method. (d) Each step of the method above reported in full. (e) The results obtained. (f) Date of testing. (g) Any circumstances that may have influenced the result.AS 4659.3 pdf free download.