AOAC-RI ERP Book MICRO Sept 2016.pdf

February 20, 2013

and candidate method using both the traditional and alternative confirmation procedures, indicating no 1 significant difference between the candidate and reference methods at any of the time points. 4 obtained between the reference and candidate method samples confirmed using either the traditional or 5 alternative confirmation procedure at all four time points. The confidence intervals obtained for dPOD C 6 indicated no significant difference between the two methods. A dPOD CP value of 0.00 with 95% confidence 7 intervals of (-0.28, 0.28) was obtained between presumptive and confirmed results using either the 8 traditional or alternative confirmation procedure for all four time points. The confidence intervals obtained 9 for dPOD CP indicated no significant difference between the presumptive and confirmed results at all four 10 time points. 2 3 For the low level inoculum, a dPOD C value of 0.10 with 95% confidence intervals of (-0.19, 0.37) was For fresh spinach test portions, there were 11 confirmed positives the 3M Petrifilm SALX System for both 18 and 24 hour primary enrichment samples transferred to RV-R10 and incubated for 24 hours and confirmed following both the traditional and alternative confirmation procedures. For test portions enriched for 18 and 24 hours and transferred to RV-R10 and incubated for 8 hours there were 7 confirmed positives by the alternative confirmation and 11 confirmed positives by the traditional confirmation indicating the presence of 4 false negative results. There were 10 confirmed positives for samples analyzed by the FDA/BAM method. All un-inoculated control samples were negative by both methods. A χ 2 value of 0.10 was obtained between the reference method and the candidate method using the traditional confirmation for all four time points. For candidate samples confirmed following the alternative confirmation procedure, a χ 2 value of 0.10 was obtained for samples enriched for either 18 hours or 24 hours in the primary enrichment, transferred to RV-R10 and incubated for 24 hours. For candidate samples confirmed following the alternative confirmation procedure, a χ 2 value of 0.90 was obtained for samples enriched for either 18 hours or 24 hours in the primary enrichment, transferred to RV-R10 and incubated for 8 hours. The chi-square values indicate no significant difference between the candidate and reference method at any of the time points. Although there was no statistical significant difference between the number of positive test portions at 8 or 24 hours in RV-R10 (7 positive at 8 hours and 11 positive at 24 hours), it is recommended that only 24 hours of secondary enrichment in RV-R10 be used for fresh spinach. Secondary enrichment for 24 hours in RV-R10 significantly reduced the normal background microbial load, allowing the target organism to reach a higher titer and thus making it easier to identify presumptive Fresh Spinach obtained between the reference and candidate method samples confirmed using either the traditional or alternative confirmation procedures at all four time points. The confidence intervals obtained for dPODc intervals of (-0.28, 0.28) was obtained between the presumptive and confirmed results using the alternative confirmation for all four time points and for test portions incubated in the primary enrichment for either 18 or 24 hours and then incubated for a full 24 hours in RV-R10 and confirmed using the between the presumptive and confirmed results for test portions incubated in the primary enrichment for either 18 or 24 hours and then incubated for 8 hours in RV-R10. The confidence intervals obtained for all dPOD CP values indicated no significant difference between the presumptive and confirmed results at all indicate no significant difference between the two methods. A dPOD CP values of 0.00 with 95% confidence traditional method. A dPOD CP value of -0.20 with 95% confidence intervals of (-0.28, 0.28) were obtained positive colonies on the 3M Petrifilm SALX Plate. For the low level inoculum, a dPOD C value of 0. 05 with 95% confidence intervals of (-0.24, 0.33) was

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four time points.

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