AOAC-RI ERP Book MICRO Sept 2016.pdf

February 20, 2013

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For the low level inoculum, a dPOD C

value of 0.00 with 95% confidence intervals of (-0.27, 0.27) was

obtained between the reference and candidate method samples confirmed following both the traditional and alternative confirmation procedures at both the 18 hour and 24 hour primary

enrichment time points. The confidence intervals obtained for dPOD C

indicated no significant

value of 0.00 with 95% confidence intervals of (-0.27,

difference between the two methods. A dPOD CP

0.27) was obtained between presumptive and confirmed results using either the traditional and alternative confirmation procedures for both the 18 and 24 hour primary enrichment time points. The

confidence intervals obtained for dPOD CP

indicated no significant difference between the presumptive

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and confirmed results.

INDEPENDENT LABORATORY STUDY

The independent laboratory study was conducted at Aegis Food Testing Laboratories in North Sioux City, SD. The study was conducted according to the methods described above for raw ground chicken

and pasteurized liquid whole eggs.

Raw Ground Chicken

All uninoculated control samples of ground chicken were confirmed negative for Salmonella . The samples were inoculated S. enterica subsp. Enteritidis (NCTC 5717), with an estimated 0.031 cells/g as determined by MPN. The 3M Petrifilm SALXSystem detected 13 suspect colonies of which12 samples were presumptive when the confirmation disk was added. All 12 of the presumptive samples confirmed as positive by the USDA/FSIS MLG 4.05 reference method. There were 11 ground chicken samples that were determined to be positive by the reference method. When comparing the number of samples determined to be positive by the 3M Petrifilm SALX System to that of the reference method, there was no statistical difference in the results obtained (χ 2 <3.8, p<0.05). The number of samples that were presumptive positive from the 3M Petrifilm SALX System was compared to the number confirmed as positive using probability of detection (POD) and difference in probability (dPODcp). The 95% confidence interval for the dPOD for the 3M Petrifilm SALX System presumptive positives compared to the confirmed positive contains zero. Therefore, there was no significant difference in the results at the 5% level. The number of samples that were confirmed positive from the 3M Petrifilm SALX System was compared to the number confirmed as positive by the reference method using probability of detection (POD) and difference in probability (dPODc). The 95% confidence interval for the dPOD for the 3M Petrifilm SALX System confirmed positives compared to the reference method confirmed positive contains zero. Therefore, there was no significant difference in All uninoculated control samples of pasteurized liquid eggs were confirmed negative for Salmonella . The samples were inoculated with an estimated 0.008 cells/g of S. enterica subsp. Enteritidis (ATCC 13076, heat stressed) as determined by MPN. The 3M Salmonella Petrifilm System detected 7 suspect colonies of which 7 samples were presumptive when the confirmation disk was added. All 7 of the presumptive samples confirmed as positive by the USDA/FSIS MLG 4.05 reference method. There were 8 pasteurized liquid eggs samples that were determined to be positive by the reference method. When comparing the number of samples determined to be positive by the 3M Petrifilm SALX System to that of the reference method, there was no statistical difference in the results obtained (χ 2 <3.8, p<0.05). The number of samples that were presumptive positive from the 3M Petrifilm SALX System was compared to the number confirmed as positive using probability of detection (POD) and difference in probability (dPODcp). The 95% confidence interval for the dPOD for the 3M Petrifilm SALX System the results at the 5% level. Pasteurized Liquid Whole Eggs

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